Cement is a mixture of so many compounds roasted in rotary kiln. Which substances has greater percentage ?
Correct answer: A. Lime (CaO)
- A. Lime (CaO)
- B. Silica (SiO2)
- C. Alumina (Al2O3)
- D. Magnesia (MgO)
Explanation
Calcium oxide is the major oxide in ordinary Portland cement because limestone is the largest part of the raw mix and decomposes to CaO on heating. Silica, alumina and magnesia are present in smaller percentages. Students may choose silica because it forms important silicate compounds, but importance of a compound is not the same as having the greatest percentage.
Report an error
The more specific you are, the faster it gets fixed. A source beats an opinion.
Prefer email? [email protected]
About Exothermic and Endothermic Reactions
Exothermic reactions release heat to the surroundings and have negative enthalpy change, while endothermic reactions absorb heat and have positive enthalpy change. The topic uses energy profiles to identify reactants, products and activation energy, and includes bond energy, enthalpy diagrams, calorimetry and Hess's law for calculating overall heat changes.
Practise Thermochemistry and Energetics of Chemical Reactions
728 free Thermochemistry and Energetics of Chemical Reactions MCQs from Chemistry, each with the correct answer and an explanation. Unlimited attempts, no account needed.
Discussion
Stuck on an option, or know a faster way to get there? Ask or explain it here.
No comments yet. Be the first to explain this one.
Exams that ask Chemistry questions like this
Chemistry is on 14 papers prepared for on TestUstad, and all of them draw the same bank, so this question is worth knowing for every one of them.
More Exothermic and Endothermic Reactions questions
Which sequence of steps is correct for the manufacture of cement ?
The composition of mixture of clay and lime stone in the raw for cement material is __________________?
The important function of burning zone in the rotary kilm is __________________?
Cement is a mixture of________________?
When enthalpy of reactants is higher than product then reaction will be_________________?
Reaction in which heat evolves is called ____________________?