Q: Convert $$\displaystyle 0.0750\ \mathrm{kg} to $$milligrams ($$\displaystyle \mathrm{mg}).$$

$$\displaystyle 7.50 \times 10$$^{5}$$\ \mathrm{mg}$$

Q: Which of the following is the correct scientific notation for the number $$\displaystyle 0.000560$$?

$$\displaystyle 5.60 \times 10$$^{-4}$$

Question 1

Which of the following statements best describes the difference between a physical and a chemical change? Consider the example of boiling water and burning wood.

Accepted Answer

Boiling water is a physical change because the composition of water remains the same, while burning wood is a chemical change because new substances are produced.

Question 2

A student measures the mass of a sample as 12.30 g and its volume as 4.1 mL. What is the density of the sample, reported with the correct number of significant figures?

Accepted Answer

$$\displaystyle 3.0\ \mathrm{g/mL}$$

Question 3

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

Accepted Answer

Salt dissolved in water

Question 4

Convert $$\displaystyle 0.0750\ \mathrm{kg} to $$milligrams ($$\displaystyle \mathrm{mg}).$$

Accepted Answer

$$\displaystyle 7.50 	imes 10$$^{5}$$\ \mathrm{mg}$$

Question 5

Which of the following is an exact number?

Accepted Answer

The number of students in a classroom

Question 6

A patient’s body temperature is measured as $$\displaystyle 39.2\ ^\circ\mathrm{C}. $$What is this temperature in Kelvin?

Accepted Answer

$$\displaystyle 312.4\ \mathrm{K}$$

Question 7

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

Accepted Answer

A compound consists of two or more elements chemically combined in a fixed ratio, while an element is a pure substance that cannot be broken down by chemical means.

Question 8

A nutrition label states that a snack contains $$\displaystyle 150\ \mathrm{Cal} ($$dietary calories). How much energy is this in kilojoules ($$\displaystyle \mathrm{kJ}$$)? (1 Cal $$\displaystyle = 4.184\ \mathrm{kJ})$$

Accepted Answer

$$\displaystyle 627.6\ \mathrm{kJ}$$

Question 9

Which of the following is a chemical property?

Accepted Answer

Ability to react with oxygen

Question 10

A sample of metal requires $$\displaystyle 1250\ \mathrm{J} of $$energy to raise its temperature from $$\displaystyle 20.0\ ^\circ\mathrm{C} to$$ $$\displaystyle 45.0\ ^\circ\mathrm{C}. If $$the mass of the metal is $$\displaystyle 50.0\ \mathrm{g}$$, what is its specific heat ($$\displaystyle c$$)?

Accepted Answer

$$\displaystyle 1.00\ \mathrm{J/g\ ^\circ C}$$

Question 11

Which of the following is the correct scientific notation for the number $$\displaystyle 0.000560$$?

Accepted Answer

$$\displaystyle 5.60 	imes 10$$^{-4}$$

Question 12

A student needs to prepare $$\displaystyle 250.0\ \mathrm{mL} of a $$solution. How many liters is this?

Accepted Answer

$$\displaystyle 0.2500\ \mathrm{L}$$

Question 13

Which of the following best describes a heterogeneous mixture?

Accepted Answer

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

Question 14

A block of ice at $$\displaystyle -5.0\ ^\circ\mathrm{C} is $$heated until it becomes liquid water at $$\displaystyle 25.0\ ^\circ\mathrm{C}. $$Which of the following processes occur during this transformation?

Accepted Answer

A physical change involving both a change of state and a change in temperature

Question 15

Which of the following conversion factors is correct for converting from centimeters to meters?

Accepted Answer

$$\displaystyle 1\ \mathrm{cm} = 0.01\ \mathrm{m}$$

Question 16

A sample of ethanol has a density of $$\displaystyle 0.789\ \mathrm{g/mL}. $$What is the mass of $$\displaystyle 50.0\ \mathrm{mL} of $$ethanol?

Accepted Answer

$$\displaystyle 39.5\ \mathrm{g}$$

Question 17

Which of the following statements about significant figures is correct?

Accepted Answer

All nonzero digits are significant.

Question 18

A temperature is recorded as $$\displaystyle 68.0\ ^\circ\mathrm{F}. $$What is this temperature in degrees Celsius ($$\displaystyle ^\circ\mathrm{C}$$)? (Use $$\displaystyle ^\circ\mathrm{C} = ( ^\circ\mathrm{F} - 32 ) 	imes \frac{5}{9})$$

Accepted Answer

$$\displaystyle 20.0\ ^\circ\mathrm{C}$$

Question 19

Which of the following best describes the state of matter for oxygen gas at room temperature?

Accepted Answer

Gas

Question 20

A chemist needs to convert $$\displaystyle 3.25\ \mathrm{L} of a $$solution to quarts ($$\displaystyle \mathrm{qt}). If$$ $$\displaystyle 1\ \mathrm{qt} = 0.946\ \mathrm{L}$$, how many quarts is this?

Accepted Answer

$$\displaystyle 3.44\ \mathrm{qt}$$

Matter, Energy, and Measurement in General Chemistry

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