1. Lesson 3 I’m having a meltdown
What are the benefits of snow? Be prepared to discuss 3
Calculate the density of a material with a mass of 25.0g and a volume of 7.0mL

2. Work with your lab partner…

3. Discussion

4. Worksheet Answers:
What is the volume of 12 g of snow? How do you know? What is the volume of 12 g of ice?
24mL. From graph. 14mL
Place 12 g of rain, 12 g of snow, and 12 g of ice in order of increasing volume. Use density to explain the order.
Rain<ice<snow
Examine the lines on the graph for rain, snow, and ice. How is the steepness of each line related to the density of each substance?
More steep = greater density.

5. Worksheet Answers cont…
Imagine a 24 mL sample of snow from the mountains. When the snow melts, what is the volume of liquid water? Assume that the snow has density 0.5 g/mL. Using the graph… 24mL snow = 12g snow. 12g snow = 12 g water. 12g water = 12mL water. Using proportions 𝑣𝑜𝑙𝑢𝑚𝑒 𝑠𝑛𝑜𝑤 𝑑𝑒𝑛𝑖𝑠𝑡𝑦 𝑠𝑛𝑜𝑤 = 𝑣𝑜𝑙𝑢𝑚𝑒 𝑤𝑎𝑡𝑒𝑟 𝑑𝑒𝑛𝑖𝑠𝑡𝑦 𝑤𝑎𝑡𝑒𝑟 = 𝑋 1 24mL snow = 12mL water

6. Wrap up:
Density = 𝑀𝑎𝑠𝑠 𝑉𝑜𝑙𝑢𝑚𝑒
In density calculations, mass and volume are proportional to each other.
Phase changes (solid  liquid  gas) result in density changes.
Density: snow < ice < water

7. HW:
Page 268 # 3-9

8. HW answers
3 – densities are different, intermolecular forces affect geometry
4 – less.
5 – (use proportions) mass = Vol * Density so: (V*D)ice = (V*D)water
(24)(0.92) = (x)(1)
6 – 0.5 g/mL (multiple ways to figure this out…)
7a- V=17.5mL, D=0.92g/mL, M=?
b- V=17.5mL, D=1.0 g/mL, M=?