Q: Which of the following statements about energy units is correct?

$$1 \text{ kcal} = 4184 \text{ J}$$

Question 1

Which of the following best describes a heterogeneous mixture?

Accepted Answer

A mixture in which the components are not evenly distributed and can be visibly distinguished.

Question 2

Which of the following is an example of a pure substance?

Accepted Answer

Magnesium

Question 3

A student mixes 88 g of glucose with water to make a solution. Which term best describes the resulting mixture?

Accepted Answer

Homogeneous mixture

Question 4

Which of the following is a physical process that can be used to separate the components of a mixture?

Accepted Answer

Distillation

Question 5

Which of the following statements about energy units is correct?

Accepted Answer

$$1 	ext{ kcal} = 4184 	ext{ J}$$

Question 6

A sample of pudding is described as a 'heterogeneous mixture.' Which property justifies this classification?

Accepted Answer

Its components can be seen and separated physically.

Question 7

Which of the following is NOT a chemical process?

Accepted Answer

Dissolving sugar in water

Question 8

A student is given a sample of ink and is asked to determine if it is a pure substance or a mixture. Which method would best help the student make this determination?

Accepted Answer

Observing if it can be separated by physical means

Question 9

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

Accepted Answer

A compound is formed by chemical combination of elements, while a mixture is formed by physical combination of substances.

Question 10

Which of the following is a real-life example of a homogeneous mixture?

Accepted Answer

Salt dissolved in water

Question 11

A chemist needs to separate a mixture of sand and salt. Which sequence of steps would be most effective?

Accepted Answer

Add water, filter to remove sand, then evaporate water to recover salt.

Question 12

Which of the following is a chemical property?

Accepted Answer

Reactivity with acid

Question 13

A 2500 J sample of energy is equivalent to how many kilocalories?

Accepted Answer

$$0.597 	ext{ kcal}$$

Question 14

Which of the following best describes the process of distillation?

Accepted Answer

Separating substances based on differences in boiling points

Question 15

Which of the following is a physical change?

Accepted Answer

Melting ice

Question 16

A student claims that gold is a mixture because it can be found with other metals in nature. What is the flaw in this reasoning?

Accepted Answer

Gold is an element and, in its pure form, is not a mixture.

Question 17

Which of the following best explains why air is considered a mixture?

Accepted Answer

It is composed of several gases that retain their individual properties.

Question 18

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

Accepted Answer

Burning magnesium ribbon

Question 19

A student observes that a sample of ink spreads into different colors on filter paper. What does this observation indicate about the ink?

Accepted Answer

It is a mixture.

Question 20

Which of the following best describes the difference between physical and chemical changes?

Accepted Answer

Physical changes do not alter the chemical composition of a substance, while chemical changes do.

Fundamental Concepts in General Chemistry: Mixtures, Substances, and Energy

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