What is the number of moles present in 24.0 mL of 0.500M solution of sodium chloride, NaCl?
How many moles are there in 456 g of calcium fluoride, CaF2?
12?
It's pretty late to answer that question. It's been 11 years
To find the number of moles in a solution or a substance, we can use the formula:
moles = (concentration in M) x (volume in liters)
1. For the first question, you are given a 0.500 M solution of sodium chloride (NaCl) with a volume of 24.0 mL.
First, we need to convert the volume from milliliters to liters:
Volume = 24.0 mL = 24.0 / 1000 L = 0.024 L
Now, we can use the formula to calculate the number of moles:
moles = 0.500 M x 0.024 L
moles = 0.012 moles
Therefore, there are 0.012 moles of sodium chloride (NaCl) in 24.0 mL of the 0.500 M solution.
2. For the second question, you are given 456 g of calcium fluoride (CaF2).
To find the number of moles, we need to know the molar mass of calcium fluoride (CaF2). The molar mass of CaF2 can be calculated as follows:
Atomic mass of calcium (Ca) = 40.08 g/mol
Atomic mass of fluorine (F) = 18.99 g/mol
Molar mass of CaF2 = 40.08 g/mol (for Ca) + 2 x 18.99 g/mol (for 2 F atoms)
Molar mass of CaF2 = 40.08 g/mol + 2 x 18.99 g/mol
Molar mass of CaF2 = 78.08 g/mol
Now, we can use the formula to calculate the number of moles:
moles = mass / molar mass
moles = 456 g / 78.08 g/mol
moles ≈ 5.84 moles
Therefore, there are approximately 5.84 moles of calcium fluoride (CaF2) in 456 g.
To find the number of moles present, we can use the formula:
moles = concentration (in moles per liter) x volume (in liters)
For the first question, we are given the volume (24.0 mL) and the concentration (0.500M) of the sodium chloride solution. However, we need to convert the volume to liters before we can use the formula.
To convert milliliters to liters, divide the volume by 1000 since there are 1000 milliliters in a liter:
volume in liters = 24.0 mL / 1000 = 0.024 L
Now, we can use the formula:
moles = 0.500M x 0.024 L = 0.012 moles
Therefore, there are 0.012 moles of NaCl in 24.0 mL of a 0.500M sodium chloride solution.
For the second question, we are given the mass (456 g) of calcium fluoride (CaF2). To find the number of moles, we need to use the molar mass of CaF2.
The molar mass of calcium (Ca) is approximately 40.08 g/mol, and the molar mass of fluorine (F) is approximately 18.99 g/mol. Since there are two fluorine atoms in CaF2, we multiply the molar mass of fluorine by 2:
Molar mass of CaF2 = (1 x molar mass of calcium) + (2 x molar mass of fluorine)
= (1 x 40.08 g/mol) + (2 x 18.99 g/mol)
= 40.08 g/mol + 37.98 g/mol
= 78.06 g/mol
Now, we can use the formula:
moles = mass (in grams) / molar mass
moles = 456 g / 78.06 g/mol ≈ 5.85 moles
Therefore, there are approximately 5.85 moles of CaF2 in 456 g of calcium fluoride.