Balbharati solutions for Chemistry [English] 11 Standard chapter 1 - Some Basic Concepts of Chemistry [Latest edition]

A sample of pure water, whatever the source always contains ______ by mass of oxygen and 11.1% by mass of hydrogen.

Choose the correct option.

Which of the following compounds can not demonstrate the law of multiple proportions?

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Which of the following temperature will read the same value on celsius and Fahrenheit scales?

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SI unit of the quantity electric current is __________

In the reaction \[\ce{N2 + 3H2->2NH3}\], the ratio by volume of \[\ce{N2 , H2}\] and \[\ce{NH3}\] is 1 : 3 : 2 This illustrates the law of ______.

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Which of the following has maximum number of molecules?

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How many g of H₂O are present in 0.25 mol of it?

The number of molecules in 22.4 cm³ of nitrogen gas at STP is ______.

Which of the following has the largest number of atoms?

State and explain Avogadro's law.

Point out the difference between 12 g of carbon and 12 u of carbon.

How many grams does an atom of hydrogen weigh?

Calculate the molecular mass of the following in u.

NH₃

Calculate the molecular mass of the following in u.

CH₃COOH

Calculate the molecular mass of the following in u.

C₂H₅OH

How many particles are present in 1 mole of a substance?

What is the SI unit of the amount of a substance?

What is meant by the molar volume of a gas?

State and explain the law of conservation of mass.

State the law of multiple proportions.

Give one example of a homogeneous mixture.

Give one example of a heterogeneous mixture.

Give one example of an element.

Give one example of a compound.

What is the ratio of molecules in 1 mole of NH₃ and 1 mole of HNO₃?

Solve problem:

Calculate the number of moles of hydrogen in 0.448 litre of hydrogen gas at STP.

Solve problem:

The mass of an atom of hydrogen is 1.008 u. What is the mass of 18 atoms of hydrogen?

Solve problem:

Calculate the number of an atom of the following (Given: Atomic mass of I = 127 u).

254 u of iodine (I)

Solve problem:

Calculate the number of an atom of the following (Given: Atomic mass of I = 127 u).

254 g of iodine (I)

Solve problem:

A student used a carbon pencil to write his homework. The mass of this was found to be 5 mg. With the help of this calculate the number of moles of carbon in his homework writing.

Solve problem:

A student used a carbon pencil to write his homework. The mass of this was found to be 5 mg. With the help of this calculate The number of carbon atoms in 12 mg of his homework writing

Solve problem:

Arjun purchased 250 g of glucose (C₆H₁₂O₆) for Rs 40. Find the cost of glucose per mole.

Solve problem:

The natural isotopic abundance of ¹⁰B is 19.60% and ¹¹B is 80.40 %. The exact isotopic masses are 10.13 and 11.009 respectively. Calculate the average atomic mass of boron

Solve problem:

Convert the following degree Celsius temperature to degree Fahrenheit.

40 °C

Convert the following degree Celsius temperature to degree Fahrenheit.

30°C

Solve problem:

Calculate the number of moles and molecules of acetic acid present in 22 g of it.

Solve problem:

24 g of carbon reacts with some oxygen to make 88 grams of carbon dioxide. Find out how much oxygen must have been used.

Solve problem:

Calculate the number of atoms of the following. (Average atomic mass : N = 14 u, S = 32 u)

0.4 mole of nitrogen

Solve problem:

Calculate the number of atoms of the following. (Average atomic mass : N = 14 u, S = 32 u)

1.6 g of sulfur

Solve problem:

2.0 g of a metal burnt in oxygen gave 3.2 g of its oxide. 1.42 g of the same metal heated in steam gave 2.27 of its oxide. Which law is verified by these data?

In two moles of acetaldehyde \[\ce{CH3CHO}\] calculate the number of moles of carbon.

Solve problem:

In two moles of acetaldehyde (CH₃CHO) calculate the number of moles of hydrogen

Solve problem:

In two moles of acetaldehyde (CH₃CHO) calculate the number of moles of oxygen

Solve problem:

In two moles of acetaldehyde (CH₃CHO) calculate the number of molecules of acetaldehyde

Solve problem:

Calculate the number of moles of magnesium oxide, MgO in

1. 80 g, and
2. 10 g of the compound.

(Average atomic masses of Mg = 24 and O = 16)

Solve problem:

What is volume of carbon dioxide, CO₂ occupying by 5 moles of CO₂ gas measured at STP?

Solve problem:

What is volume of carbon dioxide, CO₂ occupying by 0.5 moles of CO₂ gas measured at STP?

Solve problem:

Calculate the mass of potassium chlorate required to liberate 6.72 dm³ of oxygen at STP. Molar mass of KClO₃ is 122.5 g mol^-1.

Calculate the number of atoms of hydrogen present in 5.6 g of urea, \[\ce{(NH2)2CO}\]. Also calculate the number of atoms of N, C, and O.

Solve problem:

Calculate the mass of sulfur dioxide produced by burning 16 g of sulfur in excess of oxygen in the contact process. (Average atomic mass : S = 32 u, O = 16 u)

Explain the need of the term average atomic mass.

Explain molar mass.

Explain the mole concept.

Explain formula mass with an example.

Explain the molar volume of gas.

Explain types of matter (on the basis of chemical composition).