Some Basic Concepts of Chemistry

What is matter?

Anything that occupies space and has mass

Name 2 drugs used for fighting cancer.

Cisplatin and taxol

What are the types of matter?

Pure substances and mixtures

Pure substances can be classified as:

Elements and compounds

Mixtures are of 2 types:

Homogeneous and heterogeneous

What are the laws of chemical combination?

1. Law of Conservation of Mass

2. Law of Constant Proportions

3. Law of Multiple Proportions

4. Law of Reciprocal Proportions

What is the Law of conservation of mass?

Matter cannot be created or destroyed , it can only be converted from one form to another.

What is the Law of constant proportions?

Any given compound always contains the elements combined together in the same proportion by mass.

What is the Law of Multiple Proportions?

When two elements combine with each other to form more than one compound, the masses of one element that combine with a fixed mass of the other element are in a ratio of small whole numbers.

What is the Law of Reciprocal Proportions ?

When two elements combine independently with a fixed mass of a third element, the ratio of their masses is either the same or a whole number multiple of the ratio they combine with each other.

Who stated the law of conservation of mass and in which year?

Antoine Lavoisier in 1789

Who stated the law of definite proportions and which country was he from?

Joseph Proust , french chemist

Who stated the law of multiple proportions and in which year?

Dalton in 1803.

Who stated the Law of Reciprocal Proportions?

Ritcher

What is Gay Lussac's law of gaseous volumes?

When gases combine or are produced in a chemical reaction they do so in a simple ratio by volume , provided all gases are at the same temperature and pressure.

In which year was Gay Lussac's law found?

1808

What is Avogadro's Law?

Avogadro's law states that equal volumes of all gases at the same temperature and pressure should contain equal number of molecules.

In which year did our Avogadro find Avogadro's law?

1811

What is Dalton's atomic theory?

1. Matter is composed of small particles called atoms

2. An atom cannot be created, destroyed, divided, or changed.

3. Atoms of the same element are identical.

4. Atoms of different elements have different properties

5. Atoms of different elements combine in whole number ratios to form compounds.

6. In a chemical change, atoms are rearranged, joined or separated.

How many particles are in one mole?

6.022 x 10^23

What is Avogadro's number?

6.022 x 10^23

What is relative atomic mass/atomic mass?

Atomic mass refers to the mass of one atom with respect to the mass of 1/12th of a carbon C-12 atom.

What is the value of 1 u?

1.66056 x 10^-24

State the relation between avogadro's number and one atomic mass unit.

1/NA = 1 u

What is the average atomic mass?

The weighted average of the atomic masses of the naturally occurring isotopes of an element is called average atomic mass.

What is the average atomic mass of chlorine?

35.5 u

What is the formula for average atomic mass?

(Σ Isotopic atomic mass x natural abundance)/100

What is gram atomic mass?

Gram atomic mass is the mass of one mole of an atom in gram.

What is molecular mass?

Sum of all atomic masses of elements present in a molecule is called molecular mass.

What is gram molecular mass?

Mass of one mole of a molecule in a gram.

What is formula mass/relative formula mass?

Relative mass of one formula unit of ionic solids.

What is molar mass?

The mass of one mole of a substance

One mole of every substance has the same number of particles but different masses. True or false.

True

What is STP? What is the temperature and pressure of a gas at STP?

STP is standard temperature and pressure. The temperature of a gas at STP is 273 K or 0 degree Celsius . The pressure of a gas at STP is 1 bar.

What is NTP? What is the temperature and pressure of a gas at NTP?

NTP means normal temperature and pressure. The temperature of a gas at NTP is 0°C or 273 Kelvin. Pressure of a gas at NTP is 1ATM.

What is SATP? What is the temperature and pressure of a gas at SATP?

SATP stands for standard ambient temperature and pressure. The temperature of a gas at SATP is 25°C or 298 Kelvin. The pressure of a gas at SATP is 1 bar.

What is the relation between ATM and bar?

1ATM= 1.013 bar

What is molar volume?

The volume of one mole of any gas is called molar volume.

What is the ideal gas equation?

Vm =nRT/P

What is the molar volume of a gas at NTP, STP and SATP?

The molar volume of a gas at NTP= 22.4 L, STP= 22.7 L, SATP= 24.8 L

what is vapour density of a gas?

Vapour density of a gas is its density compared with the density of hydrogen gas.

What is the relation between vapour density of a gas and the density of hydrogen?

Vapour density of a gas = density of gas/density of hydrogen.

What is the relation between vapour density and molecular mass?

Vapour density of a gas= molecular mass/2

What is the relation between vapour density of a gas and molar mass of a gas?

Vapour density of gas= molar mass of gas/2

What is the relation between number of moles and molar mass?

Number of moles= given mass/molar mass

What is the relation between number of moles and molar volume at NTP?

Number of moles= given volume at NTP/molar volume at NTP.

What is the relation between number of moles and Avogadro's number?

Number of moles= given number of molecules/Avogadro's number

How many molecules are present in one ML gas at NTP?

2.68×10 to the power 19 Molecules

What is the molar mass of a mixture of gases?

Molar mass of mixture of gases=n1m1+n2m2/n1+n2 (N= number of moles , M= molar mass)

What is the molar mass of a mixture of gases if there are two gases present?

Molar mass of mixture=m1+m2/2

What is the relation between vapour density of a mixture of gases and molar mass of a mixture of gases?

Density of a mixture of gases= molar mass of mixture/2

What is percentage composition of an element in a compound?

Percentage of an element in a compound is called percentage composition. Mass percentage of an element in a compound.= mass of element in compound/molar mass of compound x 100.

Empirical formula v/s molecular formula

Molecular formula shows exact number of different types of atoms present in a molecule whereas empirical formula shows skeletal whole number ratio of various atoms present in a compound. For example, molecular formula:C2H4O2 , EMPIRICAL FORMULA: CH2O

What is the relation between molecular formula and empirical formula?

Molecular formula= (empirical formula)x , X= molecular mass/empirical mass.

What is stoichiometry?

Stoichiometry is the calculation of masses and sometimes volumes of the reactants and products in a chemical reaction.

What is the relation between mass , volume and density?

Density= mass/volume

What is POAC?

POAC (principles of atomic conservation) states that total number of atoms of a given element in the reactants must be equal to the total number in the products — regardless of what compound they are in.

What is a limiting reagent?

The reactant that is completely used up in a chemical reaction, thus limiting amount of product that is formed is called a limiting reagent.

What is gas analysis?

Analysing composition of gas mixture by measuring, the change in volume or pressure when it reacts with other gases or reagent is called gas analysis.

What is equivalent mass?

Mass of a substance that will combine with or displace 1 g of hydrogen, 8 g of oxygen and 35 g of chlorine is called equivalent mass of that substance.

What is equivalent mass of an element?

Atomic mass/valency

What is equivalent mass of a salt?

Formula mass/total positive charge on cation or total negative charge on anion

What is equivalent mass of an ion?

Formula mass/absolute value of charge

What is equivalent mass of an acid?

Molecular mass/basicity

What is equivalent mass of a base?

Molecular mass/acidity

What is the hydride method of determining equivalent mass of a metal?

Weight of metal/weight of hydrogen x 1

What is the oxide method of determining equivalent mass of a metal?

Weight of metal/weight of oxygen x 8

What is chloride method of determining equivalent mass of a metal?

Weight of metal/weight of chlorine x 35.5

What is the formula for the volatile chloride method?

Valency= molar mass of metal *x(no of chlorine atoms in compound)/E metal + (x * 34.5)

What is the dulong and petit method?

The dulong and petit method states that the product of atomic mass and specific heat is always a constant value (6.4).

What are the exceptions to the dulong and petit method?

Exceptions are liquids, gases, beryllium, boron, carbon, and silicon.

What is the isomorphism method?

If two salts are isomorphous, and one of them has a known valency or equivalent mass, you can find the unknown value of the other compound by comparing the mass ratios in their equivalent quantities.

What does isomorphous mean?

Isomorphous compounds are substances that crystallize in the same structure and have similar chemical formulas and properties.

What is the conversion method?

Equivalent mass of unknown/mass of unknown used= equivalent, mass of known/mass of known.

What is the electrolytic method?

Mass of substance 1/mass of substance 2= equivalent mass of substance 1/equivalent mass of substance 2.

How to find mass percentage in a solution?

Mass percentage= mass of solute or solvent/total mass of solution x 100

How to find volume percentage in solution?

Volume percentage= volume of solute or solvent/total volume of solution x 100

How to find mass by volume percentage in a solution?

Mass by volume percentage= mass of solute/volume of solution x 100

How to find parts per million in a solution?

PPM= number of parts of one component/total number of parts of all components x 10 to the power 6.

What is mole fraction?

Mole fraction of a solute= nA/nA+nB

Mole fraction of a solvent = nB/nA+nB

What is molarity?

the number of moles of solute per liter of solution.

What is the formula for molarity?

M= no. of moles in solute/volume of solution in litre

What is the formula for molality?

Molality = no of moles of solute/mass of solvent in kg

What is molality ?

moles of solute/kg of solvent

What is normality?

Normality is equal to the number of equivalents of interest per liter of solution.

What is the formula for normality?

N= number of equivalent of solvent or solute/volume of solution in litre

What if formality?

No of formula units of solute per litre of solution

What is the formula for formality?

F= no of formula units of solute/volume of solution in litre

How many moles of water are present in 1 L or 1 KG?

55.5 moles

Which is more concentrated one molar aqueous solution or one molal aqueous solution?

1 molar aqueous solution

What is the relation between mass% and density?

Molarity(M)=10 x d x mass%/Molar mass of solute (M2)

Relation between molality (m) and mole fraction

m=1000(mole fraction of solute)/mole fraction of solvent * molar mass of solvent(M1)

Molarity and mole fraction relation

M=1000dx2/x1m1+x2m2

Molality and molarity relation

M=1000m/1000d - M*(M2)

Normality and molarity relation

N= n factor x M (n-factor =basicity/acidity/total electrons transferred)

Dilution formula for molarity

M1V1=M2V2

Reaction formula molarity

M1V1/n1=M2V2/n2 (n1 and n2 are stoichiometric co-efficient in a balanced equation)

Normality equation

N1V1=N2V2

Molarity of mixture if no reaction (acid+acid/base+base)

Mmix = M1V1 + M2V2/V1+V2

If V2=V1 , Mmix=M1+M2/2

Molarity of mixture is there is a reaction (acid+base)

Mmix=M1V1-M2V2/V1+V2

If V1=V2 , Mmix = M1-M2/2