Unit 1: Matter (Mass, Volume, Density) Vocabulary and Practice Questions
Precipitate
A solid that forms from a solution during a chemical reaction.
Slope (in terms of mass vs. volume)
The density or mass per unit volume. The x-axis is volume and the y-axis is mass.
Density
The ratio of the mass of a substance to the volume of the substance; mass/ volume.
How can density be used to identify unknown substances?
All substances have their own density therefore the substances can be compared to other substances to determine what each substance is.
What is the density of water?
Answer: 1 g/mL or 1g/ cm^3 (Note: mL = cm^3)
Practice Question #3: Object B has a density of 12.5 g/cm^3 and a mass of 17g. What is the volume of object B?
Answer: 1.36 cm^3
Practice Question #2: Object A has a mass of 22g and a volume of 16 mL. what is the density of object A?
Answer: 1.375 g/mL
Practice Question #4: Ethanol has a density of 0.789 g/cm^3. What is the mass of 173 cm^3 of ethanol?
Answer: 136.497g
Practice Question #8: A cube of lead measures 6cm on each side. Lead has a density of 11.35 g/mL. What is the volume of the cube? What is the mass?
Answer: 216 cm^3; 2,451.6g
Practice Question #9: A cube of copper measures 3cm on each side. Copper has a density of 8.96 g/mL. What is the volume of the cube? What is the mass?
Answer: 27cm^3; 241.92g
Practice Question #1: A student filled a graduated cylinder with water and read the meniscus at 56.7 mL. The student then dropped a solid material into the graduated cylinder and the water rose to 62.5 mL. If the solid had a density of 5.22 g/mL, determine the mass of the solid object.
Answer: 30.276 g
Practice Question #7: A cube of titanium measures 2cm on each side. Titanium has a density of 4.54 g/mL. What is the volume of the cube? What is the mass?
Answer: 8cm^3; 36.32g
Practice Question #5: The density of olive oil is 0.911 g/cm^3. What would happen to a cup of olive oil when poured into a glass of water?
Answer: It would float.
Practice Question #6: The density of mercury is 13.55 g/mL. What would happen to an ounce of mercury when poured into a cup of water?
Answer: It would sink.
Practice Question #10 (Bonus?): A jeweler needs 20g of sliver wire to make custom necklaces for you and your 3 best friends. But the jeweler didn't pass math in high school and doesn't know the size or length of wire he needs. The density of silver is 10.50 g/mL. a) What is the volume of the silver wire? b) If every 2.0cm length of silver wire has a mass of 0.15g, how long would the 20g of wire be? c) What is the diameter of the sliver wire? (assume it's a cylinder) d) How long would each necklace be in inches? (there are 4 people) 1 inch = 2.54 cm
Answer: a) 1.9 mL b) 266.7 cm c) 0.095cm or 0.1cm d) 26.25 inches
Tare
Changing the zero on an electronic balance, the weight of an empty container.
Note for test!
Make sure to study particle diagrams and histograms. Know how to draw particle diagrams for various densities and solid, liquid, gas states. Know how to plot data on a histogram and be able to read the graph (ie. its level of precision, etc).
Law of Conservation of Mass
Mass will not change in a closed system, meaning nothing is being added into or taken away from the system.
Mass
The amount of matter in an object.
Area of uncertainty
The range of possible values that contains the exact answer, raises the rate of precision.
Volume
The amount of space an object takes up.
Meniscus
The curve at a liquid's surface by which one measures the volume of the liquid.
