A
nswer: -
C. Energy is released by the reaction
Explanation:-
An exothermic reaction is one in which during the progress of the reaction heat is evolved.
So energy is released by the reaction.
It cannot be created as energy is neither created nor destroyed as per the Law of conservation of energy. Energy is not transferred either.
The energy released during the progress of the reaction originates from the chemical bonds of the reactants as they break during their conversion into products.
Since nickles atomicnumber is 28, that means it has 28 protons, which are positively charged. To cancel out the positive charge and make it nuetral, there isalso 28 electrons which are negatively charged.
Nickel has 31 neutrons because an atoms mass is the number of protons + neutrons. The # of protons is 28. The mass # is 59. So, there are 31 neutrons.
Answer:
5010J
Explanation:
The following data were obtained from the question:
Mass (m) = 15g
Heat of fusion (ΔHf) = 334J/g
Heat required (Q) =..?
The heat energy required to melt the ice can be obtained as follow:
Q = m·ΔHf
Q = 15 x 334
Q = 5010J
Therefore, the heat energy required to melt the ice is 5010J.
Answer:
(a) oxygen
(b) 154g (to 3sf)
(c) 79.9% (to 3sf)
Explanation:
mass (g) = moles × Mr/Ar
note: eqn means chemical equation
(a)
moles of P = 84.1 ÷ 30.973 = 2.7152 moles
moles of O2 = 85÷2(16) = 2.65625 moles
Assuming all the moles of P is used up,
moles of O2 / moles of phosphorus = 5/4 (according to balanced chemical eqn)
moles of O2 required = 5/4 × 2.7152moles = 3.394 moles (more than supplied which is 2.65625moles)
therefore there is insufficient moles of O2 and the limiting reactant is oxygen.
(b)
moles of P2O5 produced
= 2/5 (according to eqn) × 2.7152
= 1.08608moles
mass of P2O5 produced
= 1.08608 × [ 2(30.973) + 5(16) ]
= 154.164g
= approx. 154g to 3 sig. fig.
(c)
% yield = actual/theoretical yield × 100%
= 123/154 × 100%
= 79.870%
= approx. 79.9% (to 3sf)
A. The cell will not be able to maintain a stable internal environment.
