The mass of melted gold to release the energy would be 3, 688. 8 Kg
How to determine the massWe have quantity of energy is;
Q = n × HF
n = number of moles
HF = heat of fusion
Let's find number of moles
235.0 = n × 12.550
number of moles = [tex]\frac{235}{12. 550}[/tex] = 18. 725 moles
Note that molar mass of Gold is 197g/ mol
Number of moles = mass/ molar mass
Mass = number of moles × molar mass
Mass = 18. 725 × 197
Mass = 3, 688. 8 Kg
Thus, the mass of melted gold to release the energy would be 3, 688. 8 Kg
Learn more about molar heat of fusion here:
https://brainly.com/question/15634085
#SPJ1
Temperature and wind combine to cause heat loss. Hypothermia occurs when the body temperature falls more than 4 °F below normal. Death can occur if hypothermia persists for over 3 hours. According to the chart, in which of the following temperature and wind combinations would the body temperature be the lowest and a person most at risk for developing hypothermia?
According to the chart, the combination that would result in the lowest body temperature and highest risk of developing hypothermia would be option E: wind speed of 25 mph and a temperature of 35 °F. At this combination, the "feels like" temperature is -22 °F, which is well below the threshold for hypothermia. It is important to note that this chart only calculates the "feels like" temperature and other factors such as clothing, humidity, and overall health can also affect a person's risk of developing hypothermia
What is the pH of 0.20 M nitrous acid at equilibrium (Ka= 4.6×10-4)?
The pH of the solution of the nitrous acid is 2.04.
What is the pH of the nitrous acid?We know that we can be able to obtain the pH of the acid when we look at the dissociation of the acid and then we would be able to have that in the dissociation there would be at equilibrium;
[tex]HNO_{2}[/tex](aq) + [tex]H_{2} O[/tex](l) ⇔ [tex]H_{3} O^+[/tex](aq) + [tex]NO_{2}^-[/tex](aq)
I 0.20 0 0
C -x +x +x
E 0.2 - x x x
Then we have;
4.6×10^-4 = x^2/0.2 - x
4.6×10^-4(0.2 - x) = x^2
9.2 * 10^-5 - 4.6×10^-4x = x^2
x^2 + 4.6×10^-4x - 9.2 * 10^-5 = 0
x=0.009 M
pH = - log(0.009)
pH = 2.04
Learn more about pH:https://brainly.com/question/15289714
#SPJ1
Select the classification for the following reaction. KOH(aq) + HCl(aq) → KCl(aq) + H2O(1) O None of these choices is correct. O acid-base O precipitation O combination O redox
Acid-base is the classification for the following reaction. KOH(aq) + HCl(aq) → KCl(aq) + H2O(1) .
What are acids and bases?Because bases absorb hydrogen ions while acids produce them, acids and bases differ chemically from one another. Anything that counteracts acids is a basic. When bases are added to water, they break, releasing hydroxide ions, or OH-. When a base is added to water, the result is referred to as an alkaline solution. Any hydrogen-containing material that has the ability to donate a proton (hydrogen ion) to another chemical is considered an acid. A base is a molecule or ion that can take up an acid's hydrogen ion. Typically, sour tastes help to identify acidic chemicals.
When an acid and a base mix, the matching salt and water are created. An acid-base reaction is what is happening here. The neutralization reaction is another name for the acid-base reaction.
Learn more about Acid-base refer to :
brainly.com/question/9836972
#SPJ4
A reaction requires 2.5 moles of zinc oxide. How many grams would this equate to?
A. 81.4 g
B. 163.5 g
C. 203.5 g
D. 32.6 g
Which of the following does NOT occur in an ionic bond?
Two atoms share an electron.
A bond is formed between a positive and negative ion.
An electron is transferred from one atom to another.
Forms between a metal and a nonmetal element.
Answer: its the first answer
Explanation:
what is the hybridization of nitrogen in each of the following ions and molecules?
NO+2 has Linear molecule have sp hybridization, N205 has Angular molecule has sp² hybridization, NO2- has Linear molecule have sp hybridization, N2O3 has Trigonal planar molecule has sp² hybridization, N20 has Trigonal planar molecule has sp² hybridization. Linear molecule have sp hybridization.
Hybridization is a concept in chemistry that describes the way in which atomic orbitals combine to form new hybrid orbitals in molecules. Hybridization occurs when an atom's valence electron orbitals (s, p, and d orbitals) mix or "hybridize" to form new orbitals with different energy levels and electron distribution. The most prevalent hybridization types are sp3, sp2, and sp hybridization. Four atomic orbitals (one s-orbital and three p-orbitals) combine to form four sp3 hybrid orbitals in sp3 hybridization.
Learn more about Hybridization here:
https://brainly.com/question/29020053
#SPJ4
The complete question is :
what is the hybridization of nitrogen in each of the following ions and molecules?
NO+2, N2O5,NO2-,N2O3,N20
Sequence the events of the Big
Bang Theory in correct order:
Hydrogen and helium form.
Heavy elements form.
Planets form.
Stars and galaxies form.
Subatomic particles form.
The prevailing theory describes a peculiar form of energy that can suddenly push to form the nuclei of simple elements: hydrogen, helium and lithium.
what is elements?An interesting opportunity to look at the relationship that currently exists between chemists and philosophers of chemistry is the question of the conceptual nature of the term "element."The English scientist Robert Boyle was the one who first proposed the chemical element. He stated that an element is a substance that is "incapable of decomposition" and added the prophetic by any means that we are now familiar with, just like a true scientist. Boyle's definition is remarkably accurate in terms of current theory. A chemical element is a species of atoms, including the pure substance made entirely of that species, that have a specific number of protons in their nuclei. Chemical elements, in contrast to chemical compounds, cannot be reduced by any chemical reaction into simpler substances. The laboratories have changed certain components.To learn more about chemical reaction refer to:
https://brainly.com/question/11231920
#SPJ1
Enter the nuclear equation for the alpha decay of polonium-216 (21684Po).
Express your answer as a nuclear reaction.
Through the reaction Po Pb + ta, the Po-216 undergoes alpha decay and transforms into lead (Ph-212).
What's Po's nuclear equation?The Polish scientist Marie Curie and her husband Pierre discovered polonium in 1898, the first naturally occurring unstable element that was isolated. Po21284, Pb20882, and He42 are released when it decomposes. An oxygen isotope called 17O was the first nuclide to be created artificially.
Physical half-life for polonium-210 is 138 days. As lead-206 is produced by radioactive decay, alpha particles are released. Although the alpha particles have a relatively small range, they are quite energetic.
learn more about polonium-210
https://brainly.com/question/16979893
#SPJ4
What is the Insight's rating in kilometers per liter?
Answer:
I don't use this
Explanation:
consider the titration of 50ml of 0.1M CH3COOH with 0.1M. Calculate before addition of any KOH (Ka=1.8×10-⁵)
Answer:
c i took the test
Explanation:
Without decomposers, ecosystems would likely:
be home to more producers.
overflow with waste products like dung and dead leaves.
become more biodiverse.
expand and become healthier.
Without decomposers, ecosystems would likely B.overflow with waste products like dung and dead leaves.
What will happen to the ecosystem in the absence of the decomposers ?The flow of materials and energy would stop if decomposers were eliminated from a food chain. Dead organisms and waste would accumulate. Because nutrients would not be released back into the ecosystem from the waste and dead creatures, producers would not have enough nutrients.
Dead leaves, dead insects, and dead animals would accumulate everywhere if decomposers weren't present. Just picture how the world might appear! More significantly, decomposers enable the primary producers of an ecosystem, typically plants and algae, to access essential nutrients.
Therefore, option B is correct.
Learn more about ecosystems at:
https://brainly.com/question/842527
#SPJ1
When the following ester is treated with lithium iodide in DMF, a carboxylate ion is obtained: you to foron This reaction follows which mechanism? O The substrate is secondary and iodide is a strong nucleophile, so this will be an Sn2 mechanism. O The substrate is primary and iodide is a weak nucleophile, so this will be an Sn1 mechanism. O The substrate is secondary and iodide is a weak nucleophile, so this will be an Spi mechanism. O The substrate is primary and iodide is a strong nucleophile, so this will be an Sp2 mechanism.
Lithium iodide treatment of an ester in DMF results in the formation of a carboxylate ion.
How do carboxylate ions develop?By deprotonating carboxylic acids, carboxylate ions can be produced. When an acid has a pKa of less than 5, it can be deprotonated by a variety of bases, including sodium hydroxide and sodium bicarbonate. RCOO R C O O is the generic form of a carboxylate group. A carboxylate group's carbon forms a double bond with one oxygen and a single bond with a different oxygen. The answer is that NO, carboxylate and carboxyl groups are not the same. Organic substances with a -C(=O)O- anionic group are known as carboxylic acid salts or carboxylate salts. The common formula for carboxylate salts is M(RCOO)n, where M is a metal or cation such as ammonium. The negative charge delocalizes in the vicinity of the oxygen atoms.To learn more about carboxylate ion, refer to:
https://brainly.com/question/15461099
#SPJ4
Write an equation for the reaction that occurs when aspirin is hydrolyzed in the body?
A heterodimer of PAFAH1b2 and PAFHA1b3 hydrolyzes aspirin in plasma as well as within erythrocytes in the blood (19) and in plasma. The cyclooxygenase enzymes' active site contains serine residues that aspirin binds to and acetylates.
The definition of "hydrolyzed food"The protein molecules in the diet have been chemically changed through a procedure called hydrolysis so that they can be disassembled into their simplest forms in hydrolyzed protein dog food (amino acids and peptides).
Why are proteins hydrolyzed?She explains that the hydrolyzed process converts protein into shorter-chained amino acids, promoting faster absorption and enabling faster muscle repair and rebuilding. Because hydrolyzed protein absorbs nutrients more quickly, it may help your muscles absorb BCAAs more quickly.
To know more about Hydrolyzed visit:
https://brainly.com/question/29522913
#SPJ4
You purchase a rare species of plant that acquires oxygen through the solution it is placed in. Knowing that the plant will be kept outside over the scorching summer, what type of solution should the plant be placed in to assure that it receives the greatest amount of oxygen possible?
Plants produce their nourishment through a process called photosynthesis. They generate energy in the shape of glucose using water, carbon dioxide, and sunshine.
What does a high glucose level mean?Because the body doesn't produce enough insulin, hyperglycemia (increased blood glucose) occurs when there is excessive sugar in the blood. Hyperglycemia, a sign of diabetes, can lead to vomiting, intense hunger and thirst, a rapid heartbeat, eyesight issues, and other complaints.
Does glucose lead to weight gain?High blood glucose concentrations can be caused by eating more carbs than what the body can utilize. The reason for this is that the body converts carbohydrate into simple sugars. Ineffective cell removal of carbohydrates from the blood results in the body storing it as fat in the tissues. Weight gain may result from this.
To know more about glucose visit:
https://brainly.com/question/2396657
#SPJ1
One Angstrom, Symbolized A, Is 10-10 M. 1 Cm3=________,A3 A) 1024 B)10-24 C 1030 D) 10-30
E) 10-9
10-24 A3.
What is angstrom in measurement ?The angstrom (Å) is a unit of measurement for length, equal to 10^-10 meters (0.1 nanometers). It is often used in physics and chemistry to express the sizes of atoms, molecules, and lengths of chemical bonds. The unit is named after the 19th-century Swedish physicist Anders Jonas Angstrom.
1 cm^3 is equivalent to 1x10^24 A^3. This is because 1cm^3 = 1 x 10^-6 m^3 and 1 Angstrom = 10^-10m. So, 1cm^3 = 1 x 10^-6 x (10^-10)^3 = 1 x 10^-6 x 10^-30 = 1 x 10^-36 A^3, which is equal to 1 x 10^24 A^3.
To know more about chemical bonds ,visit:
https://brainly.ph/question/1710513
#SPJ4
Complete the following statement for electrolysis of an aqueous salt solution:
When two half-reactions are possible at an electrode, the reduction with the (less/more) negative, meaning the (more/less) positive, electrode potential occurs.
When two half-reactions are possible at an electrode, the reduction with the less negative electrode potential occurs, and the oxidation with the less positive electrode potential occurs is Electrolysis of Aqueous Salt solutions.
What is electrolysis?Water is split into hydrogen and oxygen by a process called electrolysis. In a device known as an electrolyzer, this reaction occurs. Electrolysis is a method used in chemistry and industrial to force a chemical reaction that would not otherwise occur naturally. Commercially speaking, electrolysis is a crucial step in the electrolytic cell-based separation of elements from naturally existing sources like ores. Compared to laser hair removal, electrolysis is thought to be more painful. Compared to laser hair removal, it could take more sessions, but each one is less expensive. Although laser hair removal is a quicker and less unpleasant procedure, it costs more per appointment.When two half-reactions are feasible at an electrode, electrolysis of aqueous salt solutions results in the reduction with the less negative electrode potential and the oxidation with the less positive electrode potential.
To learn more about electrolysis refer to:
https://brainly.com/question/12994141
#SPJ4
What is the Lewis dot structure for an element that will form an ion with a charge of 3+?
For Ionic compounds, the Lewis Dot Structure must show how the electrons are being transferred to form the ions in the compound.
What is the Lewis dot structure for ions?In covalent compounds, the Lewis Dot Structures must appear how the electrons are being split to complete the octets of each atom in the molecule. hen compute the number of total valence electrons of the ionic compounds.
Lewis electron dot picture uses dots to represent valence electrons throughout an atomic symbol. Lewis electron dot diagrams for ions have fewer (for cations) or more (for anions) dots than the communicate atom. To draw the Lewis dot structures we must know the valence electrons on each atom attending in the given ionic compounds.
So we can conclude that n a covalent mixture, the Lewis Dot Structures must show how the electrons are being.
Learn more about Lewis here: https://brainly.com/question/20300458
#SPJ1
How many atoms of hydrogen are present in Ammonium Nitride (NH4)3N?
The answer is 4 hydrogen 3 oxygen
Answer: 2.408*10^24 in a mole or 4 in one molecule.
Explanation:
Consider the decomposition of gaseous N2O4:
N2O4(g)?2NO2(g) ?H? = +55.3 kJ, ?S? = +175.7 J/K. Estimate the temperature at which the reaction becomes spontaneous.
Show work i just need to know how to calculate this, my method isnt working.
In order for gaseous N2O4 to decompose, the temperature must be lower than 314.74 K. Gas is a condition of circumstances that is neither set in size nor shape.
Compared to other material states, such as solids and liquids, gases have lower densities. There is a lot of kinetic energy in the empty space between particles. Gaseous substance has no volume and no shape, but it will expand to fill a container completely. Anything having to do with a gas or having traits of gases should be described using the term gaseous. Gaseous particles are often odourless, although you can occasionally see them. "in a gaseous condition," 1799; from gas (n.) + -ous. Gaseousness is associated. Things like oxygen, carbon dioxide, nitrogen, hydrogen, helium, steam, and dry ice are typical examples of gases.
learn more about gaseous here:
https://brainly.com/question/4594811
#SPJ4
at which of the following ph values does the amino acid have the best buffering capacity?
A. 3.00
B. 1.53
C. 10.5
D. 6.01
E. 9.00
F. 2.34
The amino acid has the best capacity for a buffer at a pH of 9.69. To assess whether an aqueous solution is basic or acidic, chemists use the pH scale.
"Potential of hydrogen" is what pH stands for. The negative log base 10 of the hydronium concentration is what is referred to as pH. The pH serves as a logarithmic gauge of the concentration of hydrogen ions in a solution. On the scale, neutrality is represented by 7, and ranges from 0 to 14. While pH values above 7 denote baseness, pH values below 7 imply acidity. The pH scale really measures the concentration of free hydrogen and hydroxyl ions in water. As a result, weak bases and acids have their highest buffering capabilities at large K values.
To learn more about pH click here https://brainly.com/question/491373
#SPJ4
How many significant figures are in 2.00 x 10^28?
Answer:
i think 2 figure ..............
Answer: 3
Explanation:
use the figure to predict the results of lederberg and tatum’s experiment. (figure 1)
A. figure 1
B. figure 2
C. figure 3
According to the lederberg and tatum's experiment, the bacteria cultures will grow on minimal in flask 3.
Minimal media only supports growth of wild-type bacteria for all growth requirements. This experiment took advantage of the ease of growing and maintaining bacteria. Bacteria grow in isolated colonies on the plate. With the addition of proline, minimal media can support the growth of probacteria, but these bacteria must be wild-type for other genes. Lines 1 and 2 have additional mutations and are auxotrophs, so they do not grow under these conditions. However, when combined together in Flask 3, gene exchange may occur between these two auxotrophs, resulting in a prototroph that is wild-type for all growth requirements and capable of growth under these conditions. can be generated.
Learn more about bacteria here:
https://brainly.com/question/1537981
#SPJ4
The complete question is Use the figure to predict the results of lederberg and tatum’s experiment. (figure 1)Bacterial cultures from which flask(s) will grow on minimal medium? Select all that apply.
A. flask 1
B. flask 2
C. flask 3
the ph of a 0.10 m solution of a weak base is 9.82. what is the kb for this base
the ph of a 0.10 m solution of a weak base is 9.82.the kb for this base is 4.35*10^-8
To do this, we multiply 14-9.82=pOH by 4.18 to get the pOH. Now we must locate [OH-]. We take the equation 4.18=-log[OH-] and multiply it by the inverse to get 10-4.18 and 6.60*10-5 [OH-]. The equalibrium expression for a weak base must now be written. (BO-X), [BO] -> [B][O], so Kb = [OH-]2 / ([Base]-[OH-]), But we know the concentration of the solution and the OH-, so when we add these values together, we get...Kb= (6.60*10^-5)^2 / (.10 - 6.60*10^-5), Kb=4.35*10^-8
The pH of a solution illustrates its acidity or basicity.The pH of a neutral solution is 7.0, and A solution with a pH less than 7 is considered acidic, while one with a pH greater than 7 is regarded basic. The equation for the pH of a solution of a weak base is: pH = pKb + log([B-]/[B]) where [B-] is the concentration of the conjugate acid of the base, [B] is the concentration of the base, and pKb is the base dissociation constant.
Learn more about pH here:
https://brainly.com/question/2288405
#SPJ4
Describe an experiment that can be used to prepare a solid sample of sodium hydrogen (3 marks) carbonate in the laboratory starting with sodium metal.
An experiment that can be used to prepare a solid sample of sodium hydrogen carbonate in the laboratory starting with sodium metal involves the following steps below:
We have to dissolve about 5 grams of anhydrous sodium carbonate in about 25 ml of distilled water in a flask.The solution has to be cooled by subjecting to a low temperature which involves keeping the flask in a freezing mixture. Carbon dioxide gas should be added to the solution.Crystals of sodium bicarbonate will precipitate out after sometime which is filtered and dried for optimal yield.What is an Experiment?This is referred to as a scientific test in which series of actions are done and their effects carefully observed in order to learn about something or make new findings.
Anhydrous sodium carbonate is dissolved in water and cooled after which carbon dioxide is passed into the solution to give crystals of sodium bicarbonate thereby making it the correct choice.
The equation for the reaction is:
Na₂CO₃ + CO₂ + H₂O →2NaHCO₃
Read more about Sodium hydrogen carbonate here https://brainly.com/question/14240995
#SPJ1
3. Calculate the volume (mL) of aqueous 40% sucrose having a density of 0.911 g/mL, required to furnish 1.5 mol C atoms (sucrose C12H22011; C = 12, H = 1,0 = 16).
As a result, 1.153 mol/kg of aqueous 40% sucrose, which has a density of 0.911 g/mL, is needed to produce 1.5 mol of carbon atoms.
What is density?The mass of a material substance per unit volume is known as density. Density is described by the equation d = M/V, where d stands for density, M for mass, and V for volume. Density is often measured in grammes per cubic centimetre. The sign is most usually used to represent density, however the Latin letter D can also be used. Mass divided by volume is the formula for density in mathematics: displaystyle rho = frac mV, where is the density, m is the mass, and V is the volume.
How is density measured?The density of an object is determined by its mass to volume ratio. Density is usually measured in grammes per cubic centimetre (g/cm3). A volume is measured in cubic centimetres, not grammes, so keep that in mind (the same volume as 1 milliliter). Glycerol (also known as glycerin) is denser than water (1.26 g/cc). Glass is sometimes described as a particularly viscous, slow-moving liquid (although it has lots of properties of a solid, like rigidity). It is denser than water. Even saltwater is less dense than water.
Molality = molarity ÷ density
Molarity of sucrose = 1.05 M = 1.05 mol/L
Density of sucrose = 0.911g/mL = 0.911 g/mL × 1 kg/1000 g × 1 mL/ 0.001 L = 0.911kg/L Molality = 1.05mol/L ÷ 0.911kg/L = 1.153 mol/kg
To know more about Density visit:
https://brainly.com/question/11780417
#SPJ1
how many atoms are indicated by the prefixes for each of the following items. drag each item to the appropriate bin
One atom of monosulfide, two of dinitrogen dioxide, three of tribromide triphosphorus, four of tetraiodide tetrachloride, five of pentaoxide, and six of hexachloride make up the compound.
How do atoms function?The atom is the primary building block of matter in the universe. Atoms are made up of a very small number of considerably smaller particles. The components of an atom are protons, neutrons, and electrons. Atoms that fit with other atoms form the building blocks of matter.
How are atoms created?Atomic structure. A tiny nucleus and electrons in orbit make up an atom. The positive charge of protons, which are located in the nucleus, is equal to the negative charge of electrons. The nucleus may also include neutrons.
To know more about atoms visit:
https://brainly.com/question/13654549
#SPJ4
Consider the fire fighting measures shown. Why does sodium require a Class D fire extinguisher instead of one that might spray water?
A. It may create table salt, sodium chloride.
B. The sodium will react with the water, creating an acid.
C. A regular fire extinguisher might break the sodium down.
D. The sodium will react with the water, causing a flash fire.
Water reacts with the combustible substances forming more fire and flashes. That is why sodium require a class D fire extinguisher instead of spray water.
What is class D fire extinguisher ?Combustible metal fires, such as those involving aluminum, titanium, magnesium, sodium, and potassium, are classified as class D fires. These kinds of fires frequently happen in industrial, manufacturing, or laboratory environments.
When metal fines, thin metal particles, frequently produce dust during the machining process ignite and become the fuel element in the fire triangle. Class D flames are difficult to extinguish and can result in substantial damage.
A Class D fire extinguisher must always be used to put out a flammable metal fire. Smothering the fires and removing the oxygen source is the most effective approach to put out these fires. The agent also aids in absorbing the fuel's heat. Hence, option D is correct.
Find more on fire extinguisher;
https://brainly.com/question/28901632
#SPJ1
12.24 cm (wavelength of a microwave oven) express your answer using three significant figures.
Changing over to milliliters and adjusting to two noteworthy figures gives a volume of 7.8 mL.
What is the vitality of microwave of wavelength 12.2 cm?Considering the recurrence of 2,450 MHz, the wavelength of microwave broiler radiation is almost 12 cm and the quantum vitality of a microwave photon is almost 1 x 10-5 eV.
How numerous moles of solute are there in 250.0 milliliters of a 4.0 moles per liter solution?Using dimensional examination, we are able figure out how numerous moles of solute are in 250 mL of arrangement. 250mL x (1L/1000mL) x (0.4mol/1L) = 0.1 mol.
To learn more about microwave broiler radiation here:
https://brainly.com/question/13934832
#SPJ4
A plot of ΔG (kJ/mol) vs. T (K) yields a straight line with the equation: y = -152.343x + 376.490. What is the value of ΔS (kJ/mol) for the reaction, based on this data? Express your response to two digits after the decimal.
we cannot find the value of ΔS (kJ/mol) which determines change in entropy in standard state. for the reaction as we need to have the ΔH to find ΔS.
To calculate ΔS from the equation of the line y = -152.343x + 376.490, we need to know the value of ΔH for the reaction. Without this information, we cannot calculate ΔS. The equation of the line y = -152.343x + 376.490 represents the variation of ΔG with temperature. ΔG represents change in free energy . The slope of the line is -152.343 kJ/mol K, which is equal to -ΔG/T. The y-intercept of the line is 376.490 kJ/mol, which is equal to ΔG at T = 0.So, the plot of ΔG (kJ/mol) vs. T (K) gives us the information about ΔG and its variation with temperature. But we need to know ΔH to find ΔS.
Learn more about change in free energy here:
https://brainly.com/question/15081056
#SPJ4
Explain why Na could bond with F and Be could bond with Br?
Show all formulas and names of all possible molecules formed with the elements in the question above?
Na (sodium) and F (fluorine) can bond because they have different electronegativities. Electronegativity is a measure of an atom's ability to attract electrons to itself. Fluorine is one of the most electronegative elements on the periodic table, while sodium is one of the least electronegative. This creates an electrostatic attraction between the two atoms, allowing them to form a chemical bond. The bond between Na and F is called an ionic bond.
The ionic bond between Na and F is formed when the sodium atom loses one electron to form a Na+ cation, and the fluorine atom gains one electron to form a F- anion. The resulting molecule is NaF.
Be (beryllium) and Br (bromine) can bond because they also have different electronegativities. Be is less electronegative than Br, and this creates an electrostatic attraction between the two atoms, allowing them to form a chemical bond. The bond between Be and Br is called a covalent bond.
The covalent bond between Be and Br is formed when both atoms share electrons. The resulting molecule is BeBr2 (Beryllium dibromide).
In general, it's important to note that the type of bond formed between two atoms depends on their electronegativities, if they are similar they tend to form covalent bond and if they are different they tend to form ionic bonds.