I believe its a...................
Answer:
The reaction is exothermic (option 4)
Explanation:
P4 + 5O2 → P4O10 + 712 kcal
In chemical reactions heat can be absorbed or released:
⇒in the first case, when heat is absorbed, this is called an endothermic reaction. The products have more energy than the reactants. The reaction requires or absorbs energy from it's surroundings. That means that in this reaction energy , in the form of heat, will be absorbed by the reactants.
⇒ when heat is released, this is called an exothermic reaction. The reactants have more energy than the products. The reaction gives or releases energy to it's surroundings. That means that in this reaction energy , in the form of heat, will be released by the reactants.
in the case of P4 + 5O2 → P4O10 + 712 kcal
We notice that on the right side, which is the product side, there is a positive amount of energy. This means that the energy is released by the the reactants, in this reaction. <u>The reaction is exothermic.</u>
.
Explanation:
Molar mass of
= 39.1 + 35.5 + 3(16.0) = 122.6 g
Molar mass of KCl = 39.1 + 35.5 = 74.6 g
Molar mass of
= 32.0 g
According to the equation, 2 moles of
reacts to give 3 moles of oxygen.
Therefore, 2 (122.6) = 245.2 g of
will give 3 (32.0) = 96.0 g of oxygen. Thus, 245.2 g of
gives 96.0 g of oxygen.
(a) Calculate the amount of oxygen given by 2.72 g of
as follows.
of
(b) Calculate the amount of oxygen given by 0.361 g of
as follows.
of
c) Calculate the amount of oxygen given by 83.6 kg
as follows.
of 
Convert kg into grams as follows.
= 32731 g of 
(d) Calculate the amount of oxygen given by 22.5 mg of
as follows.

Convert mg into grams as follows.
of 
I am going to go with,
0.10 g/mL
0.0700 g/mL
0.0447 g/mL
I don't know if this is the correct answer, but I am 80% sure that it may be.
:) :)
Answer:

Explanation:
The work function of the sodium= 495.0 kJ/mol
It means that
1 mole of electrons can be removed by applying of 495.0 kJ of energy.
Also,
1 mole =
So,
electrons can be removed by applying of 495.0 kJ of energy.
1 electron can be removed by applying of
of energy.
Energy required =
Also,
1 kJ = 1000 J
So,
Energy required =
Also,
Where,
h is Plank's constant having value
c is the speed of light having value
So,
Also,
1 m = 10⁻⁹ nm
So,
