Question

How many molecules are present in 0. 340 g of HCl?

Answer 1

Answer:

N (molecules) = 5.60 x 10^21 molecules

Step-by-step explanation:

To calculate the number of molecules in a given mass of a substance, we need to use the following steps:

Calculate the number of moles of the substance using its molar mass.
Use Avogadro's number to convert the number of moles to the number of molecules.
The molar mass of HCl is the sum of the molar masses of hydrogen (1.008 g/mol) and chlorine (35.45 g/mol), which gives:

Molar mass of HCl = 1.008 g/mol + 35.45 g/mol = 36.458 g/mol

Using the given mass of HCl, we can now calculate the number of moles:

moles of HCl = mass of HCl / molar mass of HCl
moles of HCl = 0.340 g / 36.458 g/mol
moles of HCl = 0.00933 mol

Finally, we can convert the number of moles to the number of molecules using Avogadro's number:

number of molecules = moles of HCl x Avogadro's number
number of molecules = 0.00933 mol x 6.022 x 10^23 molecules/mol
number of molecules = 5.60 x 10^21 molecules

Therefore, there are approximately 5.60 x 10^21 molecules in 0.340 g of HCl.

Answer 2

To determine the number of molecules present in a sample of HCl, we need to use the Avogadro's constant and the molecular weight of HCl.

The molecular weight of HCl is approximately 36.46 g/mol (1.01 g/mol for hydrogen plus 35.45 g/mol for chlorine).

Using this information, we can calculate the number of moles of HCl in 0.340 g as follows:

moles of HCl = mass of HCl / molecular weight of HCl
moles of HCl = 0.340 g / 36.46 g/mol
moles of HCl = 0.00933 mol

Next, we can use Avogadro's constant, which is approximately 6.022 x 10^23 molecules/mol, to calculate the number of molecules of HCl in 0.340 g:

number of molecules of HCl = moles of HCl x Avogadro's constant
number of molecules of HCl = 0.00933 mol x 6.022 x 10^23 molecules/mol
number of molecules of HCl = 5.61 x 10^21 molecules

Therefore, there are approximately 5.61 x 10^21 molecules of HCl present in 0.340 g of HCl.