How many HNO3 molecules are in 4.20 grams?

4.01x 10 ²² molecules HNO3

Explanation: Solution attached:

Convert mass of HNO3 to moles using its molar mass.

Convert moles of HNO3 to molecules using the Avogadro's number

4.20 g HNO3 x 1 mole HNO3 / 63 g HNO3 x 6.022x10²³ molecules HNO3 / 1 mole HNO3

= 4.0X 10 ²² molecules HNO3

a 20-cm-long, cylindrical graphite (pure carbon) rod is inserted into an oxidizing atmosphere at 1145 k and 1.013 x 105 pa pressure. the oxidizing process is limited by the diffu- sion of oxygen counterflow to the carbon monoxide that is formed on the cylindrical surface.

so she was walking and she stepped on warm jeffy , uh uh uhh dadye i just pooped my pants