Answer:
0.712 mol
Explanation:
The easiest way to do this is to use a proportion.
1 mol of copper = 63.5 grams (check this using your periodic table).
x mol of copper = 45.2 grams
1/x = 63.5 / 45.2 Cross multiply
63.5 x = 1 * 45.2 Divide by 63.5
x = 45.2/63.5
x = 0.712 mol Answer to 3 sig digs
Answer:
7.
Explanation:
A neutral solution has a pH=7.
A basic solution has a pH>7.
An acidic solution has a pH<7.
Bronze metal is harder and more malleable than copper. It is also conducts property of ductility, so it can be easily shaped as a statue.
<span>12.4 g
First, calculate the molar masses by looking up the atomic weights of all involved elements.
Atomic weight manganese = 54.938044
Atomic weight oxygen = 15.999
Atomic weight aluminium = 26.981539
Molar mass MnO2 = 54.938044 + 2 * 15.999 = 86.936044 g/mol
Now determine the number of moles of MnO2 we have
30.0 g / 86.936044 g/mol = 0.345081265 mol
Looking at the balanced equation
3MnO2+4Al→3Mn+2Al2O3
it's obvious that for every 3 moles of MnO2, it takes 4 moles of Al. So
0.345081265 mol / 3 * 4 = 0.460108353 mol
So we need 0.460108353 moles of Al to perform the reaction. Now multiply by the atomic weight of aluminum.
0.460108353 mol * 26.981539 g/mol = 12.41443146 g
Finally, round to 3 significant figures, giving 12.4 g</span>
