Answer:
180 mg
Explanation:
For a first-order reaction, we can calculate the amount of aspirine (A) at a certain time (t) using the following expression.
where,
k: rate constant
A₀: initial amount
If we know the half-life () we can calculate the rate constant.
When t = 4 h and A₀ = 400 mg, A is:
Explanation:
Heterogeneous mixture is a mixture with non-uniform composition.
The properties of the mixture like concentration may change for different parts of the mixture.
Colloids contain solute particles of size .The presence of these particles makes the mixture heterogeneous.
Suspensions contain solute particles of size .These particles settle to the bottom of the mixture which makes the composition of the bottom different from the top.
So,colloids and suspensions are two types of heterogeneous mixtures.