Answer:
81.71%
Explanation:
One mole of propane contains 3 moles of carbon atoms and 8 moles of hydrogen atoms, as seen from the molecular formula of
. In order to calculate the percent of carbon in propane by mass, we need to remember that %w/w (or percent mass) formula states that:

That is, we need to divide the mass of the component of interest by the total mass of the compound and multiply by 100 to obtain the percentage.
For simplicity, let's take 1 mole of propane and find the mass of 1 mole (hence, we'll be finding the molar mass of propane). To do that, we add the 3 molar masses of carbon and 8 molar masses of hydrogen to obtain a total of:

Now that we have the molar mass of propane, we also need to find the total mass of carbon in 1 mole of propane. We know that we have a total of 3 moles of carbon which corresponds to:

Dividing the mass of carbon present by the total mass of the compound will yield the mass percentage as defined by the formula we introduced:

Answer:
False
Explanation:
Science is not based on primarily on peoples opinions and views of the subject matter whereas science is based on empirical observations and research for its validity.
<u>Science aims to find answers to human questions related to the natural world through their research observation and experiments. Scientists and researchers provide valid proof of human questions so that people can trust them.</u>
Science can change people's opinions regarding the natural world with valid proof and observational theories but science is not based on people's opinion.
Hence, the given statement is "false".
Answer:
The answer to your question is 8.75 x 10 ²⁵ atoms of Magnesium
Explanation:
Data
Atomic mass of Magnesium = 24.31 g
Atoms of magnesium = 3.60 x 10²⁴
Process
Solve this porblem using a rule of three
1 atom of Magnesium --------------- 24.31 g
3.60 x 10²⁴ ---------------- x
x = (3.60 x 10²⁴ x 24.31) / 1
x = 8.75 x 10 ²⁵ atoms
It would be +7 oxidation number.
[All compounds are zero]
Al is in group III [ or 13 depending on the system ] so the oxidation state is 3.
You have 12 O at -2 each for-24. That leaves you at -24+3=-21. So, 3 Cl atoms must be +21 to balance the -21 there which makes +21/3 or +7 for each Cl.