Answer:

Explanation:
Assume you are using 1 L of water.
Then you are washing 4 L of salty oil.
1. Calculate the mass of the salty oil
Assume the oil has a density of 0.86 g/mL.

2. Calculate the mass of salt in the salty oil

3. Calculate the mass of salt in the spent water

4. Mass of salt remaining in washed oil
Mass = 172 g - 150 g = 22 g
5. Concentration of salt in washed oil

Answer:
Yes, the chemist can determine which compound is in the sample.
Explanation:
In 1 mole of K₂O, the mass of K is 2 × 39.1 g = 78.2 g and the mass of K₂O is 94.2 g. The mass ratio of K to K₂O is 78.2 g / 94.2 g = 0.830.
In 1 mole of K₂O₂, the mass of K is 2 × 39.1 g = 78.2 g and the mass of K₂O₂ is 110.2 g. The mass ratio of K to K₂O₂ is 78.2 g / 110.2 g = 0.710.
If the chemist knows the mass of K and the mass of the sample, he or she must calculate the mass ratio of K to the sample.
- If the ratio is 0.830, the compound is pure K₂O.
- If the ratio is 0.710, the compound is pure K₂O₂.
- If the ratio is not 0.830 or 0.710, the sample is a mixture.
Answer would be B. I provided work on an image attached. Message me if u have any other questions on how to do it
Hello there!
To determine the fraction of the hydrogen atom's mass that is in the nucleus, we have to keep in mind that
a Hydrogen atom has 1 proton and 1 electron.
Protons are in the nucleus while electrons are in electron shells surrounding the nucleus.
The mass of the nucleus will be equal to the mass of 1 proton and we can express the fraction as follows:

So, the fraction of the hydrogen atom's mass that is in the nucleus is
0,9995. That means that almost all the mass of this atom is at the nucleus.
Have a nice day!
Answer:
She should not have multiplied the nitrogen atom by subscript 2.
Explanation:
Chemical formula:
3(NH₄)₂SO₄
Elements present in given formula:
Nitrogen
Hydrogen
Sulfur
Oxygen
Total number of atoms of elements:
N = 3×1×2 = 6
H = 4×2×3 = 24
S = 1×3 = 3
O = 3×4 = 12
The number nitrogen atoms are six. Elena did mistake by counting the number of nitrogen. She should didn't multiplied the nitrogen atom by subscript 2.