Round your answer to the correct number of significant digits and show work.
1. How many grams of NaI would be used to produce a 2.0 M solution with a volume of 10.00 L?
2. What is the molarity of a 2.50 x 102 cm3 solution containing 450.0 g of C6H12O6 ?
3. How many moles of Sr(NO3)2 would be used in the preparation of 20.50 L of a 30.5 M solution
For #1 I think-
20/10.00
149.89X20=2997.8 (not sure)
molarity=mass/(molmass*volumeinLiters)
a. mass=molarity*molemass*volumeinLiters
b. see definition above on Molarity
c.moles= molarity*volumeinliters
To solve these problems, we need to use the equations that relate molarity, volume, and the number of moles of a substance.
1. To find the number of grams of NaI needed to make a 2.0 M solution with a volume of 10.00 L, we need to find the number of moles of NaI required first. The equation we can use is:
Molarity (M) = Moles (mol) / Volume (L)
Rearranging the equation, we have:
Moles (mol) = Molarity (M) x Volume (L)
Substituting the given values, we have:
Moles (mol) = 2.0 M x 10.00 L = 20.0 mol
To find the mass in grams, we need to use the molar mass of NaI, which is Na (22.99 g/mol) + I (126.90 g/mol) = 149.89 g/mol. Now, we can calculate the grams of NaI:
Grams = Moles (mol) x Molar Mass (g/mol) = 20.0 mol x 149.89 g/mol = 2997.8 g
Rounding the answer to the correct number of significant digits, we get:
Grams of NaI = 3000 g
2. To find the molarity of a solution, we need to divide the number of moles of solute by the volume of the solution in liters. The equation is:
Molarity (M) = Moles (mol) / Volume (L)
Converting cm3 to L, we divide by 1000. So, the volume in L is:
Volume (L) = 102 cm3 / 1000 = 0.102 L
The moles of C6H12O6 can be calculated using its molar mass. C6H12O6 has a molar mass of 180.18 g/mol. So:
Moles (mol) = Mass (g) / Molar Mass (g/mol) = 450.0 g / 180.18 g/mol = 2.498 mol
Substituting the given values into the molarity equation, we have:
Molarity (M) = 2.498 mol / 0.102 L = 24.5 M
Rounding the answer to the correct number of significant digits, we get:
Molarity = 25 M
3. To find the number of moles of Sr(NO3)2 required in the preparation of a 30.5 M solution with a volume of 20.50 L, we can use the molarity equation:
Molarity (M) = Moles (mol) / Volume (L)
Rearranging the equation, we have:
Moles (mol) = Molarity (M) x Volume (L)
Substituting the given values, we have:
Moles (mol) = 30.5 M x 20.50 L = 626.25 mol
Rounding the answer to the correct number of significant digits, we get:
Moles of Sr(NO3)2 = 630 mol