COLEGIO BRITÁNICO INTERNACIONAL

SCIENCE

DENSITY EXERCISES

INFORMATION REQUIRED FOR HOMEWORK:

Table 1.- Densities of Common Substances

Substance Density (g/cm3) Substance Density (g/cm3)

Helium (gas) 0.0001663 Zinc (solid) 7.13

Oxygen (gas) 0.001331 Silver (solid) 10.50

Water (liquid) 1.00 Lead (solid) 11.35

Pyrite (solid) 5.02 Mercury (liquid) 13.55

Gold (solid) 19.32 Iron (solid) 7.9

Tin (solid) 7.3

How to convert Mass into Weight:

1 N = 100 g

EXAMPLE:

A student has a mass of 45,000 g. how much does this student weigh in Newtons?

STEP 1: Write the information given to you.

45,000 g

STEP 2: Write the conversion factor to change grams into newtons.

1 N = 100 g

STEP 3: Write the equation so that grams will cancel.

45,000 g x 1N100g

= 450 N

How to calculate Volume:

V=Length xWidth x Height

How to calculate Density:

D=MV

D= Density

M= Mass

V= Volume

EXAMPLE:

What is the density of an object whose mass is 25 g and whose volume is 10 cm3?

STEP 1: Write the equation for density.

D=MV

STEP 2: Replace m and V with the measurements given in the problem, and solve.

D=MV

= 25g10cm3

= 2.5 gcm 3

EXERCISES:

1. Suppose you have a lead ball whose mass is 454 g. What is the ball´s volume?

2. What is the mass of 15 mL sample of mercury?

3. What is the density of an object that has a mass of 350 g and a volume of 95 cm3? Would this object float in water? Explain.

4. The density of an object is 5 g/cm3, and the volume of the object is 10 cm3. What is the mass of the object?

5. What is the volume of a book that has a width of 10 cm, a length that is 2 times the width, and a height that is half the width? Remember to express your answers in cubic units.

6. A jar contains 30 mL of glycerin (whose mass is 37.8 g) and 60 mL of corn syrup (whose mass is 82.8 g). Which liquid is on top= Show your work and explain your answer.

7. Which substance has the lowest density?a. Heliumb. Pyritec. Mercuryd. Gold

8. Imagine that you had discovered a new element, and you want to find its density. It has a mass of 78.8g and a volume of 8 cm3. To find the density of the element, you must divide the element`s mass by its volume. What is the density of the element? Show your work.

a. 0.102 g/cm3

b. 0.98 g/cm3

c. 9.85 g/cm3

d. 630.4 g/cm3

9. Many soft drinks come in bottles that contain about 590 mL. If the density of a soft drink is about 1.05 g/mL, what is the mass of the drink? Show your work.

a. 0.0018 gb. 498.2 gc. 561.9 gd. 619.5 g

10. If you have 150 g of pure gold and the density of gold is 19.32 g/cm3, what is the volume of your gold nugget?

a. 2,898 cm3

b. 7.76 cm3

c. 0.98 cm3

d. 0.13 cm3

11. Three objects have a mass of 16 g each. But their volumes differ. Object A, a liquid, has a volume of 1.2 mL. Object B, a solid, has a volume of 3.2 cm3. Object C, another solid, has a volume of 1,9 cm3. Which object is the least dense? Show your work.

12. A small block of wood floats on water. It has a mass of 200g and a volume of 250 cm3. What is the density of the wood?

13. A sample of liquid has a mass of 24 g and a volume of 16 mL. What is the density of the liquid?

14. A piece of solid metal has a mass of 43.5 g and a volume of 15 cm3. What is the density of the metal?

15. A piece of metal has a volume of 38 cm3 and a mass of 277 g. Calculate the density of the metal, and identify it based on table 1.

16. A plastic box is 15.3 cm long, 9.0 cm wide and 4.5 cm high. What is its volume? It´s mass is 102 g. What is its density? Include units in your answers.

17. The density of sulfur is 2.0 g/cm3. What is the mass of a sample of sulfur that has a volume of 6.0 cm3?

a. 3.0 gb. 8.0 gc. 4.0 gd. 12 g

18. A piece of magnesium metal has a mass of 56.5 g and a volume of 32.5 cm3. What is the density of the magnesium?

19. You have participated in an athletic competition and won a gold medal and your best friend a silver medal. Both of medals have a volume of 3.5 cm3. Calculate the mass of each medal and the weight of each one of them. Include units in your answers.

20. What is the weight of a car that has a mass of 1,362,000 g?