Do the following calculation and write the answer in proper number of significant figures 45.56 – 40.34

Identify the name of the following molecule Na2S

Identify the name of the following molecule CO2

In the paper chromatography experiment, you marked the line on chromatography paper with a pencil, the reason for this is.

Which of the following number has 4 significant figures?

Identify the name of the following molecule FeCl2

Identify the name of the following molecule Fe2O3

A student measured a a volume of liquid as 76.82 mL, and later found out it was 75.82 mL. Calculate the percent error

Identify thenumber of significant figures in thefollowing number 65200.080

When an unknown solid was added into a volumetric cylinder with 25.00 mL of water, the new volume came to 55.00 mL.  If the mass of the solid is 81.00 g, find the density of the unknown material.