Name_________________________________
Date_________________
Homework: Calculations of
Concentrations:
In the medical and biological fields, concentrations of solutions are frequently
expressed as the mass percent.
A. For example,
a 5% solution of sodium hydroxide , contains 5 grams of NaOH in 100 grams of
solution.
Calculation:
5grams NaOH
x 100 = 5% NaOH
100g Solution
To
Solve: 5 divided by 100 , multiply
by 100 to get the percentage.
B. For example,
what is the mass percent concentration of a
solution containing 2
grams sodium hydroxide as the
solute , dissolved in 78 grams of water as the solvent to make a solution.
Calculation:
2
2 grams NaOH
x 100
= 2.5% NaOH
2 g Solute + 78 g Solvent
To
Solve: Add (2 + 78= 80) , take 2 divided by 80 , multiply by 100 to get the
percentage.
Homework:
Calculate the mass percent
concentration for the following solutions, SHOW SET UP of ALL PROBLEMS. (When
rounding your final answer, use the rules for Significant figures, the 100 does
not count as a Significant figure.)
- Calculate
the mass percent concentration of a solution
made with 25 grams of Sodium Chloride dissolved in 200 grams of water.
answer_________
- Calculate
the concentration of a solution with 142 grams of H2O2
as the solute and 355grams of water as the solvent.
answer__________
- Calculate
the concentration of a solution with 5 grams of Cl2 as the solute
and 55grams of Nitrogen as the solvent.
answer__________
- Calculate
the mass percent concentration of a solution made with 50.0 grams of Sucrose
dissolved in 200.0 grams of Solution.
answer__________
- Calculate
the mass percent concentration of a solution made with 10.0 grams of salt
dissolved in 300.0 grams of Solution.
answer__________
- Calculate
the concentration of a solution with 2 grams of
I2 as the solute and 28 grams of Alcohol as the solvent.
answer__________
- Calculate
the concentration of a solution with 500 grams of
Helium as the solute and 1.5 Kilograms of Oxygen as the solvent. (Hint –convert Kilograms to grams, the equality is 1000 grams = 1 Kilogram)
answer__________
- Calculate
the concentration of a solution with 5 grams of
Br2 as the solute and 45 grams of water as the solvent.
answer__________
- Calculate
the concentration of 20 grams of alcohol dissolved
in 100 grams of solution.
answer__________
- Calculate
the concentration of a solution with 25 grams of
zinc as the solute and
75 grams of Copper
as the solvent.
answer__________