Attending an in state college
Answer:
1.14atm
Explanation:
Given parameters:
V1 = 250cm³ ;
1000cm³ = 1dm³; so this is 0.25dm³
P1 = 760torr
760torr = 1atm
V2 = 220cm³ ; 0.22dm³
Unknown:
New pressure = ?
Solution:
To solve this problem, we apply Boyle's law and we use the expression below:
P1 V1 = P2V2
The unknown is P2;
1 x 0.25 = P2 x 0.22
P2 = 1.14atm
There are two valence electrons.
ANSWER:
4 a) Specific elements have more than one oxidation state, demonstrating variable valency.
For example, the following transition metals demonstrate varied valence states:
,
,
, etc.
Normal metals such as
also show variable valencies. Certain non-metals are also found to show more than one valence state 
4 b) Isotopes are members of a family of an element that all have the same number of protons but different numbers of neutrons.
For example, Carbon-14 is a naturally occurring radioactive isotope of carbon, having six protons and eight neutrons in the nucleus. However, C-14 does not last forever and there will come a time when it loses its extra neutrons and becomes Carbon-12.
5 a)
→
5 b)
→ 
5 c)
→
(already balanced so don't need to change)
5 d)
→
5 e)
→ 
EXPLANATION (IF NEEDED):
1. Write out how many atoms of each element is on the left (reactant side) and right (product side) of the arrow.
2. Start multiplying each side accordingly to try to get atoms of the elements on both sides equal.
EXAMPLE OF BALANCING: