Answer:
1. she requires the anode and cathode
3. the electrolyte : the increase amount of salty water she uses will determine the transfer in of electron needed to power the bulb
4. the battery she uses must be able to power a torch
5. the bulb could be a torch bulb or a bulb lesser than 25 watts
Answer:
H 13.8mol CO2
Explanation:
we know that per 1 mol there is 6.022x10^23 molecules
so divide 8.23x10^22/ AVG # ( # above) we get 13.8mol of CO2 not to be confused with A
Answer:
K₂Cr₂O₇(s) ⇒ 2 K⁺(aq) + Cr₂O₇²⁻(aq)
Explanation:
Potassium dichromate (K₂Cr₂O₇) is a strong electrolyte, that is, when dissolved in water (the medium), it dissociates in cation potassium (K⁺) and anion dichromate (Cr₂O₇²⁻). The balanced dissociation equation is:
K₂Cr₂O₇(s) ⇒ 2 K⁺(aq) + Cr₂O₇²⁻(aq)
Answer : The molecular weight of a substance is 157.3 g/mol
Explanation :
As we are given that 7 % by weight that means 7 grams of solute present in 100 grams of solution.
Mass of solute = 7 g
Mass of solution = 100 g
Mass of solvent = 100 - 7 = 93 g
Formula used :
where,
= change in freezing point
= temperature of pure water =
= temperature of solution =
= freezing point constant of water =
m = molality
Now put all the given values in this formula, we get
Therefore, the molecular weight of a substance is 157.3 g/mol
Answer:
Mass of Fe produced = 4.468 g
Explanation:
Given data:
Mass of Fe produced = ?
Mass of Fe₂O₃ react = 6.50 g
Solution:
Chemical equation:
2Fe₂O₃ → 4Fe + 3O₂
Number of moles of Fe₂O₃ ;
Number of moles = mass/molar mass
Number of moles = 6.50 g/159.69 g/mol
Number of moles = 0.04 mol
Now we will compare the moles of iron and ironoxide.
Fe₂O₃ : Fe
2 : 4
0.04 : 4/2×0.04 = 0.08 mol
Mass of iron produced:
Mass = number of moles × molar mass
Mass = 0.08 mol × 55.85 g/mol
Mass = 4.468 g