Moles of Na_2O
- Given mass/Molar mass
- 35/62
- 0.56mol
2 mols Na_2O produces 1 mol sodium carbonate.
1 mol sodium oxide produces 0.5mol sodium carbonate
Moles of sodium carbonate
Molar mass
- 2(23)+12+3(16)
- 46+12+48
- 106g/mol
Mass
Answer: D may be equal to, greater than, or less than the total amount of the reactants.
Explanation:
<span>This is rather a case of purification of impure copper or extraction of Cu from its alloy. You need to place the impure copper rod on the positive electrode (Anode) usualyy made of carbon rod, whereby oxidation reaction takes place: Cu (s) -------> Cu2+ (aq) + 2e- That is to say the impure cooper dissolves into solution. The copper (II) ions move to the negative electrode (cathode) usually made of pure copper rod. At the cathode, the Cu2+ ions are reduced : Cu2 (aq)+ + 2e- -----> Cu(s). That is to say the copper (II) ions are deposited as solid copper atoms onto the cu-rod electrode. In this way impure copper is deposited as pure copper onto the copper cathode</span>
Answer:
C) Potassium, K, and calcium, Ca
Explanation:
Given pair of elements:
Ni and Cu
Potassium and Ca
Nitrogen and oxygen
Solution:
We know that number of protons and number of electrons are always equal and number of electron or number of proton is called atomic number.
Number of protons given elements:
Ni number of protons = 28
Copper number of protons = 29
Combine number of protons = 57
K number of protons = 19
Ca number of protons = 20
Combine number of protons = 39
Ni number of protons = 7
O number of protons = 8
Combine number of protons = 15
Thus, option C is correct.