You have been asked to mix up some 70% isopropyl alcohol solution.

You have been asked to mix up some 70% isopropyl alcohol solution.
You have 95% isopropyl alcohol solution on hand. How many mL do you have to add to 100 mL of pure water to
create a 70% solution?



A chemist needs to produce a 40% acid mixture. She has 25% strength solution and 80% strength solution on hand.
Rounding to the nearest thousandth (3 decimal places; nearest mL), how many liters of 25% solution does she add to create 1 liter of the 40% strength mixture?



Dextrose 5% in water (D5W) is useful to provide liquids and energy to a body via IV. Anything over 5% concentration is
hypertonic (can draw water out of cells) and can only be infused slowly.
The doctor has ordered Dextrose 10% in water (D10W) to be administered.
You have a partial-fill container with 400 mL of Dextrose 30% in water (D30W), and must dilute it to 10%.
You have no pure sterile water on hand, so will use D5W instead.
How many mL of D5W should you add to the container to dilute the D30W to D10W?


The octane rating for gasoline says how resistant it is to igniting under compress, before the spark-plug ignites.
An octane rating of X says it has the equivalent knocking rating of a mixture of X% iso-octane and the rest n-heptane.
For this problem, assume that gasoline actually is composed of iso-octane and n-heptane.
How many gallons of 82 octane gasoline must be combined with 9 gallons of 87 octane gasoline to make 85 octane gasoline?


How many mg of hydrocortisone* are in 75 grams of a 2% strength ointment combined with 100 grams of a 0.75% strength ointment?
Careful, the answer is asked for in mg, not grams.
*A synthetic form of the stress hormone cortisol, used as an immunosuppressant to treat inflammation and allergies.

How mL of fat are there in 2 liters of 2% Milk (by volume)?