Home
Class 12
CHEMISTRY
A and B are two elements which form AB(2...

A and B are two elements which form `AB_(2)` and `A_(2)B_(3)` if 0.18 mole of `AB_(2)` weights 10.6 g and 0.18 mole of `A_(2)B_(3)` weighs 17.8 g.Then

A

Atomic weight of A is 21.2

B

Atomic weight fo B is 21.2

C

Atomic weight of A is 18.8

D

Atomic weight of B is 18.8

Text Solution

AI Generated Solution

The correct Answer is:
To solve the problem, we need to determine the atomic weights of elements A and B based on the given information about the compounds they form and their respective weights. ### Step-by-Step Solution: 1. **Understand the Molar Mass Relationships**: - For the compound \( AB_2 \): - Molar mass \( M_{AB_2} = a + 2b \) - For the compound \( A_2B_3 \): - Molar mass \( M_{A_2B_3} = 2a + 3b \) 2. **Calculate Molar Mass for \( AB_2 \)**: - Given that 0.18 moles of \( AB_2 \) weighs 10.6 g, we can use the formula: \[ \text{Number of moles} = \frac{\text{Given mass}}{\text{Molar mass}} \] - Rearranging gives: \[ M_{AB_2} = \frac{10.6 \, \text{g}}{0.18 \, \text{mol}} = 58.8 \, \text{g/mol} \] - Therefore, we have the equation: \[ a + 2b = 58.8 \quad \text{(Equation 1)} \] 3. **Calculate Molar Mass for \( A_2B_3 \)**: - Similarly, for \( A_2B_3 \): - Given that 0.18 moles of \( A_2B_3 \) weighs 17.8 g: \[ M_{A_2B_3} = \frac{17.8 \, \text{g}}{0.18 \, \text{mol}} = 98.8 \, \text{g/mol} \] - Thus, we have the equation: \[ 2a + 3b = 98.8 \quad \text{(Equation 2)} \] 4. **Solve the System of Equations**: - We have the two equations: 1. \( a + 2b = 58.8 \) 2. \( 2a + 3b = 98.8 \) - To eliminate \( a \), we can multiply Equation 1 by 2: \[ 2a + 4b = 117.6 \quad \text{(Equation 3)} \] 5. **Subtract Equation 2 from Equation 3**: - Now, subtract Equation 2 from Equation 3: \[ (2a + 4b) - (2a + 3b) = 117.6 - 98.8 \] - This simplifies to: \[ b = 18.8 \] 6. **Substitute \( b \) back into Equation 1**: - Now, substitute \( b = 18.8 \) into Equation 1: \[ a + 2(18.8) = 58.8 \] - This gives: \[ a + 37.6 = 58.8 \] - Solving for \( a \): \[ a = 58.8 - 37.6 = 21.2 \] ### Final Answers: - The atomic weight of A is \( 21.2 \, \text{g/mol} \). - The atomic weight of B is \( 18.8 \, \text{g/mol} \).
Promotional Banner

Similar Questions

Explore conceptually related problems

P and Q arer two elements which form P_(2)Q_(3) and PQ_(2) . If 0.15 mole of P_(2)Q_(3) weights 15.9 g and 0.15 mole og PQ_(2) weighs 9.3 g then, what are atomic weights of P and Q ?

P and Q are two element that form P_(2) Q_(3) and PQ_(2) . If 0.15 mole of P_(2) Q_(3) weighs 15.9 g and 0.15 mole of PQ_(2) weighs 9.3 g , what are the atomic weights of P and Q ?

Suppose that A and B form the compounds B_(2)A_(3) and B_(2)A if 0.05 mole of B_(2)A_(3) weighs 9 g and 0.1 mole of B_(2)A weighs 10 g, the atomic weight of A and B respectively are

Suppose elements X and Y combine to form two compounds XY_(2) and X_(3)Y_(2) when 0.1 mole of former weigh 10 g while 0.05 mole of the latter weigh 9g . What are the atomc weights of X and Y .

Two elements P and Q combine to form two different compounds in stoichimetric ratios of 1:2 and 1:3.If 0.25 mole of 1^(st) compound weighs 16 g and 0.05 mole of 2^(nd) compound weighs 4 g, then the atomic weighs of P and Q respectively are

Two elements A and B form compounds having molecular formula AB_(2) and AB_(4) . When dissolved in 20 g of benzene, 1 g of AB_(2) lowers the freezing point by 2.3 K , whereas 1.0 g of AB_(4) lowers it by 1.3 K . The molar depression constant for benzene is 5.1 K kg mol^(-1) . Calculate the atomic mass of A and B .

Determinre the value of equilibrium constant (K_(C)) for the reaction A_(2)(g)+B_(2)(g)hArr2AB(g) if 10 moles of A_(2) ,15 moles of B_(2) and 5 moles of AB are placed in a 2 litre vessel and allowed to come to equilibrium . The final concentration of AB is 7.5 M:

Two elements A and B form compounds having formula AB_(2) and AB_(4) .When dissolved in 20g of benzene (C_(6)H_(6)) , 1g of AB_(2) lowers the freezing point by 2.3K whereas 1.0g of AB_(4) lowers it by 1.3K .The molar depression constant for benzene is 5.1Kkgmol .Calculate atomic masses of A and B .

AB,A_(2) and B_(2) are diatomic molecules. If the bond enthalpies of A_(2), AB and B_(2) are in the ratio 1:1:0.5 and the enthalpy of formation of AB from A_(2) and B_(2) is -100kJ mol^(-1) , what is the bond enthalpy of A_(2) ?

AB,A_(2) and B_(2) are diatomic molecules. If the bond enthalpies of A_(2), AB and B_(2) are in the ratio 1:1:0.5 and the enthalpy of formation of AB from A_(2) and B_(2) is -100kJ mol^(-1) , what is the bond enthalpy of A_(2) ?