Answer : Option A) Multiply the ratio of the actual mass of the compound to the empirical formula mass by the subscripts of the empirical formula.
Explanation : To find molecular formula for a compound one needs to follow the below steps using the emphirical formula of that compound.
Step 1) Calculate the empirical formula mass of that compound
Step 2) Take the ratio of gram molecular mass by the empirical formula mass that was obtained in step 1.
Step 3) Multiply each of the subscripts within the empirical formula by the number that is calculated in step 2.
By following these easy steps one can find the molecular formula.
The step that would help a student finds the molecular formula of a compound from the empirical formula is by ‘Multiply the ratio of the actual mass of the compound to the empirical formula mass by the subscripts of the empirical formula.’
Given:
KOH used to make 1.6 liters of 15% by mass solution with water
Required:
grams of KOH
solution:
the density of KOH is equal to 2.12 kg/L
multiply the known volume of KOH to the density and the percentage of KOH in water
mass of KOH = 1.6 L (2.12 kg/L)(0.15) = 22.61 grams of KOH
b. more neutrons than electrons.
c. an equal number of neutrons and protons.
d. an equal number of protons and electrons.
Answer:
2.53 grams of hydrogen gas will be produced and 12.2 many grams of the excess reactant i.e. calcium will be left over.
Explanation:
Moles of calcium =
Moles of HCl =
According to reaction, 2 moles of HCl reacts with 1 mole of calcium :
Then 2.53 moles of HCl will recat with :
of calcium.
As we can see moles of calcium are in excessive amount. Hence calcium is an excessive reagent.
Moles of calcium left unreacted =1.57 mol - 1.265 mol =0.305 mol
Mass calcium left unreacted = 0.305 mol × 40 g/mol =12.2 g
Since, calcium is an excessive reagent HCl is limiting reagent and the amount of hydrogen gas produced will depend on HCl .
According to reaction, 2 moles of HCl gives 1 mole of hydrogen gas.
Then 2.53 moles of HCl will give:
of hydrogen gas.
Mass of 1.265 mol of hydrogen gas = 1.265 mol × 2 g/mol = 2.53 g
2.53 grams of hydrogen gas will be produced and 12.2 many grams of the excess reactant i.e. calcium will be left over.
Answer:
2.55 g of hydrogen
12.17 g calcium.
to nearest hundredth.
Explanation:
The balanced equation is:
Ca + 2HCl ---> CaCl2 + H2
Using the atomic masses
40.078 g Ca react with 72.916 g of HCl to give 2.016 g HCl
The ratio of Ca to HCl in the above is 1 to 1.81935
so 62.8 g Ca reacts with 62.8 * 1.81935 = 114.245 g HCl
so there is excess of Ca in the given weights.
Therefore the mass of Hydrogen produced
= (2.016 / 72.916) * 92.3
= 2.552 g of hydrogen gas.
The mass of calcium required to produce 2.552 g of hydrogen is:
(2.552 / 2.016) * 40.078
= 50.73 g
So the excess of calcium is 62.8 - 50.73
= 12.17 g.
Answer:
A branch of science
Explanation:
CHemistry is the investigation and studying substances and their reaction with other elements
Answer:
chemistry :-
A branch of science in which we. . study about chemical
in the chemistry we studied about. elements and compounds and their
composition and reaction