Chemical calculation questions uses many relationships of different parameters to solve or find unknown values. Questions are different from one to one. In school level, chemical equations, gas equations, moles, mass, concentration and more parameters are used.
Questions are prepared by following lessons and those lessons are combined to prepare these problems. Answers, explanations and necessary theories are provides for every questions.
There is a pure NaOH bottle which contains NaOH as crystals. Some NaOH crystals are separated from the bottle and measured the mass using a balance. Then mass of separated NaOH was 2.2 g. How much NaOH (in moles) is separated? ( Na=23 , O=16 , H=1 )
Answer: 0.055 mol
You ara said to separate 0.1 mol of potassium dichromate. What is the required mass of potassium dichromate? ( K=39 , Cr=52 , O=16 )
Answer: 29.4 g
There is a white solid which contains calcium oxide as the main ingredient. Rest of others are impurities. It was required to calculate mass percentage of calcium oxide in this solid. So, as the first step. mass of solid was measured and it was 11.1 g. When mass percentage of calcium oxide was calculated by a chemical method, it was 75.68 %. So how much (mol) calcium oxide was there?
Answer: 0.15 mol
A mixture of 1kg of CaO and MgO should be prepared in the laboratory. Moles ratio between CaO and MgO is two to one. Aqueous solutions of CaCl2, MgCl2 and solid Na2CO3 are given to prepare CaO and MgO mixture. Also laboratory instruments can be used in necessaries such as heating, mixing, filtering and more. Calculate required Na2CO3 mass and volume of each CaCl2 and MgCl2 aqueous solutions.
Following data may be useful to solve this question.
concentration of CaCl2 solution = 9.87 mol dm-3
concentration of MgCl2 solution = 9.77 mol dm-3
Relative atomic masses : O=16 , C=12, Mg=24 , Cl=35.5 , Ca=40
You need to prepare 250cm3 solution of 0.1 mol dm-3 NaOH. You are provided a concentrated 10.1 mol dm-3 NaOH solution. What is the required volume of concentrated NaOH to prepare that diluted NaOH solution?
From 2 mol dm-3 HCl 250 cm3 solution, You have to prepare 0.1 mol dm-3 HCl 100 cm3 solution. How to you prepare this dilute solution from given concentrated solution.
Nitric(iii) acid (nitrous acid / HNO2) is stable when nitrous acid solution is dilute. Nitrous acid is prepared as follow.
4.2 g of hydrocarbon is burnt in excess oxygen gas stream and cooled to room temperature after the completion of the reaction. In the end of the reaction, it is found that amount of produced carbon dioxide gas is 0.08 mol. Find the molecular formula of the hydrocarbon.
When excess ammonia reacts with chlorine gas, ammonium chloride and nitrogen gas are given as products. To produce 1 mol of nitrogen gas, how much amount of ammonia and chlorine gases are required?
Calculate required amount of hydrogen peroxide (H2O2) moles to react with lead sulfide.
PbS + H2O2 → PbSO4 + H2O
To neutralize 0.01 mol dm-3 NaOH 25 cm3 solution, you are going to use 0.04 mol dm-3 Ba(OH)2 solution. What is the required volume of Ba(OH)2 solution.