Answer:

Explanation:
2C₄H₁₀ + 13O₂ ⟶ 8CO₂ + 10H₂O
n/mol: 4.3
13 mol of O₂ react with 2 mol of 2C₄H₁₀

Answer: 28.4 g of aluminum oxide is produced by the reaction of 15.0 g of aluminum metal
Explanation:
To calculate the moles :
The balanced chemical equuation is:
According to stoichiometry :
4 moles of
produce == 2 moles of
Thus 0.556 moles of
will produce=
of
Mass of
Thus 28.4 g of aluminum oxide is produced by the reaction of 15.0 g of aluminum metal.
Independent Variable: a variable that you can change in an experiment
Dependent Variable: something that changes as you change the independent variable
control variable: something that is not changed throughout the experiment
Answer:
Rb+
Explanation:
Since they are telling us that the equivalence point was reached after 17.0 mL of 2.5 M HCl were added , we can calculate the number of moles of HCl which neutralized our unknown hydroxide.
Now all the choices for the metal cation are monovalent, therefore the general formula for our unknown is XOH and we know the reaction is 1 equivalent acid to 1 equivalent base. Thus we have the number of moles, n, of XOH and from the relation n = M/MW we can calculate the molecular weight of XOH.
Thus our calculations are:
V = 17.0 mL x 1 L / 1000 mL = 0.017 L
2.5 M HCl x 0.017 L = 2.5 mol/ L x 0.017 L = 0.0425 mol
0.0425 mol = 4.36 g/ MW XOH
MW of XOH = (atomic weight of X + 16 + 1)
so solving the above equation we get:
0.0425 = 4.36 / (X + 17 )
0.7225 +0.0425X = 4.36
0.0425X = 4.36 -0.7225 = 3.6375
X = 3.6375/0.0425 = 85.59
The unknown alkali is Rb which has an atomic weight of 85.47 g/mol