It is defined as the mass of an element/compound/ion which combines or displaces 1 part of hydrogen or 8 parts of oxygen or 35.5 parts of chlorine by mass.

It is not always possible to apply this classic definition to determine equivalent weights of chemical entities.

Ans.

1. Pure Substance has the same composition and properties throughout Whereas Mixture is the combination of two or more pure substances where each substance retains its own identity.
2. Pure substances cannot be separated into any other kinds of matter, while a mixture is a combination of two or more pure substances.
3. A pure substance has constant physical and chemical properties, while mixtures have varying physical and chemical properties (i.e., boiling point and melting point).
4. A pure substance is pure, while a mixture is impure.
5. e.g: Pure water is a pure substance. It consist of only water molecules While e.g: Alcohol-water mixture, both co-exist together.

At STP, one mole of gas has a volume of 22.4 liters.

Given that there are 44.8 liters in this problem, which is twice as much as 22.4, there must be 2.00 moles of Carbon Dioxide CO₂ gas.

Molecular mass of Na₂CO₃ = ( 2 × 23 ) + 12 + (3 × 16) = 46 + 12 + 48 = 106 

Given mass of Na₂CO₃ = 53 g

106 g of Na₂CO₃ Contain = 1 mol

53 g of Na₂CO₃ Contain = {tex}{53\over 106} = {1\over 2}{/tex} mol  

No of atoms of Na = {tex}{1\over 2}\times 2 \times 6.022 \times 10^{23}{/tex}= {tex} 6.022 \times 10^{23}{/tex}

No of atoms of C = {tex}{1\over 2}\times 6.022 \times 10^{23}{/tex}

= {tex}3.011 \times 10^{23}{/tex}

No of atoms of O = {tex}{1\over 2}\times 3 \times 6.022 \times 10^{23}{/tex}= {tex}9.033\times 10^{23}{/tex}

Metals are malleable and ductile because they are made of hexagonal and cubic packed structures that can be moved by applying force to them. When force is applied, the atoms slide from one plane past atoms in a different plane.

Molar mass NH₃ = 14+3 = 17g/mol

4.25g = 4.25/17 = 0.25 mol

NH₃ 1mol = 6.022 {tex}\times {/tex}10²³ molecules

0.25 mol = 0.25 {tex}\times{/tex}6.022 {tex}\times {/tex}10²³

Number of molecules = 1.51 {tex}\times{/tex}10²³ 

Ans. Molecular mass if Magensium = 24.3 

So No of Atoms in 24.3 g of Magnesium = {tex}6.022 \times 10^{23}{/tex}

No of Atoms in 1 g of Magnesium =  {tex}6.022\times 10^{23}\over 24.3{/tex}
No of Atoms in 3 g of Magnesium = {tex}{6.022\times 10^{23}\over 24.3}\times 3{/tex} 

= {tex}0.743 \times 10^{23}{/tex}

Molecular Mass of ¹²C = 12 

No of Atoms in  12g of ¹²C = 6.022 × 10²³

No of Atoms in  1g of ¹²C =

{tex}{1\over 12 }\times {/tex} 6.022 × 10²³

No of Atoms in  20g of ¹²C =

{tex}{20\over 12}\times {/tex}6.022 × 10²³ = {tex}10.036 \times 10^{23}{/tex}

Thanku very much

Ans. 1 liter water =1 Kg
or 1000 ml water = 1 Kg 

Given density of Water (d) =1g/ml = 1kg/L

Mass of 1 Litre of water = Density of water * Volume   =  1 * 1 = 1 Kg = 1000g 

 Moles of water present in 1L = {tex}1000\over 18{/tex} = 55.55  

Hence Molarity of water = 55.55 M 

Doberieneir gave 3 triads

• Li Na K
• Cl Br I
• Ca Sr Ba

Solution

Concentration of glucose in blood = 0.9g/L Number of moles of glucose = {tex}{0.9\over 180 } = 0.005\space moles{/tex} 

Volume of solution = 1 litre

Hence, Molarity = {tex}Number \space of \space moles \over Volume \space of \space solution \space in\space litres{/tex} = {tex}0.005 \over 1 {/tex}=     0.005M

Ans. 1 mole of CuSO₄ provides 1 mole Of Cu.

Hence 159.5 g of CuSO₄ {tex}\to {/tex} 63.5 g of Cu

( molar mass of CuSO₄ is 159.5 and cu is 63.5)

So 100 g of CuSO₄ ll produce {tex} {63.5\times 100 \over 159.5}{/tex}

= 39.8g

Here 0.50 mol of sodium carbonate refers to the number of moles whereas 0.50 M refers to the molarity of sodium carbonate.

1. Electromagnetic waves are propagated  by  oscillating electric and  magnetic fields oscillating at right angles to each other.
2. Electromagnetic waves travel  with a constant velocity  of  3 x 10⁸ ms^-1 in vacuum.
3.  Electromagneticwaves are not deflected by electric or magnetic field.
4. Electromagneticwaves can show interference or diffraction.
5. Electromagneticwaves are transverse waves.

Ans. Green chemistry, also called sustainable chemistry, is an area of chemistry and chemical engineering focused on the designing of products and processes that minimize the use and generation of hazardous substances.