Answer:
Al2O3 + 3Mg ===》 3MgO + 2Al
Explanation:
Reaction of aluminium oxide with magnesium metal would form magnesium oxide and aluminium metal.
Balancing the stoichiometric equation, the number of atoms at the reactant must be equal to the number of atoms at the product so that law of conservation of matter must hold.
Al203 + 3Mg ====》 3MgO + 2Al
2 aluminium at reactant = 2 aluminium at product
3 oxygen at reactant = 3 oxygen at product
3 magnesium at reactant = 3 magnesium at product.
M=energy transferred/ (temperature change*specific heat)
M= 5650/(26.6*1.0)
M=212g
Answer:
time is 3333.33 min or 55.55 hr
Explanation:
given data
reactor operating = 1 MW
negative reactivity = $5
power = 1 miliwatt
to find out
how long does it take
solution
we know here power coefficient that is
power coefficient = 
power coefficient = 1
so time required to reach power is
power = reactivity × time / power coefficient + reactor operating
1 ×
= -5 t / 1 + 1 × 
5t =
- 
t = 199999.99 sec
so time is 3333.33 min or 55.55 hr
Answer:
B.
It will be greater than 10 J.
Explanation:
The total mechanical energy of an object is the sum of its potential energy (PE) and its kinetic energy (KE):
E = PE + KE
According to the law of conservation of energy, when there are no frictional forces on an object, its mechanical energy is conserved.
The potential energy PE is the energy due to the position of the object: the highest the object above the ground, the highest its PE.
The kinetic energy KE is the energy due to the motion of the object: the highest its speed, the largest its KE.
Here at the beginning, when it is at the top of the roof, the baseball has:
PE = 120 J
KE = 10 J
So the total energy is
E = 120 + 10 = 130 J
As the ball falls down, its potential energy decreases, since its height decreases; as a result, since the total energy must remain constant, its kinetic energy increases (as its speed increases).
Therefore, when the ball reaches the ground, its kinetic energy must be greater than 10 J.