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Eddi Din [679]
3 years ago
10

1.)If you are given the number of particles in a substance sample, what is the first step you should take to determine how many

grams are present in that sample?
Find the molar mass of the substance.

Convert the grams to particles.

Convert the moles to mass.

Convert the number of particles to moles.


2.)Phosphoric acid, which is a component of many soft drinks, has a molar mass of 98.00 grams per mole. A sample of phosphoric acid contains 3.1 percent hydrogen, 31.6 percent phosphorus, and 65.3 percent oxygen by mass. What is the molecular formula of phosphoric acid?

HPO

H2PO2

H3PO4

H6P2O8


3.)Which of the following cannot occur in a chemical reaction?

New atoms are created.

Heat is released.

Light is produced.

Temperature is changed.


4.)What information do the coefficients in a balanced chemical equation tell you?

The amount of energy from the products.

The ratios of the number of moles of each substance that react and that are produced.

The physical states of the compounds reacting.

The elements involved in the reaction.


5.)Which law states that, in chemical reactions, the total mass of reactants must equal the total mass of the products?

conservation of molecules

conservation of energy

conservation of mass

conservation of elements


6.)How do you know if an equation is balanced?

All substances in the equation have written coefficients.

The reactant and product coefficient totals are equal.

The number of atoms for every element is equal on both sides of the equation.

All coefficients are divisible by two.


7.)In a reaction, 15 moles of carbon dioxide are produced from 5 moles of iron (III) oxide and 15 moles of carbon monoxide. What is the mole ratio of carbon dioxide to carbon monoxide?

15:5

5:15

1:3

1:1


8.)What is the mole ratio of C3H8 to carbon dioxide in the following equation?

C3H8 + 5O2 à 3CO2 + 4H2O

3:03

11:06

1:03

24:06:00


9.)Two moles of hydrogen gas is reacted with oxygen gas to produce water in this reaction:

2 H2 + O2 → 2 H2O

In the lab you actually made 33.1 grams of water. What is the percent yield?

108.10%

91.80%

5.50%

100%
Chemistry
1 answer:
alekssr [168]3 years ago
8 0

Answer:

1-Find the molar mass of the substance.

2-H3PO4

3-New atoms are created.

4-The ratios of the number of moles of each substance that react and that are produced.

5-conservation of mass

6-The number of atoms for every element is equal on both sides of the equation.

7-1:1

8-1:03

9-5.50%

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Answer:

that is all I know sorry hope that may help you :)

Explanation:

Indicator is a substance which shows different colors in acidic and basic medium. Indicators can be natural (derived from natural sources) or artificial ( man-made) for example :

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* Turmeric solution does not show change in color (remains yellow) in acidic solution and turns red in basic solution.

8 0
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Cytotoxic t cells can attack target cells with which chemical weapons?
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Answer:

secrete cytotoxic substance which triggers apoptosis of target cell.

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What would you use to mesuasee the height of the tree
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7 0
3 years ago
An interpenetrating primitive cubic structure like that of CsCl with anions in the corners has an edge length of 664 pm. If the
san4es73 [151]

Answer:

the ionic radius of the anion r^- = 312.52 \ pm

Explanation:

From the diagram shown below :

The anion Cl^- is located at the corners

The cation Cs^+ is located at the body center

The Body diagonal length =  \sqrt{3 \ a }

∴ 2 \ r^+ \ + 2r^- \ = \sqrt{3 \ a}  \\ \\ r^+ +r^- = \frac{\sqrt{3}}{2} a

Given that :

\frac{r^+}{r^-} =0.84   (i.e the  ratio of the ionic radius of the cation to the ionic radius of

                 the anion )

0.84r^- \ + r^- \ = \frac{\sqrt{3}}{2}a  \\ \\  1.84 r^- = \frac{3}{2}a \\ \\ r^- = \frac{\sqrt{3}}{2*1.84}a

Also ; a =  664 pm

Then :

r^- = \frac{\sqrt{3} }{2*1.84}*664 \ pm\\ \\ r^- = 312.52 \ pm

Therefore,  the ionic radius of the anion r^- = 312.52 \ pm

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3 years ago
Phosphorus has three electrons in its 3p sublevel and sulfur has four. Phosphorus should have the lower ionization energy but it
Nadya [2.5K]

Answer:

B

Explanation:

First of all it is important to know that a half filled orbital is particularly stable. In phosphorus all the electrons occur singly in the 3p sublevel minimizing inter electronic repulsion hence it is more difficult to remove an electron from this energetically stable arrangement. In sulphur, electrons are paired in one of the 3p orbitals thereby lowering the energy of that level due to instability caused by interelectronic repulsion between two electrons in the same orbital.

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