Its 3, because you cant filter out or evaporate an element from a compound, for example water mixed with sand is a ''mixture and the sand can be filtered out, or water with dissolved sugar is also a 'mixture' and the water can be evaporated.
Answer:

Explanation:
We will need a balanced chemical equation with masses, moles, and molar masses.
1. Gather all the information in one place:
M_r: 2.016 17.03
3H₂ + N₂ ⟶ 2NH₃
m/g: 6.33 × 10⁻⁴
2. Calculate the moles of H₂

3. Calculate the moles of NH₃
The molar ratio is 2 mol NH₃/3 mol H₂.

4. Calculate the molecules of NH₃
There are 6.022 × 10²³ molecules of NH₃/1 mol NH₃.

<u>Answer:</u> The mass of sulfur dioxide gas at STP for given amount is 16.8 g
<u>Explanation:</u>
At STP conditions:
22.4 L of volume is occupied by 1 mole of a gas.
So, 5.9 L of volume will be occupied by = 
Now, to calculate the mass of a substance, we use the equation:

Moles of sulfur dioxide gas = 0.263 mol
Molar mass of sulfur dioxide gas = 64 g/mol
Putting values in above equation, we get:

Hence, the mass of sulfur dioxide gas at STP for given amount is 16.8 g
Answer:
I think it is B. takes place slowly. hope this helps!
Answer:
10Na + 2NaNO3 → 6Na2O + N2
Explanation: