Q: Which of the following is the correct equation for calculating the atomic mass of an element with two isotopes?

$\text{Atomic mass} = (\text{fraction of isotope 1}) \times (\text{mass of isotope 1}) + (\text{fraction of isotope 2}) \times (\text{mass of isotope 2})$

Question 1

Which of the following statements best explains why graphite and diamond, both made of carbon, have such different properties?

Accepted Answer

The atoms in graphite are arranged in sheets, while in diamond they are arranged in a three-dimensional structure.

Question 2

Which of the following is a chemical property of gasoline?

Accepted Answer

Its flammability

Question 3

A sample of water is heated from $25\ ^\circ\mathrm{C}$ to $100\ ^\circ\mathrm{C}$ and boils. Which of the following best describes the change?

Accepted Answer

A physical change, because the water molecules remain the same.

Question 4

Which separation technique would be most appropriate to separate a mixture of sand and water?

Accepted Answer

Filtration

Question 5

Which of the following is an example of an intensive property?

Accepted Answer

Density

Question 6

A student measures the mass of a lead block four times and gets values close to each other but far from the true value. What does this indicate?

Accepted Answer

The measurements are precise but not accurate.

Question 7

Which of the following best describes the law of definite proportions?

Accepted Answer

All samples of a given compound have the same proportions of their constituent elements.

Question 8

A sample of ammonia contains 10.0 g of hydrogen. If the mass ratio of nitrogen to hydrogen in ammonia is $4.7:1$, how many grams of nitrogen does it contain?

Accepted Answer

$47\ \mathrm{g}$

Question 9

Which experiment provided evidence for the existence of the nucleus in the atom?

Accepted Answer

Rutherford’s gold foil experiment

Question 10

How many electrons are present in the $\mathrm{O}^{2-}$ ion?

Accepted Answer

$10$

Question 11

Which of the following is the correct formula for converting Celsius to Kelvin?

Accepted Answer

$K = ^\circ C + 273.15$

Question 12

Which prefix multiplier is most appropriate for reporting a measurement of $5.57 	imes 10^{-5}\ \mathrm{m}$?

Accepted Answer

milli

Question 13

A sample contains $3.01 	imes 10^{23}$ atoms of carbon. How many moles of carbon are present?

Accepted Answer

$0.500$ mol

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

Which element contains 50 protons in its nucleus?

Accepted Answer

Tin

Question 16

Which of the following best describes a heterogeneous mixture?

Accepted Answer

A mixture in which the composition varies from one region to another.

Question 17

Which type of energy is chemical energy?

Accepted Answer

Potential energy

Question 18

Which group of elements is known for being mostly unreactive?

Accepted Answer

Noble gases

Question 19

A sample of copper is heated from room temperature to $95\ ^\circ\mathrm{C}$. What happens to its density?

Accepted Answer

The sample expands and its density decreases.

Question 20

Which of the following is the correct equation for calculating the atomic mass of an element with two isotopes?

Accepted Answer

$	ext{Atomic mass} = (	ext{fraction of isotope 1}) 	imes (	ext{mass of isotope 1}) + (	ext{fraction of isotope 2}) 	imes (	ext{mass of isotope 2})$

Chapter 1 & 2 Study Notes: Matter, Measurement, Problem Solving, Atoms & Elements

Study Guide - Practice Questions

Study Guide - Flashcards