Question

A 100.00 mL volumetric flask weighs 35.9325 g. When an unknown solid is added to it, the flask and sample weigh 48.8565 g. Deionized water is added to the calibration mark. The flask, sample, and water together weigh 140.8321 g. Calculate the density of the unknown, assuming the density of water is 0.998203 g/mL.

Answer 1

1.64 g/mL

Step-by-step explanation:

Step 1: Calculate the mass of the solid

m(solid+flask) = m(solid) + m(flask)

m(solid) = m(solid+flask) - m(flask)

m(solid) = 48.8565 g - 35.9325 g = 12.9240 g

Step 2: Calculate the mass of water

m(solid+flask+water) = m(solid+flask) + m(water)

m(water) = m(solid+flask+water) - m(solid+flask)

m(water) = 140.8321 g - 48.8565 g = 91.9756 g

Step 3: Calculate the volume occupied by 91.9756 g of water

The density of water is 0.998203 g/mL.

91.9756 g × 1 mL/0.998203 g = 92.1412 mL

Step 4: Calculate the volume occupied by the solid

The 100.00 mL are occupied by the solid and the water.

100.00 mL = V(solid) + V(water

V(solid) = 100.00 mL - V(water)

V(solid) = 100.00 mL - 92.1412 mL = 7.86 mL

Step 5: Calculate the density of the solid

12.9240 g of the solid occupy 7.86 mL.

ρ = 12.9240 g/7.86 mL = 1.64 g/mL