Q: How many atoms of sulfur are present in $$2.00$$ moles of sulfur?

$$1.20 \times 10$$^{24}$$ atoms

Question 1

Which of the following best describes Avogadro's number and its significance in chemistry?

Accepted Answer

It is the number of particles (atoms, molecules, or ions) in one mole of a substance, equal to $$6.02 	imes 10$$^{23}$$.

Question 2

A sample contains $$24$$ cans of soda. This is equivalent to which of the following terms?

Accepted Answer

A case

Question 3

How many atoms of sulfur are present in $$2.00$$ moles of sulfur?

Accepted Answer

$$1.20 	imes 10$$^{24}$$ atoms

Question 4

What is the molar mass of sodium (Na)?

Accepted Answer

$$22.99 g/$$mol

Question 5

Calculate the molar mass of lithium carbonate, $$\mathrm{Li_2CO_3}.$$

Accepted Answer

$$73.89 g/$$mol

Question 6

A patient is prescribed $$0.500$$ moles of $$\mathrm{C_6H_{12}O_6$} ($$glucose). What is the mass of glucose required? (Molar mass of $$\mathrm{C_6H_{12}O_6$} is$$ $$180.16 g/$$mol)

Accepted Answer

$$90.08 g$$

Question 7

Which of the following is an example of a chemical change?

Accepted Answer

Tarnishing of silver to form $$\mathrm{Ag_2S}$$

Question 8

What type of chemical reaction is represented by the equation $$2\mathrm{H_2$}(g) + \mathrm{O_2$}(g) \rightarrow 2\mathrm{H_2O}(g)$$?

Accepted Answer

Combination (synthesis)

Question 9

Which of the following best describes an exothermic reaction?

Accepted Answer

A reaction that releases heat to the surroundings

Question 10

A $$12.01 g $$sample of carbon contains how many moles of carbon atoms?

Accepted Answer

$$1.00$$ mole

Question 11

Which of the following is the correct balanced equation for the rusting of iron?

Accepted Answer

$$4\mathrm{Fe} + 3\mathrm{O_2$} \rightarrow 2\mathrm{Fe_2O_3}$$

Question 12

Which of the following statements about oxidation and reduction is correct?

Accepted Answer

Oxidation is the loss of electrons and reduction is the gain of electrons.

Question 13

A reaction in which two compounds exchange ions to form two new compounds is called:

Accepted Answer

Double replacement reaction

Question 14

Which of the following best describes the role of a catalyst in a chemical reaction?

Accepted Answer

It lowers the activation energy, increasing the reaction rate.

Question 15

How many grams of $$\mathrm{NaCl}$$ are present in $$2.00$$ moles? (Molar mass of $$\mathrm{NaCl} is$$ $$58.44 g/$$mol)

Accepted Answer

$$116.88 g$$

Question 16

Which of the following is a decomposition reaction?

Accepted Answer

$$2\mathrm{HgO}(s) \rightarrow 2\mathrm{Hg}(l) + \mathrm{O_2$}(g)$$

Question 17

Which of the following is the correct molar mass for $$\mathrm{C_2H_6O} ($$ethanol)?

Accepted Answer

$$46.08 g/$$mol

Question 18

If $$1.00$$ mole of $$\mathrm{C_6H_{12}O_6$}$$ contains $$6.02 	imes 10$$^{23}$$ molecules, how many hydrogen atoms are present in 1.00$ mole of glucose?

Accepted Answer

$$7.22 	imes 10$$^{24}$$

Question 19

Which of the following best describes the energy profile of an endothermic reaction?

Accepted Answer

The products have higher energy than the reactants.

Chemical Quantities and Chemical Reactions: Study Notes

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