I don’t know I’m just answering for points I don’t know 12
C is correct.
Please vote my answer brainliest. thanks!
Answer: (3) silicon
Explanation:
Element is a pure substance which is composed of atoms of similar elements.It can not be decomposed into simpler constituents using chemical reactions.Example: Silicon (Si)
Compound is a pure substance which is made from atoms of different elements combined together in a fixed ratio by mass.It can be decomposed into simpler constituents using chemical reactions. Example: ethane 
, propanone 
and water 
Answer:
a) 37.04% b) 37.04% c) 9.63%
Explanation:
The theoretical percent recovery (Tr), is the total percentage of each compound in the sample. Depending on the technique used to recovery the compounds, the percent recovery will be less than the theoretical, because no technique is 100% efficient.
So, to calculate the theoretical, it will be the mass of the compound divided by the mass of the sample multiplied by 100%.
a) Tr = (250 mg)/(675 mg) * 100%
Tr = 37.04%
b) Tr = (250 mg)/(675 mg) * 100%
Tr = 37.04%
c) Tr = (65 mg)/(675 mg) * 100%
Tr = 9.63%
