Question 1

Which of the following best describes a homogeneous mixture, and which example below fits this classification?

Accepted Answer

A mixture with a uniform composition throughout; brass (copper and zinc)

Question 2

Which of the following is a chemical change?

Accepted Answer

Burning a piece of wood to produce heat, ashes, carbon dioxide, and water vapor

Question 3

Which of the following statements about compounds is correct?

Accepted Answer

A compound contains two or more elements combined in a fixed ratio.

Question 4

Which of the following is an example of a physical property?

Accepted Answer

Copper is an excellent conductor of heat and electricity.

Question 5

Which of the following equations represents a balanced chemical reaction?

Accepted Answer

$$2H_2 + O_2$ \rightarrow 2H_2O$$

Question 6

Which of the following is NOT a sign of a chemical reaction?

Accepted Answer

A change in state from solid to liquid

Question 7

A student mixes two clear solutions and observes the formation of a yellow solid. What type of chemical reaction has most likely occurred?

Accepted Answer

Double replacement reaction

Question 8

Which of the following best describes the difference between an element and a compound?

Accepted Answer

An element contains only one type of atom, while a compound contains two or more elements chemically combined.

Question 9

Which of the following is a decomposition reaction?

Accepted Answer

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

Question 10

Which of the following best describes a combustion reaction?

Accepted Answer

A carbon-containing compound reacts with $$O_2 to $$produce $$CO_2$$, $$H_2O$$, and energy.

Question 11

Which of the following is an example of a heterogeneous mixture?

Accepted Answer

A mixture of water and copper metal

Question 12

Which of the following is a physical change?

Accepted Answer

Ice melting in the sun

Question 13

Which of the following best describes the state of matter for a gas?

Accepted Answer

Indefinite shape and indefinite volume

Question 14

Which of the following is a single replacement reaction?

Accepted Answer

$$Zn (s) + 2HCl (aq) \rightarrow $$ZnCl_2$$ (aq) + H_2$ (g)$$

Question 15

Which of the following is a correct statement about mixtures?

Accepted Answer

Mixtures can be separated by physical methods.

Question 16

Which of the following is a double replacement reaction?

Accepted Answer

$$BaCl_2 (aq) + K_2SO_4 (aq$$) \rightarrow $$BaSO_4 (s) + 2$$KCl (aq)$$

Question 17

Which of the following is a sign that a chemical reaction has occurred?

Accepted Answer

A solid forms when two solutions are mixed

Question 18

Which of the following best describes a physical change?

Accepted Answer

A change in state or shape without changing the substance's identity

Question 19

Which of the following is an example of a compound?

Accepted Answer

Table sugar ($$C_{12}H$$_{22}$$O_{11}$)

Classification of Matter and Chemical Reactions: GOB Chemistry Study Notes

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