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:
balance by putting 2 next to HF
Answer: Manholes are usually round, primarily because roundness is the best shape to resist the compression of the earth; covers are round because they are easier to manufacture than square or rectangular shapes, they are easier to move by rolling, and they can't fall into the opening.
Explanation:
Answer:
The water molecules slow down, stronger attractions form between them, and the molecules are pulled closer together.
Explanation:
In solids the packing of the particles is closer and tighter thus increasing the intermolecular attraction. This makes solids rigid with a definite shape, size and volume. On the other hand in liquids the packing of the particles is loose thus decreasing the intermolecular attraction. This makes liquids able to flow, and takes the shape and volume of the container in which they are placed.
