Answer:- The right choice is A. 
.
Solution:- Latent heat of fusion means the heat required to melt the solid at constant temperature means there is no change in temperature only the solid changes to liquid. So, it is a solid to liquid phase change.
where q is the heat required to convert solid to liquid, m is the mass and 
is the latent heat of fusion.
From given info, 550 kJ that is 550000 J of heat is required to melt 14 kg of solid at 262K temperature. Let's rearrange the equation for latent heat of fusion and plug in the values in it.
= 
If we round this value to two sig figs and write in scientific notations then it becomes .
So, the right choice is A. .
Answer : The molecular weight of a gas is, 128.9 g/mole
Explanation : Given,
Density of a gas = 5.75 g/L
First we have to calculate the moles of gas.
At STP,
As, 22.4 liter volume of gas present in 1 mole of gas
So, 1 liter volume of gas present in 
mole of gas
Now we have to calculate the molecular weight of a gas.
Formula used :
Now put all the given values in this formula, we get the molecular weight of a gas.
Therefore, the molecular weight of a gas is, 128.9 g/mole
Answer:
Background
Solids – relatively rigid, definite volume and shape. In a solid, the atoms and molecules are attached to each other. ...
Liquids – definite volume but able to change shape by flowing. In a liquid, the atoms and molecules are loosely bonded. ...
Gases – no definite volume or shape
Answer:
2.08 moles
Explanation:
number of molecules = mass / molecular mass of SO₄
number of molecules = 200 g / 96.06 g/mol
number of molecules ≈ 2.08
Answer:
5 molecules of calcium phosphate 15 atoms of calcium 10 atoms of phosphate 40 atoms of oxygen
4
Explanation:
these are the answers for 77 and 78
