Question 1

Which of the following is NOT a common sign that a chemical reaction has occurred?

Accepted Answer

Dissolving sugar in water

Question 2

Which of the following best describes the Law of Conservation of Mass as it applies to chemical reactions?

Accepted Answer

The total mass of reactants must equal the total mass of products

Question 3

Which symbol in a chemical equation indicates that a substance is dissolved in water?

Accepted Answer

$$ (aq) $$

Question 4

Which of the following elements is DIATOMIC in its natural state?

Accepted Answer

Oxygen

Question 5

What is the balanced chemical equation for the combustion of charcoal (carbon) in oxygen to form carbon dioxide?

Accepted Answer

$$ \mathrm{C} (s) + \mathrm{O}_2 (g) \rightarrow \mathrm{CO}_2 (g) $$

Question 6

Balance the following equation: $$ \mathrm{Al} (s) + \mathrm{CuCl}_2 (aq) \rightarrow \mathrm{AlCl}_3 (aq) + \mathrm{Cu} (s) $$

Accepted Answer

$$ 2\mathrm{Al} (s) + 3\mathrm{CuCl}_2 (aq) \rightarrow 2\mathrm{AlCl}_3 (aq) + 3\mathrm{Cu} (s) $$

Question 7

Which of the following best explains why chemical equations must be balanced?

Accepted Answer

To satisfy the Law of Conservation of Mass

Question 8

What is the correct balanced equation for the formation of water from hydrogen and oxygen?

Accepted Answer

$$ 2\mathrm{H}_2 (g) + \mathrm{O}_2 (g) \rightarrow 2\mathrm{H}_2\mathrm{O} (l) $$

Question 9

A student observes a reaction where a yellow solid forms when two clear solutions are mixed. What is the best explanation for this observation?

Accepted Answer

A precipitate has formed, indicating a chemical reaction

Question 10

Which of the following equations is balanced?

Accepted Answer

$$ 2\mathrm{NaOH} + \mathrm{H}_2\mathrm{SO}_4 \rightarrow \mathrm{Na}_2\mathrm{SO}_4 + 2\mathrm{H}_2\mathrm{O} $$

Question 11

Which of the following is a correct representation of a gas in a chemical equation?

Accepted Answer

$$ (g) $$

Question 12

Balance the following equation: $$ \mathrm{C}_2\mathrm{H}_5\mathrm{OH} + \mathrm{O}_2 \rightarrow \mathrm{CO}_2 + \mathrm{H}_2\mathrm{O} $$

Accepted Answer

$$ \mathbf{C}_2\mathrm{H}_5\mathrm{OH} + 3\mathrm{O}_2 \rightarrow 2\mathrm{CO}_2 + 3\mathrm{H}_2\mathrm{O} $$

Question 13

Which of the following best describes why oxygen is written as $$ \mathrm{O}_2  in $$chemical equations?

Accepted Answer

Oxygen is diatomic in its natural state

Question 14

A reaction produces a color change, heat, and bubbles. What does this indicate?

Accepted Answer

A chemical reaction has likely occurred

Question 15

Balance the following equation: $$ \mathrm{Mg} + \mathrm{O}_2 \rightarrow \mathrm{MgO} $$

Accepted Answer

$$ 2\mathrm{Mg} + \mathrm{O}_2 \rightarrow 2\mathrm{MgO} $$

Question 16

Which of the following is a correct statement about balancing chemical equations?

Accepted Answer

The number of atoms of each element must be the same on both sides of the equation

Question 17

Which of the following is the correct balanced equation for the reaction of sodium sulfate with calcium nitrate to produce sodium nitrate and calcium sulfate?

Accepted Answer

$$ \mathrm{Na}_2\mathrm{SO}_4 + \mathrm{Ca(NO}_3)_2 \rightarrow 2\mathrm{NaNO}_3 + \mathrm{CaSO}_4 $$

Chemical Reactions and Balancing Chemical Equations: Study Notes

Guida di studio - Domande di pratica

Study guide - Flashcard