Science
Class 11
Some Basic Concepts of Chemistry - Class 11 Chemistry Chapter 1 Worksheet
Mole concept, atomic mass and the laws that started it all
This worksheet for class 11 chemistry chapter 1 covers atomic and molecular mass, the mole concept, laws of chemical combination and percentage composition through mixed practice questions.
Fill in the Blanks
Fill in the Blanks
Choose the correct word from the word bank to complete each sentence.
1.One of any substance contains the same number of particles as one mole of any other substance.
2.The number of particles present in one mole of a substance is .
3.The mass of one mole of a substance expressed in grams is called its .
4.A formula that shows the simplest whole number ratio of atoms of each element in a compound is called the formula.
5.The reactant that gets completely used up first in a chemical reaction is called the .
6.The number 6.022 x 10^23 is also known as 's number.
Quiz (MCQ)
Multiple Choice Questions
Circle the correct option for each question.
1. Which law states that a chemical compound always contains the same elements in a fixed ratio by mass, no matter how it is prepared?
2. The molar mass of water (H2O) is closest to:
3. Which law explains why carbon and oxygen can form two different compounds, CO and CO2?
4. 1 mole of any ideal gas occupies what volume at STP?
5. Which of these gives the actual number of atoms of each element in one molecule of a compound?
6. The SI unit of amount of substance is the:
True / False
True or False
Write T for true and F for false, and correct any false statement in one line.
1. According to the law of conservation of mass, matter can neither be created nor destroyed in a chemical reaction.
2. Atomic mass and molar mass always have the same numerical value with the same units.
3. Significant figures in a measurement include all certain digits plus one uncertain digit.
4. Molarity of a solution changes with temperature because volume changes with temperature.
5. The empirical formula and molecular formula of a compound are always identical.
6. Percentage composition tells us the mass percentage of each element present in a compound.
7. In a limiting reagent problem, the reagent present in the smallest amount by mass is always the limiting reagent.
Short Answer
Short Answer Questions
Answer the following in your own words, showing calculations where needed.
1. State the law of conservation of mass and give one everyday example that illustrates it.
2. Calculate the number of moles present in 4.4 g of CO2 (molar mass of CO2 = 44 g/mol). Show your working.
3. Distinguish between empirical formula and molecular formula with the help of one example.
4. A compound contains 40% carbon, 6.7% hydrogen and 53.3% oxygen by mass. If its molar mass is 180 g/mol, find its molecular formula.
These are open-ended - there's no single right answer to check.
Written by Lernizy Editorial Team
Updated 27 Aug 2026