Answer:
About 7.9 L.
Explanation:
We can utilize the ideal gas law. Recall that:

Because the amount of carbon dioxide does not change, we can rearrange to formula to:

Because the right-hand side stays constant, we have that:

Hence substitute initial values and known final values:

Therefore, the final volume is about 7.9 L.
I need more characters but it is b
Answer:
520 kg
Explanation:
Let's consider the combustion of isooctane.
C₈H₁₈(l) + 12.5 O₂(g) → 8 CO₂(g) + 9 H₂O(l)
We can establish the following relations:
- 1 mL of C₈H₁₈ has a mass of 0.690 g (ρ = 0.690 g/mL).
- The molar mass of C₈H₁₈ is 114.22 g/mol.
- The molar ratio of C₈H₁₈ to O₂ is 1:12.5.
- The mole fraction of O₂ in air is 0.21.
- The molar mass of air is 28.96 g/mol.
50 L of isooctane require the following mass of air.

PV = nRT
P is pressure, V is volume, n is number of moles, R is the gas constant, T is temperature in K
(2.85 atm)(12.5 L) = (n)(.08206)(27 C + 273)
n = 1.45 moles x 35.45 grams / mol Cl2 = 51.3 grams
I'm guessing you have to balance these.
I took a picture of my working out.
Answer to the first one = 2HCl+CaCO3=CaCl2+H20+CO2
So basically just add a big 2 in front of the first HCl
Answer to second one = 2Ni + O2 = 2NiO
So basically in this one just add a big 2 in front of both of the Ni