Q: A laboratory sample has a mass of $$0.451\ \mathrm{kg}. $$Convert this mass to milligrams ($$\mathrm{mg}) $$using the appropriate metric prefix.

$$4.51 \times 10^5$\ \mathrm{mg}$$

Q: Which of the following is the correct calculation for the atomic mass of chlorine if it consists of $$75.77\%$$ chlorine-35 (mass $$34.97\ \mathrm{amu}) $$and $$24.23\%$$ chlorine-37 (mass $$36.97\ \mathrm{amu}$$)?

$$0.7577 \times 34.97 + 0.2423 \times 36.97$$

Question 1

Which of the following is the correct SI base unit and abbreviation for measuring electric current?

Accepted Answer

Ampere (A)

Question 2

A laboratory sample has a mass of $$0.451\ \mathrm{kg}. $$Convert this mass to milligrams ($$\mathrm{mg}) $$using the appropriate metric prefix.

Accepted Answer

$$4.51 	imes 10^5$\ \mathrm{mg}$$

Question 3

Which of the following best describes the difference between accuracy and precision in scientific measurements?

Accepted Answer

Accuracy is how close measurements are to the true value; precision is how close measurements are to each other.

Question 4

A cube of gold has a length of $$2.00\ \mathrm{cm} on $$each side. Given the density of gold is $$19.32\ \mathrm{g/cm^3$}$$, what is the mass of the cube?

Accepted Answer

$$77.28\ \mathrm{g}$$

Question 5

Which of the following is a derived SI unit?

Accepted Answer

Liter (L)

Question 6

A graduated cylinder contains a liquid with a meniscus at $$4.30\ \mathrm{mL}. If $$the cylinder is marked every $$0.1\ \mathrm{mL}$$, how many significant figures should you report for the volume?

Accepted Answer

Three

Question 7

Which of the following statements about mixtures and pure substances is correct?

Accepted Answer

A homogeneous mixture has a variable composition and appears as one substance.

Question 8

Which separation technique would be most appropriate for separating a mixture of sand and water?

Accepted Answer

Filtration

Question 9

A sample of ethanol has a mass of $$15.8\ \mathrm{g}$$ and a volume of $$20.0\ \mathrm{mL}. $$What is the density of ethanol in $$\mathrm{g/mL}$$, reported to the correct number of significant figures?

Accepted Answer

$$0.790\ \mathrm{g/mL}$$

Question 10

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

Accepted Answer

Iron rusts when exposed to oxygen.

Question 11

A student adds $$23.4\ \mathrm{g}$$, $$102.45\ \mathrm{g}$$, and $$0.003\ \mathrm{g}$$ together. What is the sum, reported to the correct number of decimal places?

Accepted Answer

$$125.9\ \mathrm{g}$$

Question 12

Which law states that all samples of a given compound have the same proportions of their constituent elements?

Accepted Answer

Law of Definite Proportions

Question 13

Which experiment led to the discovery of the nucleus in the atom?

Accepted Answer

Gold foil experiment

Question 14

Which of the following statements about isotopes is correct?

Accepted Answer

Isotopes of an element have the same number of protons but different numbers of neutrons.

Question 15

A chlorine isotope has 17 protons and 18 neutrons. What is its mass number?

Accepted Answer

$$35$$

Question 16

Which of the following is the correct formula for density?

Accepted Answer

$$\mathrm{Density} = \dfrac{\mathrm{mass}}{\mathrm{volume}}$$

Question 17

Which of the following best describes a cation?

Accepted Answer

An atom that has lost electrons and is positively charged.

Question 18

A sample of water is decomposed and produces $$2.0\ \mathrm{g} of $$hydrogen and $$16.0\ \mathrm{g} of $$oxygen. What is the mass ratio of oxygen to hydrogen in water?

Accepted Answer

$$8:1$$

Question 19

Which of the following is the correct calculation for the atomic mass of chlorine if it consists of $$75.77\%$$ chlorine-35 (mass $$34.97\ \mathrm{amu}) $$and $$24.23\%$$ chlorine-37 (mass $$36.97\ \mathrm{amu}$$)?

Accepted Answer

$$0.7577 	imes 34.97 + 0.2423 	imes 36.97$$

Question 20

Which of the following is a physical change?

Accepted Answer

Melting of ice

Matter and Measurement: Foundations of General Chemistry

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