To calculate the number of molecules in a given sample of a compound, Shirley needs to use the following values in her calculation:
1. The amount of the compound in grams: This value is provided in the question and represents the mass of the compound.
2. Avogadro's number: This is a constant value that represents the number of molecules in one mole of a substance. It is approximately 6.022 × 10^23 molecules per mole.
3. The molar mass of the compound: This value represents the mass of one mole of the compound. It is usually given in grams per mole and can be found in the periodic table.
4. The density of the compound: This value represents the mass of the compound per unit volume. It is usually given in grams per cubic centimeter (g/cm^3) or grams per milliliter (g/mL).
To calculate the number of molecules, Shirley can use the following steps:
1. Convert the mass of the compound to moles by dividing the mass by the molar mass. This gives the number of moles of the compound.
2. Multiply the number of moles by Avogadro's number to calculate the number of molecules. This gives the MAINANSWER.
EXPLAYNATION:
By using these values, Shirley can accurately calculate the number of molecules in the given sample of her compound. The molar mass is used to convert the mass of the compound to moles, and then multiplying by Avogadro's number gives the number of molecules.
For example, let's say Shirley has 10 grams of a compound with a molar mass of 20 g/mol. She can calculate the number of moles by dividing 10 grams by 20 g/mol, which gives 0.5 moles. Then, multiplying by Avogadro's number (6.022 × 10^23 molecules/mol), she finds that there are 3.011 × 10^23 molecules in her sample.
In summary, Shirley needs to use the mass of the compound, Avogadro's number, the molar mass of the compound, and the density of the compound to calculate the number of molecules in a given sample. By following the steps mentioned above, she can accurately determine the number of molecules.