Lithium dihydrogen phosphate
Answer: 1and 4
Explanation: iron is an element not an alloy. An ionic lattice is not bonded covalently.
Answer:
Approximately 6.81 × 10⁵ Pa.
Assumption: carbon dioxide behaves like an ideal gas.
Explanation:
Look up the relative atomic mass of carbon and oxygen on a modern periodic table:
Calculate the molar mass of carbon dioxide
:
.
Find the number of moles of molecules in that
sample of
:
.
If carbon dioxide behaves like an ideal gas, it should satisfy the ideal gas equation when it is inside a container:
,
where
is the pressure inside the container.
is the volume of the container.
is the number of moles of particles (molecules, or atoms in case of noble gases) in the gas.
is the ideal gas constant.
is the absolute temperature of the gas.
Rearrange the equation to find an expression for
, the pressure inside the container.
.
Look up the ideal gas constant in the appropriate units.
.
Evaluate the expression for
:
.
Apply dimensional analysis to verify the unit of pressure.
Answer: HBr has the lowest rate of effusion at a given temperature.
Explanation: The effusion rate usually increases with increase in temperature because the kinetic energy of the gaseous molecules increases. But it was not true for gases having heavier mass. This was explained by Graham's Law.
Graham's Law states that the rate of effusion of a gas is inversely proportional to the square root of its molecular weight.

We are given different gases with different Molecular masses. The gas having larger Molecular mass will have the lowest rate of effusion.
Mol. Mass of
= 80 g/mol
Mol. Mass of
= 16 g/mol
Mol. Mass of
= 17 g/mol
Mol. Mass of HBr = 81 g/mol
Mol. Mass of HCl = 36 g/mol
As, Mol. mass of HBr is the highest, so its rate of effusion will be the lowest.