Answer:
Atomic theory is the scientific theory that matter is composed of particles called atoms.
isotopes are variants of a particular chemical element which differ in neutron number, and consequently in nucleon number.
to calculate the atomic mass of a single atom of an element, add up the mass of protons and neutrons.
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Explanation:
Convert each of the following masses to the units requested.
a. 0.765g to kilograms
b. 1.34 g to milligrams
c. 34.2mg to grams
Answer:
a) 0.000765kg
b) 1340mg
c) 0.0342g
Explanation:
a) 1000g = 1kg
0.765g= 0.765/ 1000
= 0.000765g
b) 1g = 1000mg
1.34g = 1.34 × 1000
= 1340mg
c) 1000mg = 1g
34.2mg = 34.2/1000
= 0.0342g
A substance can change into a new kind of molecule when:
Answer:
Chemical changes cause a substance to change into an entire substance with a new chemical formula. Chemical changes are also known as chemical reactions. The “ingredients” of a reaction are called reactants, and the results are called products.
Hope it helps
Help plzzzzz ASAP!!!!!!!
Answer:
3. The total number of protons and neutrons in an atom is its mass number.
4. The mass number of a helium atom with 2 protons and 2 neutrons is 4.
5. A beryllium atom with 4 protons and a mass number of 9 has 5 neutrons.
6. The chemical symbol is Ne. The atomic number is 10. The mass number is 22.
7. Neon-22
8. Not enough information
Consider the following unbalanced equation.
Ca(OH)2 + (NH2)2SO4 → CaSO4 + NH3 + H2O
Help for 70 points please explain why too.
Answer:
1 Ca(OH)2 + 1 (NH4)2SO4 ---> 1 CaSO4 + 2 NH3 + 2 H2O
Explanation:
The photo I attached should make more sense as an explanation.
When balancing equations, the first and most important step is to count the # of each type of element on each side.
In this problem there are 5: Ca, O, H, N, and S.
Once you do that you can begin balancing.
Here is the initial tally for the elements in this problem:
On the left.....
Ca - 1
N - 2
S - 1
O - 6
H - 10
On the right.....
Ca - 1
N - 1
S - 1
O - 5
H - 5
Looking at these values, we can see N, O, and H all need adjusting the right side. You should never start balancing with O or H unless they are the only elements that need adjusting. They usually balance out with the rest of your work or with water in the end.
So given all of that, you should start balancing with N on the right. Giving NH3 a coefficient of 2 will change the number of Nitrogen atoms on the right to 2. Be careful though! It will also change the number of Hydrogen atoms from 5 to 8 (because (2*3) =6 and 6+2 =8).
Let's tally our numbers again.
On the left..... (these should be unchanged)
Ca - 1
N - 2
S - 1
O - 6
H - 10
On the right.....
Ca - 1
N - 2
S - 1
O - 5
H - 8
Okay, now we see only O and H need adjusting on the right. Luckily there is H2O so we can do that without impacting the number of other atoms.
Give H2O a coefficient of 2 and count the number of atoms on the right again.
On the right.....
Ca - 1
N - 2
S - 1
O - 6 (because 4 from CaSO4 plus 2 from 2H2O = 6)
H - 10 (6 from NH3 plus 4 from 2H2O = 10)
Do these numbers match what you have on the the left side of the equation? Yes! It is balanced so you do not need to adjust anymore. Your coefficients in the answer will be 1-1-1-2-2.
While designing his recording studio, Brian was trying to determine what type of surface he should use for his studio walls. He wanted to be able to produce clear, crisp, sound. So he needed a surface that wouldn't cause his music to echo. What type of surface should Brian use for his studio walls?
Answer: Acoustic Foam.
Explanation:
Acoustic Foam: This is a kind of material, which is commonly known as it called a Studio Foam, it has a kind of wedge or pyramid shape that plays a big role in absorbing sound. Brian would have to use acoustic foam by placing them round the walls and ceiling as this would stop any echoing sound and in return give a crisp and clear sound when music is been played it the studio.
What is the process whereby scientists check each other’s work?
A. defining the audience
B. conferencing
C. peer reviewing
D. writing
Answer:
peer reviewing
Explanation:
Its peer reviewing because there peers and there reviewing eachothers work
The process whereby scientists check each other’s work is peer reviewing.
What is peer group?Peer group are the groups of people of same age, same background with same interest.
In the peer reviewing process group of members will check, evaluate and correct each others work, which in turn help the members of the group to update their work.
Hence, option (c) is correct i.e. peer reviewing is the process whereby scientists check each other’s work.
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What information does a subscript in a chemical formula provide? Choose all that apply. * The charge of that atom while in the compound How many of each atom are present in the compound How many valence electrons each element has while in the compound How many valence electrons each element starts with In ionic, the simplified ratio of atoms in relation to each other
Answer:
B. How many of each atom are present in the compound
D. the simplified ratio of atoms in relation to each other
Explanation:
In a chemical formula, chemical elements or atoms are represented by a chemical symbol for example Fe for iron and Na for sodium, and the number of each atom is represented by a subscript such as CO2, where 2 is a subscript representing 2 atoms of oxygen.
A subscript represents the number of each atom in the compound and the simplified ratio of atoms in relation to each other. The simplified ratio of atoms in relation to each other means subscript shows the contribution of both the atoms in the compound, for example: N2 + 3H2 => 2NH3, it means the subscript showing the ratio or proportionate of atoms that is 2:2 for both nitrogen and hydrogen.
The subscript is always written below and to the right of the chemical symbol.
Hence, the correct answer is "B. How many of each atom are present in the compound and D. the simplified ratio of atoms in relation to each other"
During the Metric Olympics yesterday, Molly's long jump was 118.3 cm. Christy accidentally recorded her results in inches. She jumped 51.18 inches. Can you help... Who won the long jump? Christy won by about 30 cm Christy won by about 30 cm Molly won by about 25 cm Molly won by about 25 cm Christy won by about 12 cm Christy won by about 12 cm Molly won by about 10 cm
Answer: Christy won Molly by 12cm
Explanation:
Ist step
Molly's ;ong jump was 118.3cm
Christy long jump was 51.18inches
2nd Step
we change christy score to cm so we can compare
1 inch = 2.54cm.
therefore 51.18 inches = 51.18 x 2.54= 129.9972cm
Christy won molly by 129.9971cm-118.3cm=11.69 rounded to 12cm
Christy won Molly by 12cm
A student has a container of sand and sugar. What characteristic could be used to separate the mixture?
Answer:
Sugar will dissolve, so water.
Explanation:
Sugar is a bicubacle food source you could say, sand will not evaporate or dissolve in the water since it is not a 3c2e source. Using water will seperate them.
Answer: Heat
Explanation:
Because is you put water and sand in a container you can separated by boiling the water and all the water would evaporate and the sand would stay.
Which is the name of O3?
dioxide
oxygen
trioxygen
monoxide
The answer is C, Trioxygen
The name for O₃ molecule is trioxygen as it is made up of three oxygen atoms.
What is an atom?An atom is defined as the smallest unit of matter which forms an element. Every form of matter whether solid,liquid , gas consists of atoms . Each atom has a nucleus which is composed of protons and neutrons and shells in which the electrons revolve.
The protons are positively charged and neutrons are neutral and hence the nucleus is positively charged. The electrons which revolve around the nucleus are negatively charged and hence the atom as a whole is neutral and stable due to presence of oppositely charged particles.
Atoms of the same element are similar as they have number of sub- atomic particles which on combination do not alter the chemical properties of the substances.
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How do minerals differ from ores?
Ores: metal/coal (iron, gold, coal)
Mineral: not metal, (Granite, limestone,
Which food molecules are outside of the tube
Answer:
Absorption
Explanation:
I think from Quizlet
Match the terms below to the correct definitions
3. Atom
1. The mass on the periodic table.
b. Electrons
2. Region surrounding the nucleus where electrons are found.
C. Protons
3. Positively charged center of an atom.
d. Neutrons
4. Particles that differ in number between isotopes.
e. Electron
cloud
5. Vertical column in the periodic table.
1. Nucleus
6. Positively charged particles in an atom.
R. Quark
7. Negatively charged particles in the outermost energy levels of the electron cloud.
8. Table that organizes the elements by properties.
9. Atoms of the same element that have different masses.
h. Atomic
number
1. Mass number
10. Smallest known particle that makes up protons and neutrons.
j. Average
atomic mass
11. All elements in the same one of these has the same number of energy levels in
their electron cloud.
k. Isotopes
12. The smallest form of matter that still retains the properties of an element.
1. Valence
electrons
13. Negatively charged particles in an atom.
m. Group
14. The sum of protons and neutrons in an atom.
n. Period
15. Represents the identity of an element.
o. Periodic
Table
Answer:
Explanation:
1=i
4=d
5=m
6=c
8=o
9=j
10=a
13=b
14=h
15=l
Theses are the ones i knew
Element X has two naturally occurring isotopes. The isotope with mass 62.93 amu has a
relative abundance of 69.2%. The isotope with mass 64.93 amu has a relative
abundance of 30.8%. Calculate the average atomic mass of Element X. What is the
identity of Element X?
Calculate the molarity of a NaOH solution that is prepared by diluting 100mL of 0.20M NaOH with 150mL of H2O.
Molarity of solution = 0.08 M
Further explanationMolarity shows the number of moles of solute in every 1 liter of solution or mmol in each ml of solution
[tex]\tt M=\dfrac{n}{V}[/tex]
Where
M = Molarity
n = number of moles of solute
V = Volume of solution
mol of NaOH[tex]\tt mol=0.2~M\times 100~ml=20~mlmol=0.02~mol[/tex]
molarityVolume of solution = 100 ml + 150 ml = 250 ml
[tex]\tt M=\dfrac{0.02~mol}{0.250~L}=0.08[/tex]
Which of the following is true about metals?
A. They are usually less reflective in luster than metalloids.
B.
They are usually better conductors than nonmetals.
C. They are usually less malleable than nonmetals.
D.
They are usually more brittle than metalloids.
A student places a small amount of water in a glass dish and then carefully places a small paperclip on the surface of the water. The paperclip floats. What happens if the student adds a drop or two of dish soap to the water?
Answer:
Adding soap would cause the paper clip to fall through the water and onto the base of the dish because soap is a surfactant.
Explanation:
The concept surface tension is used here to determine what happens to the paperclip when a drop of dish soap is added to the water. Here the paperclip sink into the water.
What is surface tension?The property exhibited by the surface of a liquid in order to resist the action of an external force because of the cohesive nature of the molecules is known as the surface tension. Due to this property the surface of a liquid behaves as an extended elastic membrane.
The paperclip float on water because of the high surface tension as the water molecules at the surface are strongly attracted among themselves. But on adding one or two drops of dish soap to water causes the paperclip to sink.
The addition of the drops of dish soap to the water weakens the attraction among the water molecules and thereby lowers the surface tension. As a result of this the surface film disappears and the paperclip sink into the water.
Thus the paperclip fall into the water when a drop of dish soap is added to the water.
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Round the value 44.981
Answer: 45
Explanation: it would be 45 bc if the value is 5 and over the number goes up and if it is lower than 5 it would stay the same.
Answer:
45 is the answer
Explanation:
Which statement describes a molecule that has a trigonal pyramidal molecular shape?
The molecule has a trigonal planar electron domain geometry with one lone pair.
O The molecule has a tetrahedral electron domain geometry with one lone pair.
O The molecule has a trigonal planar electron domain geometry with two lone pairs.
O The molecule has a tetrahedral electron domain geometry with two lone pairs.
The statement describes a molecule that has a trigonal pyramidal molecular shape is "The molecule has a trigonal planar electron domain geometry with two lone pairs".
So, option C is correct one.
What is difference between shape and geometry of the molecule?In finding geometry of the molecule, lone pairs and bond pairs both are included but in finding shape of the molecule only bond pairs are are involve.
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Answer:C
Explanation: Took the test
Calculate the volume in milliliters of a 5.05-g sample of a solid with a density of 3.25 g/mL.
Answer:
The answer is 1.55 mLExplanation:
The volume of a substance when given the density and mass can be found by using the formula
[tex]volume = \frac{mass}{density} \\ [/tex]
From the question
mass = 5.05 g
density = 3.25 g/mL
We have
[tex]volume = \frac{5.05}{3.25} \\ = 1.5538461...[/tex]
We have the final answer as
1.55 mLHope this helps you
Describe the transmission of sound through solids,liquids,and gases.
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if atom X has 6 protons,6 neutrons and 6 electrons and aton Z has 6 protons,7neutrons and 6 electrons,atom x and atom z are isotopes of the element
Why Hund's Rule is called maximum spin multiplicity rule?
Answer:
The rule states that for a given electron configuration, the lowest energy term is the one with the greatest value of spin multiplicity. This implies that if two or more orbitals of equal energy are available, electrons will occupy them singly before filling them in pair
Explanation:
What is the density of nitrogen gas if 0.256g occupies a volume of 100mL?
Answer:
The answer is 0.00256 g/mLExplanation:
The density of a substance can be found by using the formula
[tex]density = \frac{mass}{volume} \\ [/tex]
From the question we have
[tex]density = \frac{0.256}{100} \\ [/tex]
We have the final answer as
0.00256 g/mLHope this helps you
Kinetic molecular theory states... (choose all that apply)
A. There is a chemical change when a solid melts to a liquid.
B. Particles that make up matter have kinetic energy.
C. Particles that make up matter are always in motion
Surface water is found in oceans, lakes, reservoirs, streams, rivers,and glaciers. Lakes, rivers, and reservoirs are where humans obtain most of the surface water they use. Aquifers are an underground source of water that humans also use.
I'd is 643461717 and password is dynamo
Answer:bet
Explanation:
2. Ultraviolet radiation has a frequency of 6.8 x 10'5Hz. Calculate the energy, in
joules, of the photon.
Answer:
[tex]E=4.5\times 10^{-18}\ J[/tex]
Explanation:
It is given that, the frequency of Ultraviolet radiation is [tex]6.8\times 10^{15}\ Hz[/tex]
We need to find the energy of the photon. The formula for the energy of a photon is given by :
[tex]E=hf\\\\\text{Where h is Planck's constant}\\\\E=6.63\times 10^{-34}\times 6.8\times 10^{15}\\\\E=4.5\times 10^{-18}\ J[/tex]
So, the energy of the photon is [tex]4.5\times 10^{-18}\ J[/tex].
Where do we live a.Troposphere b.Thermosphere c. Mesosphere D.Stratosphere
Answer:
troposphere
Explanation:
Answer:
Hello!!! Princess Sakura here ^^
Explanation:
We live in the troposphere since 99% of the water vapor in the atmosphere is found here.
where is lithium used in the body?
Answer:
Lithium is a naturally occurring alkali metal, which living organisms ingest from dietary sources and which is also present in trace amounts in the human body. In much higher concentrations, lithium is effective as a medication for mania and mood swings including manic depressive disorders