Answer:
3.81 g Pb
Explanation:
When a lead acid car battery is recharged, the following half-reactions take place:
Cathode: PbSO₄(s) + H⁺ (aq) + 2e⁻ → Pb(s) + HSO₄⁻(aq)
Anode: PbSO₄(s) + 2 H₂O(l) → PbO₂(s) + HSO₄⁻(aq) + 3H⁺ (aq) + 2e⁻
We can establish the following relations:
- 1 A = 1 c/s
- 1 mole of Pb(s) is deposited when 2 moles of e⁻ circulate.
- The molar mass of Pb is 207.2 g/mol
- 1 mol of e⁻ has a charge of 96468 c (Faraday's constant)
Suppose a current of 96.0A is fed into a car battery for 37.0 seconds. The mass of lead deposited is:
Answer:
b Fuel for fusion reactors can be extracted from ocean water.
Explanation:
The fuel is deuterium, which makes up 0.02% of the hydrogen atoms in water. The oceans contain more than a billion cubic kilometres of water, so that's a lot of deuterium.
a is wrong. The fuel for fusion reactors is deuterium.
c is wrong. There is much research, but there are no large-scale fusion reactors in operation.
d is wrong. Fusion reactors do not produce radioactive waste as spent fuel. Most of the radioactive waste would be the reactor core itself.
The compound's molecular formula is C2H6. This is obtained by:
mass moles divided by smallest moles
C 32g 32/12 = 2.67 1
H 8g 8/1.01 = 7.92 approx. 3
Next, divide both terms by the smallest number of moles, 2.67. This gives 1 and 3. So the empirical formula is CH3 which has a molar mass of 15g/mol. Given the molar mass of the molecular formula as 30g/mole, we can calculate the factor by which to multiply the subscripts of CH3.
X = molar mass of molecular formula / molar mass of empirical formula = 30/15
X=2
So (CH3)2 is C2H6.
Hg = (3.2 : 4.2) x 100% = 76.19%
O = (1 : 4.2) x 100% = 23.81%
Explanation:
It is given that, Jill and George both push on the same cart with 20 units of force, but in opposite directions.
We know that when two forces are acting in opposite direction, they cancel out each other.
Net force in this case = +20 N - 20 N = 0
It means the net force is 0. As a result, the cart will not move. The forces acting on the cart are balanced.
