Answer:
24382 J
162790 J
Explanation:
At 0°C, ice requires a certain amount of heat/energy to break its certain bonds and change its state into liquid water. This amount of heat per gram of ice is known as the latent heat of fusion of ice. And this heat is already detrmined and is equal to 334 J/g. Similarly, For water to convert into vapor at 100°C, it requires a certain amount of heat/energy to break its certain bonds and change its state into gas/vapor. This amount of heat per gram of water is known as the latent heat of vaporization of water, and it is equal to 2230 J/g.
Now, for one gram ice, 334 J heat is required for melting, hence for 73g of ice, 73x334 = 24382 J of heat is required.
Now, for one gram water, 2230 J heat is required for melting, hence for 73g of water, 73x2230 = 162790 J of heat is required.
The answer is 60.3% magnesium, 39.7% oxygen.
Solution:
The chemical equation for the reaction is 2 Mg + O2 → 2 MgO.
Since magnesium reacts completely with oxygen, it is the limiting reactant in the reaction. Hence, we can use the number of moles of magnesium to get the mass of MgO produced:
moles of magnesium = 14.7g / 24.305g mol-1
= 0.6048 mol
mass of MgO = 0.6048mol Mg(2 mol MgO/2mol Mg)(40.3044g MgO/1 mol MgO)
= 24.376g MgO
We can now solve for the percentage of magnesium:
% Mg = (14.7g Mg / 24.376g MgO)*100% = 60.3%
We also use the number of moles of magnesium to get the mass of oxygen consumed in the reaction:
mass of O2 = 0.6048 mol Mg (1mol O2 / 2mol Mg) (31.998g / 1mol O2)
= 9.676g
The percentage of oxygen is therefore
% O2 = (9.676g O2 / 24.376g MgO)*100%
= 39.7%
Notice that we can just subtract the magnesium's percentage from 100% to get
% O2 = 100% - 60.3% = 39.7%
Here, Molar mass of N2O4 = 92.02 g/mol
So, Number of molecules in 1 mole (92.02 g) = 6.023 * 10²³
Number of molecules in 76.3 g = 6.023 * 10²³ / 92.02 * 76.3
= 6.023 * 10²³ / 1.20
= 5 * 10²³
In short, Your Answer would be approx. 5 * 10²³ molecules
Hope this helps!
Answer:
The salt is Zn(NO3)2
When the residue is allowed to cool, its colour changes from yellow to white
The equation of the reaction is; 2Zn(NO3)2(s) --->2ZnO(s) + 4NO2(g) + O2(g)
Explanation:
Decomposition of Zn(NO3)2 is one of the routes by which ZnO is obtained. ZnO is a white insoluble powder which has a yellow colour when hot and a white colour when cold. It is an amphoteric substance used as a white pigment in paints and as a filler for rubber.
In a very pure form, it is used in cosmetic powders and creams as well as in medicinal ointments and lotions.
Also recall that NO2 is a brown gas and oxygen gas rekindles a glowing splint.
A crystalline solid is brittle, has a high melting point, and has low electrical conductivity is ionic bonds between metals and nonmetals.
On the basis of structure, ca F2 is the most brittle
hope this helps
