Question

A graduated cylinder is filled with 20ml of water. A rock is dropped in to the graduated cyclinder and the volume of water rises to 30ml
inside the graduated cylinder. The mass of the rock is 23g. What is the density of the rock?
2.3g/ml
0.77g/ml
5g/ml
1.15g/ml

Answer 1

Answer:

$\boxed {\boxed {\sf 2.3 \ g/mL}}$

Explanation:

We are asked to find the density of a rock. Density is the substance's mass per unit volume. The formula for calculating density is:

$\rho= \frac{m}{v}$

The mass of the rock is 23 grams. The volume was found using water displacement. A known amount of water was measured, the rock was added to the graduated cylinder, and the water level was recorded again. The volume is the difference between the final and initial water level. The graduated cylinder originally had 20 milliliters and the water rose to 30 milliliters.

• volume = final water level - initial water level
• volume = 30 mL - 20 mL
• volume = 10 mL

Now we know the mass and the volume.

• m= 23 g
• v= 10 mL

Substitute the values into the formula.

$\rho= \frac{ 23 \ g }{30 \ mL}$

Divide.

$\rho= 2.3 \ g/mL$

The density of the rock is 2.3 grams per milliliter.