Answer:
The amount of drug left in his body at 7:00 pm is 315.7 mg.
Explanation:
First, we need to find the amount of drug in the body at 90 min by using the exponential decay equation:

Where:
λ: is the decay constant = 
: is the half-life of the drug = 3.5 h
N(t): is the quantity of the drug at time t
N₀: is the initial quantity
After 90 min and before he takes the other 200 mg pill, we have:

Now, at 7:00 pm we have:

Therefore, the amount of drug left in his body at 7:00 pm is 315.7 mg (from an initial amount of 400 mg).
I hope it helps you!
the results from the breakdown of proteins and amino acids causing a foul smell
Answer:
D
Explanation:
Since [pKa = - log Ka]....hence..,the larger the Ka value,the stronger the acid is..so this means that the pKa is vice versa
Saying that the smaller the pKa value..the stronger the acid is.
Explanation:
Put the pan into a water-containing dish and mix well. Now use a strainer to transfer the solution into another jar. The salt should disappear in it.
And using a tube with a filtrate, transfer the salts that has sand into another bottle with a filtrate. Therefore the sand is split. Eventually, when all the water vaporizes and the salt stays in the bottle, leave the extra solvent and heat it.
True.
A mixture is composed of two or more pure substance that are physically combined but are not combined chemically and thus no electrons (of their atoms) are involved.
The primary properties of a mixture include:
1. The components of a mixture are easily separated
2. The components each keep their original properties.
3. The proportion of the components may vary.
There are two main categories of mixtures:
1. Heterogeneous mixtures - substances are not evenly distributed e.g. oil and water mixture
2. Homogeneous mixtures - substances are evenly distributed throughout the mixture e.g. salt water, air.