Question

an aqueous solution solution of sodium borate is sometimes used to to fire-proof wood.
a. what is the molarity of 2.50 L of solution that contains 1.85 moles of sodium borate?

b. what is the molarity of 45.0 L of solution that contains 6.78 kg of sodium borate?

c. how manny moles of sodium borate are in 600.0 mL of a 1.57 M sodium borate solution?

d. a chemist needs 50.8 g of sodium borste for a reaction. How many mL of 1.87 M solution contain this mass?

Answer 1

An aqueous solution solution of sodium borate is sometimes used to to fire-proof wood.
a. what is the molarity of 2.50 L of solution that contains 1.85 moles of sodium borate?
<b>M = mols/L</b>

b. what is the molarity of 45.0 L of solution that contains 6.78 kg of sodium borate?
<b>Convert kg to grams, then
mols sodium borate = grams/molar mass.
Then M = mols/L</b>

c. how many moles of sodium borate are in 600.0 mL of a 1.57 M sodium borate solution?
<b>mols = M x L</b>

d. a chemist needs 50.8 g of sodium borste for a reaction. How many mL of 1.87 M solution contain this mass?
<b> How many mols do you need? That's mols = grams/molar mass. solve for mols. Then
M = mols/L; rearrange to L = mols/M. You have mol and M, solve for L and convert to mL.</b>