Question

1. A form of children's ibuprofen is sold as a suspension (in which the drug is suspended in water) that contains 100 mg of ibuprofen/5mL. Showing all of your work and using at least two conversion steps, convert this concentration to g/L.

Report your answer to the correct number of significant figures and with correct units.

2. Determine which type of process is described by the following statement:

Liquid propane combines with oxygen and produces heat when ignited with a spark.

A.) phase change

B.)chemical reaction

C.) physical change

D.) endothermic reaction

Answer 1

1) we have 100 mg of ibuprofen per 5 ml it means,

i) (100 mg / 5 mL) = 20 mg/mL

ii) we know that 1 g = 1000 mg and 1 L = 1000 mL

iii) therefore : 100 mg = ( 100 / 1000 ) gm = 0.1 gm

iv) 5 mL = ( 5 / 1000 ) L = 0.005 L

iv) hence (100 mg / 5 ml) = ( 0.1 gm / 0.005 L ) = 20 gm/L

we have 20 gm of ibuprofen per Liter.

2) Balanced equation for given process is

C3H8 (l) + 5O2(g) -------> 3CO2(g) + 4H2O(g) + Heat

It is a combustion reaction which is exothermic in nature. Heat will be released.

Answer is B) Chemical reaction.

Explanation ; In A) phase and C) physical change, reactant remains the same, it does not changes. In D) endothermic reaction heat will get absorbed. In B) any chemical reaction, reactant changes itself into products with different chemical properties.