Suppose a piece of silver jewelry contains 7.49x10^22 atoms of silver (Ag). how many moles of silver are in the jewelry?​

Answer:

2.7 °C.kg/mol

Explanation:

Step 1: Calculate the freezing point depression (ΔT)

The normal freezing point of a certain liquid X is-7.30°C and the solution freezes at -9.9°C instead. The freezing point depression is:

ΔT = -7.30 °C - (-9.9 °C) = 2.6 °C

Step 2: Calculate the molality of the solution (b)

We will use the following expression.

b = mass of solute / molar mass of solute × kilograms of solvent

b = 102. g / (162.2 g/mol) × 0.650 kg = 0.967 mol/kg

Step 3: Calculate the molal freezing point depression constant Kf of X

Freezing point depression is a colligative property. It can be calculated using the following expression.

ΔT = Kf × b

Kf = ΔT / b

Kf = 2.6 °C / (0.967 mol/kg) = 2.7 °C.kg/mol

Answer:

Hello There!!

Explanation:

The atom is still 24Na.

hope this helps,have a great day!!

~Pinky~

Answer: what are the choices?!.

Explanation:

Answer:

AlCl3 + 3NaOH ———>Al(OH)3 + 3NaCl

Answer:

His results will be skewed because there was more water than stock solution. Which would cause the percentage solution to be less than 50% therefore the density would be less than the actual value.

Explanation:

The solution will have percentage less than that of 50%. Therefore the density would be less than the actual value.

Suppose there should be 50 mL of the solution, and he added 60 mL. So 10 mL of the solution is added more.

Suppose the mass of the solute is m.

Originally, the density is = [tex]$\frac{m}{50}$[/tex]     [tex]\left(\frac{\text{mass}}{\text{volume}}\right)[/tex]

Now after adding extra 10 mL , the density becomes [tex]$\frac{m}{60}$[/tex].

Therefore, [tex]$\frac{m}{50}>\frac{m}{60}$[/tex]

So the density decreases when we add more solution.

Answer:

75.12 J

Explanation:

Applying,

Q = CΔT................ equation 1

Where Q = amount of heat, C = Heat capacity, ΔT = temperature rise.

From the question,

Given: C = 62.6 J/K, ΔT = 1.20°C

Substitute these values into equation 1

Q = 62.6(1.20)

Q = 75.12 J

Hence the amount of heat it absorbed is 75.12 J

Explanation:

Efficiency = (output/input)×100%

70% = output/(800 W)

which means

output = 0.70×(800 W) = 560 W

Answer:

0.287 M

Ba(OH)₂ + 2 HClO₄ ⇒ Ba(ClO₄)₂ + 2 H₂O

1.62 M

Explanation:

Step 1: Calculate the concentration of Ba(OH)₂

We will use the following expression.

[Ba(OH)₂] = mass Ba(OH)₂/ molar mass Ba(OH)₂ × liters of solution

[Ba(OH)₂] = 2.29 g/ 171.34 g/mol × 0.0466 L = 0.287 M

Step 2: Write the balanced neutralization equation

Ba(OH)₂ + 2 HClO₄ ⇒ Ba(ClO₄)₂ + 2 H₂O

Step 3: Calculate the reacting moles of Ba(OH)₂

25.5 mL of 0.287 M Ba(OH)₂ react.

0.0255 L × 0.287 mol/L = 7.32 × 10⁻³ mol

Step 4: Calculate the reacting moles of HClO₄

7.32 × 10⁻³ mol Ba(OH)₂ 2 mol HClO₄/1 mol Ba(OH)₂ = 0.0146 mol HClO₄

Step 5: Calculate the concentration of HClO₄

0.0146 moles of HClO₄ are in 8.99 mL of solution.

[HClO₄] = 0.0146 mol/0.00899 L = 1.62 M

Answer:

See explanation and images attached

Explanation:

The first image shows the structure of hydrogen peroxide. It does not exist as resonance structures. The structure and properties of the molecule can wholly be explained on the basis of a single Lewis structure.

However, the structure of the bicarbonate ion in sodium bicarbonate can not be completely described by a single Lewis structure. Hence, two resonance structures are shown for the bicarbonate ion. In each case, Na^+ is the counter ion.

Answer: The millimoles of potassium iodide the chemist has added to the flask is 522 millimoles.

Explanation:

Given: Volume of KI = 370.0 mL (1 mL = 0.001 L) = 0.37 L

Molarity of KI solution = 1.41 mol/L

Now, moles of KI (potassium iodide) is calculated as follows.

[tex]Moles = Volume \times Molarity \\= 0.37 L \times 1.41 M\\= 0.5217 mol[/tex]

Convert moles into millimoles as follows.

1 mol = 1000 millimoles

0.5217 mol = [tex]0.5217 mol \times \frac{1000 millimoles}{1 mol} = 521.7 millimoles[/tex]

This can be rounded off to the value 522 millimoles.

Thus, we can conclude that the millimoles of potassium iodide the chemist has added to the flask is 522 millimoles.

Answer:

Semi Metals-Boron, Silicon

Noble Gasses-Helium, Argon

Halogens-Clorine, Iodine

Transition metals-Iron, Tungsten

Alkaline earth metals-Calcium, Magnesium

Answer:

For (a): The moles of Ar is 16.94 moles

For (b): The moles of [tex]Cl_2[/tex] is 16.94 moles

For (c): The total number of moles in a tank is 23.47 moles

For (d): The mole fraction of Ar is 0.722

For (e): The mole fraction of [tex]Cl_2[/tex] is 0.278

For (f): The partial pressure of Ar is 2.888 atm

For (g): The partial pressure of [tex]Cl_2[/tex] is 1.112 atm

Explanation:

The number of moles is defined as the ratio of the mass of a substance to its molar mass.  The equation used is:

[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}[/tex] ......(1)

Given mass of Ar = 675.5 g

Molar mass of Ar = 39.95 g/mol

Plugging values in equation 1:

[tex]\text{Moles of Ar}=\frac{675.5g}{39.95g/mol}=16.91 mol[/tex]

Given mass of [tex]Cl_2[/tex] = 465.0 g

Molar mass of [tex]Cl_2[/tex] = 70.9 g/mol

Plugging values in equation 1:

[tex]\text{Moles of }Cl_2=\frac{465.0g}{70.9g/mol}=6.56 mol[/tex]

Total moles of gas in the tank = [16.91 + 6.56] mol = 23.47 mol

Mole fraction is defined as the moles of a component present in the total moles of a solution. It is given by the equation:

[tex]\chi_A=\frac{n_A}{n_A+n_B}[/tex]        .....(2)

where n is the number of moles

Moles of Ar = 16.94 moles

Total moles of gas in the tank = 23.47 mol

Putting values in equation 2, we get:

[tex]\chi_{Ar}=\frac{16.94}{23.47}\\\\\chi_{Ar}=0.722[/tex]

Total mole fraction of the system is always 1

Mole fraction of [tex]Cl_2[/tex] = [1 - 0.722] = 0.278

Raoult's law is the law used to calculate the partial pressure of the individual gases present in the mixture.

The equation for Raoult's law follows:

[tex]p_A=\chi_A\times p_T[/tex]                  .....(3)

where [tex]p_A[/tex] is the partial pressure of component A in the mixture and [tex]p_T[/tex] is the total partial pressure of the mixture

We are given:

[tex]\chi_{Ar}=0.722\\p_T=4.00atm[/tex]

Putting values in equation 3, we get:

[tex]p_{Ar}=0.722\times 4.00atm\\\\p_{Ar}=2.888atm[/tex]

We are given:

[tex]\chi_{Cl_2}=0.278\\p_T=4.00atm[/tex]

Putting values in equation 3, we get:

[tex]p_{Cl_2}=0.278\times 4.00atm\\\\p_{Cl_2}=1.112atm[/tex]

Answer:

Glass 1

Explanation:

Molarity is measured in moles of substance per liter.

For the sake of calculations, let's say that each glass contains 1 mole of juice and 1 liter after it is divided between the glasses. If you add an equal amount of water to glass 1 ( another liter), you now have:

Glass 1 = 1 mole / 2 liters = 0.5 M

Glass 1 = 1 mole/ 1 liter = 1 M

So glass 1 will have a lower molarity

Answer:

[tex]4.67\times 10^{-4}[/tex]

Explanation:

Given that,

The pH of a certain orange juice is 3.33.

We need to find the +ion concentration.

We know that,

[tex]pH=-log[H^+][/tex]

So,

[tex]3.33=-log[H^+]\\\\\[H^+=10^{-3.33}\\\\=4.67\times 10^{-4}[/tex]

So, the +ion concentraion is equal to [tex]4.67\times 10^{-4}[/tex].

Answer: The correct option is C (One of the fatty acid salts was unsaturated, and it completely isomerized under the reaction conditions).

Explanation:

Fats and oils belongs to a general group of compounds known as lipids. Fatty acids are weak acid and are divided into two:

--> Saturated fatty acids: These have NO double bonds in their hydrocarbon chain, and

--> Unsaturated fatty acids: These have one or more double bonds in their hydrocarbon chain.

SAPONIFICATION is defined as the process by which fats and oil is hydrolyzed with caustic alkali to yield propane-1,2,3-triol and the corresponding sodium salt of the component fatty acids. During this process, One hydroxide ion is required to hydrolyze one ester linkage of a triacylglycerol molecule. Because there are three ester linkages in a triacylglycerol, three equivalents of sodium hydroxide will be needed to completely saponify the triacylglycerol. This explains the reason why saponification of the triacylglycerol iresulted in four different fatty acid salts.

Chemistry and chemical reactions are not just limited to the laboratories but also the world around you.

Chemistry in Food Production:

Plants produce food for themselves through photosynthesis; which is a complex chemical reaction in itself. The chemical reaction that takes place in photosynthesis is the most common and vital chemical reaction. 

6 CO2 + 6 H2O + light → C 6H12O6 + 6 O2

Chemistry in Hygiene:

Right before you consume your food, you make it a point to wash your hands with soap. Isn’t it? The cleaning action of soap is based on its ability to act as an emulsifying agent. Soaps are fatty acids salts of sodium or potassium; produced by a chemical reaction called saponification. Soaps interact with the grease or oil molecule, which, in turn, results in a cleaner surface.

The Chemistry of an Onion:

Ever wondered why you shed tears while chopping an onion? This also happens because of the underlying chemistry concepts. As soon as you slice an onion, sulfenic acid is formed from amino acid sulfoxides. Sulfenic acid is responsible for the volatile gas, propanethiol S-oxide, that stimulates the production of tears in the eyes.

Chemistry in Baking:

Who does not like to eat fluffy freshly baked bread? Baking soda is an efficient leavening agent. The addition of baking soda to food items before cooking leads to the production of carbon dioxide (CO2); which causes the foods to rise. This whole process of rising of baked good is called chemical leavening.

Chemistry in Food Preservatives:

In case you ever read the ingredients on the bottle of ketchup, jams or pickles, you might be surprised to see a never-ending list of chemicals. What are they? These chemicals are called food preservatives; which delay the growth of microorganisms in foods. The chemical food preservatives not only prohibit the growth of bacteria, virus, fungi but also hinder the oxidation of fats, which is responsible for making the foods rancid. The most common chemical food preservatives are sodium benzoate, sorbic acid, potassium sorbate, calcium sorbate, sodium sorbate, propionic acid, and the salts of nitrous acid.

Chemistry in Digestion

The moment you put food in your mouth, a number of different chemical reactions start in your digestive tract. Saliva contains the enzyme amylase, which is responsible for breaking down carbohydrates, the stomach starts producing hydrochloric acid, the liver releases bile and the list of compounds released during digestion goes on. How do they work? All these enzymes undergo chemical reactions so that proper digestion, as well as assimilation of the food, occurs.

The Working of a Sunscreen

Before going out on a sunny day, you make it a point to wear sunscreen. Even the principle, behind the working of a sunscreen, has a chemistry background. The sunscreen uses a combination of organic and inorganic compounds to act as a filter for incoming ultraviolet rays. Sunblocks, on the other hand, scatter away UV light; so that it is unable to penetrate deep into the skin. Sunblocks contain complex chemical compounds like zinc oxide or titanium oxide, which prevent the UV rays to invade deeper into the skin.

Chemistry in Rust Formation

With time, your iron instruments start developing an orange-brown flaky coating called rust. The rusting of iron is a type of oxidation reaction. The atoms in the metal iron undergo oxidation and reduction; causing rusting. The formation of verdigris on copper and the tarnishing of silver are also the other everyday examples of chemical reactions. The chemical equation underlying rusting is:

Fe + O2 + H2O → Fe2O3. XH2O

Hope it helps.

Answer:

physical change because the gaseous water is chemically the same as the liquid

Explanation:

Matter can be defined as anything that has mass and occupies space. Any physical object that is found on earth is typically composed of matter. Matter are known to be made up of atoms and as a result has the property of existing in states.

Generally, matter exists in three (3) distinct or classical phases and these are; solid, liquid and gas.

A physical change can be defined as a type of change that only affects the physical form of a chemical substance (matter) without having any effect on its chemical properties. Thus, a physical change would only affect the physical appearance and properties of a chemical substance (matter) but not its chemical properties.

This ultimately implies that, a physical change result in a change of matter from one form or phase (liquid, solid or gas) to another without a corresponding change in chemical composition.

Hence, the boiling of water is considered to be a physical change because the gaseous water is chemically the same as the liquid i.e there isn't any changes in chemical composition of water when boiling.

Step 1: Represent a molecular formula.

[tex]\text{molecular formula} = (\text{CH}_{2}\text{N}_{2})_{n}[/tex]

Step 2: Calculate the empirical mass.

empirical mass = (12.0 g/mol × 1) + (1.0 g/mol × 2) + (14.0 g/mol × 2)

empirical mass = 42.0 g/mol

Step 3: Divide the molecular mass by the empirical mass.

[tex]n = \frac{\text{molecular mass}}{\text{empirical mass}}[/tex]

[tex]n = \frac{\text{126.0}}{\text{42.0}}[/tex]

[tex]n = 3[/tex]

Step 4: Multiply the subscripts by the value of n to obtain the molecular formula.

[tex]\text{molecular formula} = (\text{CH}_{2}\text{N}_{2})_{3}[/tex]

[tex]\boxed{\text{molecular formula} = \text{C}_{3}\text{H}_{6}\text{N}_{6}}[/tex]

[tex]\\[/tex]

#ILoveChemistry

#ILoveYouShaina

Answer:

Draw the structures and provide the names of all the isomeric alcohols that have the molecular formula C4H10O.

Draw the structures of (a) 6-methyl-3-heptanol and (b) trans-2-methylcyclohexanol

Explanation:

Isomers are compounds with the same molecular formula but different structural arrangements of atoms.

The given molecule is:

C4H10O.

The possible isomeric alcohols structures are shown below:

Structure of (a) 6-methyl-3-heptanol:

The root word -hept indicates that the main carbon chain has seven carbons.

-ol suffix indicates the presence of alcohol functional group at third carbon.

The 6-methyl prefix indicates the presence of methyl group as the substituent at the sixth position of the main carbon chain.

The structure of 6-methyl-3-heptanol is shown below:

The structure of trans-2-methyl cyclohexanol is shown below:

Answer:

Farmers spray to mitigate crop damage caused by pests. A pest is any biological organism, including weeds, pathogens, and arthropods, that interferes with the production of crops affecting quality and/or yield. ... Pesticides work in many different ways by affecting their target, whether it be a weed, pest, or disease.

Explanation:

this is my answer❤︎

Answer:

B

Explanation:

hợp chất nào có khả năng là hợp chất ion cao nhất ?

A Al2O3?

B

Answer:

No of protons is equal to the atomic number.

Answer:

atomic number

Explanation:

Answer:

The answer is the explanation.

Explanation:

The acetic acid, CH3COOH, reacts with calcium hydroxide, Ca(OH)2, producing acetate ion, CH3COO- and water as follows:

2CH3COOH + Ca(OH)2 → 2CH3COO- + 2H2O + Ca²⁺

That means the moles of acetic acid decrease whereas the moles of  acetate ion are increased. The ratio of [CH3COOH] / [CH3COO-] is different.

As a base is added, the concentration of H3O+ decreases increasing the pH.

That means:

TRUE A. The number of moles of CH3COOH will decrease.

FALSE B. The number of moles of CH3COO- will decrease.

TRUE C. The equilibrium concentration of H3O will decrease.

FALSE D. The pH will decrease.

FALSE E. The ratio of [CH3COOH] / [CH3COO-] will remain the same.

Answer:

F-

Explanation:

Since Fluorine needs one more electron to reach a full octet, it takes in 1 more electron to become an anion. Therefore, with the extra negative charge from the 1 electron, a Fluoride ion has a charge of -1.

Hope this helped!

Answer:

F_

Explanation:

the symbol or formula

is F_

Answer:

The problem of energy exchange between waves and particles, which leads to energization of the latter, in an unstable plasma typical of the radiation belts. The ongoing Van Allen Probes space mission brought this problem among the most discussed in space physics. A free energy which is present in an unstable plasma provides the indispensable condition for energy transfer from lower energy particles to higher-energy particles via resonant wave-particle interaction. This process is studied in detail by the example of electron interactions with whistler mode wave packets originated from lightning-induced emission. We emphasize that in an unstable plasma, the energy source for electron energization is the energy of other particles, rather than the wave energy as is often assumed. The way by which the energy is transferred from lower energy to higher-energy particles includes two processes that operate concurrently, in the same space-time domain, or sequentially, in different space-time domains, in which a given wave packet is located. In the first process, one group of resonant particles gives the energy to the wave. The second process consists in wave absorption by another group of resonant particles, whose energy therefore increases. We argue that this mechanism represents an efficient means of electron energization in the radiation belts.

Explanation:

Fun facts:

In the process of energy transfer between two groups of particles both processes operate simultaneously, and if the lower energy part of plasma distribution gives energy to the wave while the higher‐energy part absorbs the wave enrgy, then the wave‐mediated energy transfer from lower energy particles to higher‐energy ...

Answer:

5 atoms form one formula unit of Fe2O3

Explanation:

2 atoms of Fe (Iron)

and 3 atoms of O ( Oxygen)

so total = 3 + 2

= 5

Answer:

fe203 the right answer is thus

Answer:

CH 2 CH 3 CHCH = C6H5 + 5 Hydrogen Atoms

I hope I helped you.

Deepest apologies if I was wrong!

Bye!

~ Myaka O.

Answer:

Carbon is dull, have a low density, and are poor conductors of heat.

Explanation:

Carbon is a non-metal, therefore bearing properties of a non-metal element.

Answer:

-0.08 °C

Explanation:

We can solve this problem by using Charles' law, which states that at constant pressure:

Where in this case:

We input the data:

And solve for T₂:

Finally we convert 273.08 K to Celsius: