Post-UTME Past Questions - Original materials are available here - Download PDF for your school of choice + 1 year SMS alerts
WAEC offline past questions - with all answers and explanations in one app - Download for free

2023 WAEC Chemistry Theory a. In an experiment, 20.0 \(cm^3\) of a solution containing 4g/\(dm^3\) of sodium hydroxide was...

Chemistry
WAEC 2023

a. In an experiment, 20.0 \(cm^3\) of a solution containing 4g/\(dm^3\) of sodium hydroxide was neutralized by 8.0 \(cm^3\) of dilute tetraoxosulphate (VI) acid: i. Write a balanced equation for the reaction;  ii. calculate the concentration of the acid in mol/ \(dm^3\)

bi. State two postulates of the Kinetic theory of gases which real gases do not obey

ii. Explain briefly why real gases do not obey the postulates stated in 2(b)(i).

c. Consider the following compound:

     Name the compoundOpen photo

 ii. name the two structural isomers of the compound; 

 iii. state the chemical process involved in the preparation of the compound from starch,

iv. write the chemical equation for the steps involved in the process in 2(c)(ii).

v. name two enzymes involved in the process in 2(c)(iii)

d. Explain briefly the term structural isomerism.

 

WAEC Past Questions, Objective & Theory, Study 100% offline, Download app now - 24709
WAEC offline past questions - with all answers and explanations in one app - Download for free
WAEC May/June 2024 - Practice for Objective & Theory - From 1988 till date, download app now - 99995
Explanation

ai. \(H_2SO_4 + 2NaOH → Na_2SO_4 + 2H_2O\)

ii. Concentration of NaOH(\(C_n)\)
    \(C_n\) = 4/40= 0.1 mol/\(dm^3\)
    \(\frac{C_AV_A}{C_nV_n} = \frac{1}{2}\)
    \(C_A \times \frac{8}{0.1} \times 20 = \frac{1}{2}\)
    \(C_A =0.1 \times 20 \times \frac{1}{2} \times 8 = 0.125 mol /dm^3\)

bi. -The volume of a gas is negligible compared to the total volume of the container
     -There are no forces of attraction or repulsion between molecules of the gas/collision between molecules is elastic.

ii. The volume of a gas is not negligible because at high pressure the molecules occupy appreciable volume and at low temperature the
    intermolecular forces of attraction and repulsion become significant.

ci. Glucose.

ii. -Fructose
    -Galactose

iii. hydrolysis

iv. 2(\(C_6H_{10}O_5)_n + nH_2O → nC_{12}H_{12}O_{11}\)
    \(C_{12}H_{12}O_{11} + H_2O → 2C_6H_12O_6\)

v.  -maltase
     -diastase

d. It Is the existence of compounds with the same molecular formula but different structural formulae/arrangement of the atoms/linkage of the atoms.


Report an Error Ask A Question Download App
WAEC May/June 2024 - Practice for Objective & Theory - From 1988 till date, download app now - 99995
WAEC Past Questions, Objective & Theory, Study 100% offline, Download app now - 24709
Post-UTME Past Questions - Original materials are available here - Download PDF for your school of choice + 1 year SMS alerts

Contributions ({{ comment_count }})

Please wait...

{{ settings.no_comment_msg ? settings.no_comment_msg : 'There are no comments' }}

Quick Questions

Post your Contribution

Please don't post or ask to join a "Group" or "Whatsapp Group" as a comment. It will be deleted. To join or start a group, please click here

{{ quote.posted_by.display_name }}
{{ settings.form_textarea_description }}
 
WAEC offline past questions - with all answers and explanations in one app - Download for free
Post-UTME Past Questions - Original materials are available here - Download PDF for your school of choice + 1 year SMS alerts
WAEC May/June 2024 - Practice for Objective & Theory - From 1988 till date, download app now - 99995
WAEC Past Questions, Objective & Theory, Study 100% offline, Download app now - 24709
WAEC Past Questions, Objective & Theory, Study 100% offline, Download app now - 24709
Post-UTME Past Questions - Original materials are available here - Download PDF for your school of choice + 1 year SMS alerts
WAEC offline past questions - with all answers and explanations in one app - Download for free
WAEC May/June 2024 - Practice for Objective & Theory - From 1988 till date, download app now - 99995