Final answer:
To convert from molecules to grams, we use the equation grams = number of molecules * molar mass. Therefore, the number of grams in 6.78*10^19 molecules of NaCl would be 3.96*10^21 grams. To determine the number of molecules in 234 grams of water, we use the equation moles = grams / molar mass and then multiply by Avogadro's number.
Step-by-step explanation:
To determine the number of grams in 6.78*10^19 molecules of sodium chloride, we need to calculate the molar mass of NaCl. Sodium (Na) has a molar mass of 23.0 g/mol, and chlorine (Cl) has a molar mass of 35.5 g/mol. Adding these together, we get a molar mass of 58.5 g/mol for NaCl.
To convert from molecules to grams, we use the following equation:
grams = number of molecules * molar mass
Therefore, the number of grams in 6.78*10^19 molecules of NaCl would be:
grams = (6.78*10^19) * (58.5 g/mol) = 3.96*10^21 g
To determine the number of molecules in 234 grams of water, we need to calculate the number of moles first. The molar mass of water (H2O) is 18.0 g/mol. We can use the equation:
moles = grams / molar mass
moles = 234 g / 18.0 g/mol = 13 moles
One mole of a substance contains Avogadro's number (6.02*10^23) of molecules. So, for 13 moles of water, the number of molecules would be:
molecules = moles * Avogadro's number
molecules = 13 moles * (6.02*10^23) = 7.83*10^24 molecules