Answer:
Number of moles = 0.05 mol
Explanation:
Given data:
Mass of Pb = 10.5 g
Number of moles of Pb = ?
Solution:
Formula:
Number of moles = mass/molar mass
Molar mass of Pb is 207.2 g/mol.
Now we will put the values in formula.
Number of moles = 10.5 g/207.2 g/mol
Number of moles = 0.05 mol
6.4 times 10^-7 is the answer because you are moving your decimal places to the left so it will be negative 7
Answer:
6. O₂ + Cu —> CuO
7. H₂ + Fe₂O₃ —> H₂O + Fe
8. O₂ + H₂ — > H₂O
9. H₂S + NaOH —> Na₂S + H₂O
10. Al + HCl —> H₂ + AlCl₃
Explanation:
6. Oxygen gas react with solid copper metal to form copper(II) oxide
Oxygen gas => O₂
Copper => Cu
copper(II) oxide => CuO
The equation is:
O₂ + Cu —> CuO
7. hydrogen gas and iron(III) oxide powder react to form liquid water and solid iron power
hydrogen gas => H₂
Iron(III) oxide => Fe₂O₃
Water => H₂O
Iron => Fe
The equation is:
H₂ + Fe₂O₃ —> H₂O + Fe
8. Oxygen gas react with hydrogen gas to form liquid water
Oxygen gas => O₂
hydrogen gas => H₂
Water => H₂O
The equation is:
O₂ + H₂ — > H₂O
9. Hydrogen sulphide gas is bubbled through a sodium hydroxide solution to produce sodium sulphide and liquid water
hydrogen sulphide => H₂S
sodium hydroxide => NaOH
Sodium sulphide => Na₂S
Water => H₂O
The equation is:
H₂S + NaOH —> Na₂S + H₂O
10. Hydrogen gas and aluminum chloride solutions are produced when solid aluminum react with hydrochloric acid
Aluminum => Al
Hydrochloric acid => HCl
hydrogen gas => H₂
Aluminum chloride => AlCl₃
The equation is:
Al + HCl —> H₂ + AlCl₃
<span>The copper would go under oxidation since it will be losing two electrons. Copper starts out with an oxidation number of zero, but in order to balance the compound of CuO with the Oxygen having an oxidation number of -2, a positive 2 is required</span>
