Answer:- 3. 
and 
Explanations:- An empirical formula is the simplest whole number ratio of atoms of each element present in the molecule/compound.
For example, the molecular formula of benzene is 
. The ratio of C to H in it is 6:6 that could be simplified to 1:1. So, an empirical formula of benzene is CH.
In the first pair, the ratio of C to H in first molecule is 2:4 that could be simplified to 1:2 and the empirical formula is 
. In second molecule the ratio of C to H is 6:6 and it could be simplified to 1:1. and the empirical formula is CH. Empirical formulas are different for both the molecules of first pair and so it is not the right choice.
In second pair, C to H ratio in first molecule is 1:2, so the empirical formula is . The C to H ratio for second molecule is 1:4, so the empirical formula is 
. Here also, the empirical formulas are not same and hence it is also not the right choice.
In third pair, C to H ratio in first molecule is 1:3, so the empirical formula is . In second molecule the C to H ratio is 2:6 and it is simplified to 1:3. So, the empirical formula for this one is also . Hence. this is the correct choice.
In fourth pair, first molecule empirical formula is CH. Second molecule has 2:4 that is 1:2 mole ratio of C to H and so its empirical formula is . As the empirical formulas are different, it is not the right choice.
So, the only and only correct pair is the third one. 3. and
Answer:
D
Explanation:
the answer is d white precipitate
The mass of water that contains 2.5×10²⁴ atoms of Hydrogen is 74.79 g
<h3>Avogadro's hypothesis </h3>
From Avogadro's hypothesis,
6.02×10²³ atoms = 2 g of H
Therefore,
2.5×10²⁴ atoms = (2.5×10²⁴ × 2) / 6.02×10²³
2.5×10²⁴ atoms = 8.31 g of H
<h3>How to determine the mass of water </h3>
- 1 mole of water H₂O = (2×1) + 16 = 18 g
- Mass of H in 1 mole of water = 2 g
2 g of H is present in 18 g of water.
Therefore,
8.31 g of H will be present in = (8.31 × 18) / 2 = 74.79 g of water.
Thus, 2.5×10²⁴ atoms of Hydrogen is present in 74.79 g of water.
Learn more about Avogadro's number:
brainly.com/question/26141731
Answer:
12.9
Explanation:
From the question given, the concentration of the hydroxide ion is given:
[OH^-] = 1.4 x 10^ -13M
pOH =?
pOH = —Log [OH^-]
pOH = —Log 1.4 x 10^ -13
pOH = 12.9
I think correct answer is C.Jet stream would be displaced southwards causing heavy rain and flooding
The statement that is a likely impact of stronger than normal trade winds in the Pacific Northwest to the United States is Jet stream would be displaced southwards causing heavy rain and flooding.
