Significant Figures
Which of the following numbers has exactly 3 significant figures?
A) 0.0056 B) 0.056 C) 56.0 D) 560
C) 56.0
A block of metal has a mass of 20 g and a volume of 4.0 cm³. What is its density?
5.0 g/cm³
When ice melts into liquid water, what phase change is occurring?
Melting/Fusion
What is the formula for the Combined Gas Law?
P1V1/T1 = P2V2/T2
What subatomic particle determines an atom’s identity (the element it is)?
The number of protons
How many significant figures are in the number 0.004530?
4 significant figures
A sample of clay has a density of 2.5 g/cm³ and a volume of 10.0 cm³. What is its mass?
25 g
When liquid water changes into water vapor, what is this phase change called?
Evaporation/Boiling
A gas has a volume of 2.0 L at 1.0 atm and 300 K.
If the pressure increases to 2.0 atm and temperature stays the same, what is the new volume?
1.0 L
How many protons, neutrons, and electrons are in a neutral atom of chlorine-37?
Protons = 17, Electrons = 17, Neutrons = 37 − 17 = 20
12.45 + 3.6 = ?
16.1
A mineral has a mass of 48 g and a density of 6.0 g/cm³. What is its volume?
8.0 cm³
When water vapor turns back into liquid water, what is this phase change?
Condensation
A 5.0 L sample of gas at 1.0 atm and 273 K is heated to 546 K while the pressure is held constant. What is the new volume?
10.0 L
How many electrons are in a Fe³⁺ (iron(III)) ion?
23 electrons
4.56 x 1.4 = ?
6.4
A piece of wood has a mass of 36.0 g and displaces 45.0 cm³ of water. What is its density?
0.80 g/cm³
When frost forms directly from water vapor on a cold morning without becoming liquid first, what phase change has occurred?
Deposition
A gas at 1.2 atm and 250 K occupies 3.0 L. If the temperature increases to 500 K and pressure increases to 2.4 atm, what is the new volume?
3.0 L
A neutral atom of magnesium-25 has 12 protons. How many neutrons and electrons does it have?
Neutrons = 25 − 12 = 13, Electrons = 12
(12.11 + 18.0 + 1.013) ÷ 3.00 = ?
10.4
A cube of an unknown metal has edges measuring 2.0 cm on each side and a mass of 63.0 g.
Which of the following metals is it most likely to be?
Aluminum (2.7 g/cm³), Iron (7.9 g/cm³), Copper (8.9 g/cm³), Lead (11.3 g/cm³)
Iron
When dry ice (solid CO₂) disappears into gas without forming a liquid, what is that phase change called?
Sublimation
A 400 mL gas sample at 760 mmHg and 300 K is cooled to 150 K and the pressure drops to 380 mmHg. What is the new volume?
400 mL
An element has two naturally occurring isotopes: X-10 with an abundance of 20.0%, X-11 with an abundance of 80.0%. What is the average atomic mass of the element?
(10.0)(0.200)+(11.0)(0.800)=10.8 amu