Q: A sample of water is heated from $$20\ ^\circ\mathrm{C} to$$ $$80\ ^\circ\mathrm{C}. If $$the mass of water is $$50\ \mathrm{g}$$ and the specific heat capacity is $$4.18\ \mathrm{J}/\mathrm{g}^\circ\mathrm{C}$$, how much heat is absorbed?

$$q = 50 \times 4.18 \times (80-20) = 12,540\ \mathrm{J}$$

Question 1

Which of the following best describes a compound?

Accepted Answer

A substance composed of two or more elements chemically combined in a fixed ratio.

Question 2

Which process would best separate a mixture of sand and salt water?

Accepted Answer

Filtration followed by evaporation.

Question 3

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

Accepted Answer

Iron rusts when exposed to oxygen.

Question 4

A student heats a sample of ice at $$-10\ ^\circ\mathrm{C}$$ until it becomes steam at $$110\ ^\circ\mathrm{C}. $$Which of the following describes all the physical changes that occur?

Accepted Answer

Melting and boiling.

Question 5

Which of the following equations correctly relates heat, mass, specific heat, and temperature change?

Accepted Answer

$$q = m c \Delta T$$

Question 6

A reaction in a beaker causes the temperature of the surroundings to decrease. Which term best describes this reaction?

Accepted Answer

Endothermic

Question 7

Which of the following is NOT a physical property?

Accepted Answer

Flammability

Question 8

Convert $$25\ ^\circ\mathrm{C} to $$Kelvin.

Accepted Answer

$$298\ \mathrm{K}$$

Question 9

Which statement best describes the Law of Conservation of Mass?

Accepted Answer

The total mass of reactants equals the total mass of products in a chemical reaction.

Question 10

Which of the following is a heterogeneous mixture?

Accepted Answer

Salad dressing with oil and vinegar.

Question 11

A sample of water is heated from $$20\ ^\circ\mathrm{C} to$$ $$80\ ^\circ\mathrm{C}. If $$the mass of water is $$50\ \mathrm{g}$$ and the specific heat capacity is $$4.18\ \mathrm{J}/\mathrm{g}^\circ\mathrm{C}$$, how much heat is absorbed?

Accepted Answer

$$q = 50 	imes 4.18 	imes (80-20) = 12,540\ \mathrm{J}$$

Question 12

Which of the following is an example of an exothermic process?

Accepted Answer

Combustion of gasoline in a car engine.

Question 13

Which of the following best describes potential energy?

Accepted Answer

Energy stored due to position or composition.

Question 14

Which technique would best separate the components of ink in a marker?

Accepted Answer

Chromatography

Question 15

Which of the following is a pure substance?

Accepted Answer

Oxygen gas ($$\mathrm{O}_2)$$

Question 16

A chemical formula provides information about:

Accepted Answer

The elements present and their ratios in a compound.

Question 17

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

Accepted Answer

Boiling water to produce steam.

Question 18

Convert $$100\ ^\circ\mathrm{F} to $$Celsius using the formula $$C = \frac{5}{9}(F-32). $$What is the result?

Accepted Answer

$$37.8\ ^\circ\mathrm{C}$$

Question 19

Which of the following best describes a homogeneous mixture?

Accepted Answer

A mixture with uniform composition throughout.

Question 20

Which of the following statements about energy is correct?

Accepted Answer

Energy can be converted from one form to another but cannot be created or destroyed.

3: Matter and Energy: Foundations of General Chemistry

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