3 At room temperature and pressure (rtp), which of the substances listed below is:
a a solid element?
b a liquid element?
ca gaseous mixture!
d a solid mixture?
e a liquid compound?
f a solid compound?
Bromine, carbon dioxide, helium, steel, air, oil,
marble, copper, water, sand, tin, bronze, mercury,
salt.

C

Explanation:

answer: a tank of height h is filled with water and sits on the ground. water squirts from a hole at a height y above the ground and has a range r. for two y values, 0 and h, r is zero. determine the value of y for which the range will be a maximum.

explanation:

acid rain does not usually kill trees directly. instead, it is more likely to weaken the trees by damaging their leaves, limiting the nutrients available to them, or poisoning them with toxic substances slowly released from the soil. the main atmospheric pollutants that affect trees are nitrates and sulphates.