Question 1

What is the yield of a reaction?

Accepted Answer

mass of product obtained from the reaction

Answer

mass of reactant used up in the reaction

Answer

mass of gases lost during a reaction

Answer

maximum mass of the product that could have been produced

Question 2

What is the theoretical yield of a reaction?

Accepted Answer

maximum mass of the product that could have been produced

Answer

mass of product obtained from the reaction

Answer

measure of how many atoms of the reactants end up as useful products

Answer

maximum mass of reactant needed to produce the optimum amount of product

Question 3

Which of these points is NOT a reason why actual yield of a reaction is always less than the theoretical yield?

Accepted Answer

a catalyst is not used

Answer

unexpected side reactions between reactants

Answer

reaction may be reversible

Answer

some of the product can be lost on separation

Question 4

What is percentage yield?

Accepted Answer

actual yield as a proportion of theoretical yield

Answer

the percentage of reactants that have formed products

Answer

the percentage sum of the theoretical yield and the actual yield

Answer

theoretical yield as a proportion of actual yield

Question 5

How is percentage yield calculated?

Accepted Answer

$\frac{ 	ext {actual yield}  }{ 	ext {theoretical yield} } 	imes 100$

Answer

$	ext {percentage yield}  	imes 	ext {theoretical yield}$

Answer

$\frac{ 	ext {actual yield}  }{ 	ext {atom economy} } 	imes 100$

Answer

$\frac{ 	ext {theoretical yield}  }{ 	ext {actual yield} } 	imes 100$

Question 6

What is atom economy?

Accepted Answer

measure of how many atoms of the reactants end up as useful products

Answer

measure of how many atoms make up all the products

Answer

measure of how many atoms of the reactants end up as waste products

Answer

measure of how many atoms make up all the reactants

Question 7

Which of these is NOT an advantage of high atom economy?

Accepted Answer

less by-product wasted

Answer

reduces costs

Answer

a higher proportion of reactants go on to form useful products

Answer

make the process more sustainable

Question 8

How is percentage atom economy calculated?

Accepted Answer

$\frac{M_r 	ext {of useful product} }{ M_r 	ext {of all products}} 	imes 100$

Answer

$\frac{M_r 	ext {of useful product} }{ theoretical yield} 	imes 100$

Answer

$\frac{M_r 	ext {of all products} }{ Percentage yield} 	imes 100$

Answer

$\frac{M_r 	ext {of all products} }{ M_r 	ext {of useful product}} 	imes 100$

Question 9

How can concentration in mol/dm$^3$ be calculated?

Accepted Answer

$\frac{	ext {moles of solute} }{	ext {volume (dm)}^3}$

Answer

$\frac{	ext {moles of solvent} }{	ext {volume (m)}^3}$

Answer

$	ext {moles of solvent} 	imes 	ext {volume (dm)}^3$

Answer

$	ext {moles of solute} 	imes 	ext {volume (dm)}^3$

Question 10

What is titration?

Accepted Answer

method used to calculate the concentration of an unknown solution

Answer

method used to calculate the volume of an unknown solution

Answer

method used to calculate the mass of an unknown solution

Answer

method used to purify an unknown solution

Question 11

What is the end-point?

Accepted Answer

the point at which the reaction is complete (when the indicator changes colour) and no substance is in excess

Answer

the point at which some product has been produced in a reaction, shown by an indicator

Answer

the point at which the products are in excess shown by a change in temperature

Answer

the point at which the total mass of reactants and products in a reaction will no longer change

Question 12

How should solution be added from the burette close to the end point?

Accepted Answer

drop by drop, swirling in between

Answer

pour it in quickly to prevent a reaction

Answer

drop by drop, keeping the reacting solution as still as possible

Answer

accurately using the base of the meniscus

Question 13

Why is a white tile used in titration?

Accepted Answer

to see the colour change better

Answer

to make it a fair test

Answer

to compare the colour of the liquid with the tile

Answer

to pour the liquid in without spillages

Question 14

What is a titre?

Accepted Answer

volume of solution added from the burette

Answer

volume of solution in the burette before the titration is started

Answer

volume of the solution in the conical flask after the end point

Answer

volume of the solution in the conical flask at the start of the titration

Question 15

What are concordant titres?

Accepted Answer

titres within $	ext  {0.1 cm}^3$ of each other

Answer

average of the titres

Answer

titres within $	ext  {0.5 cm}^3$ of each other

Answer

titres of $	ext  {2.4dm}^3$ or $	ext  { 240cm}^3$

Question 16

What volume does one mole of any gas occupy at room temperature and pressure?

Accepted Answer

$24 	ext{dm}^3$ or $24 000 	ext{cm}^3$

Answer

$2.4 	ext{dm}^3$ or $2400 	ext{cm}^3$

Answer

$0.24 	ext{dm}^3$ or$ 240 	ext{cm}^3$

Answer

$42 	ext{dm}^3$ or $42 000 	ext{cm}^3$

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