<span>In chemistry, a catalyst can speed up the reaction (or make it initiate easier) by altering the activation energy, lowering it enough to allow the reactants to react more easily. Some negative catalysts or inhibitors can do the same by increasing the activation energy.
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Answer:
The volume of air at where the pressure and temperature are 52 kPa, -5.0 ºC is
.
Explanation:
The combined gas equation is,

where,
= initial pressure of gas = 104 kPa
= final pressure of gas = 52 kPa
= initial volume of gas = 
= final volume of gas = ?
= initial temperature of gas = 
= final temperature of gas = 
Now put all the given values in the above equation, we get:


The volume of air at where the pressure and temperature are 52 kPa, -5.0 ºC is
.
Answer:
A) Sample B has more calcium carbonate molecules
Explanation:
M = Molar mass of calcium carbonate = 100.0869 g/mol
= Avogadro's number = 
For the 4.12 g sample
Moles of a substance is given by

Number of molecules is given by

For the 19.37 g sample

Number of molecules is given by


So, sample B has more calcium carbonate molecules.
The ratio of the elements of carbon, oxygen, calcium atoms, ions, has to be same in both the samples otherwise the samples cannot be considered as calcium carbonate. Same is applicable for impurities. If there are impurites then the sample cannot be considered as calcium carbonate.
Each of the Nitrogen atoms has 2 non bonded valence electrons, meaning that there are 4 pairs total.