Here are some of the questions I got assigned today I was away for the lesson:

Density:

Calculate the density of a 2.0 L object which has a mass of 4.0 kg

What is the mass of 100.0 ml of lead? (It has a density of 11.35 g/ml)

What is the volume of 13.0 g of gold? (It has a density of 19.2 g/ml)

What is the mass of 100.0 ml of sulphuric acid? (It has a density of 1.85 g/ml)

What volume will 3.00 x 102 g of mercury occupy? (It has a density of 13.55 g/ml)

What is the density of a gas, which has a mass of 2.50 g and occupies 1.50 ml?

What is the density of a solution of HCl, which has a mass of 17.84 g and a volume of 15.00 ml?

What is the density of a solid piece of iron, which has a mass of 11.78 g and is 3.00 cm ling, 1.00 cm wide and 0.50 cm thick?

A sample of copper has a density of 8.92 g/ml and measures 4.00 cm long, 2.00 cm wide and 1.00 cm thick. What is the mass in grams of this block of copper?

Several irregular shaped pieces of zinc are dropped into a graduated cylinder containing 18.0 ml of water. The water level rises to 22.2 ml. What is the density of the zinc if it weighs 30.0 g?

What is the volume in litres occupied by 50.0 kg of ethanol at 200C? The density of ethanol at this temperature is 0.789 g/ml

Can someone give me the answer to a few and how they got those answers?

## Answers (1)

density = mass / volume

volume = mass / density

mass = density * volume

I'll solve 9 and 10 cause they are a bit harder.

9.

V = a*b*c = 4*2*1 = 8 cm^3

1 ml = 1 cm^3 so 8.92 g/ml = 8.92 g/cm^3

So V = 8 cm3 and density = 8.92. If mass = v*d, then

8*8.92 = 71.36 grams.

10.

V of water after you put the zinc increased by 22.2 cm^3, so that is the volume of zinc.

Its density is 30 g / 22.2 cm^3 = 1.35 g/cm^3. This is not true, though. Density of zinc is far bigger than this. Are you sure you didn't type it wrong? If you didn't then it's just a random theoretical question.