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Competency Qns

The document contains a set of competency-based questions related to chemical reactions and equations for students at The Emirates National School-Sharjah. It includes five questions that require students to analyze scenarios involving baking ingredients, chemical reactions in cooking, gas evolution, silver tarnishing, and metal reactivity. Each question is assigned a specific mark value, totaling 10 marks for the exercise.

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Prasanthni Purushothaman
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40 views1 page

Competency Qns

The document contains a set of competency-based questions related to chemical reactions and equations for students at The Emirates National School-Sharjah. It includes five questions that require students to analyze scenarios involving baking ingredients, chemical reactions in cooking, gas evolution, silver tarnishing, and metal reactivity. Each question is assigned a specific mark value, totaling 10 marks for the exercise.

Uploaded by

Prasanthni Purushothaman
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as PDF, TXT or read online on Scribd
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THE EMIRATES NATIONAL SCHOOL-SHARJAH

COMPETENCY BASED QUESTIONS


CHEMICAL REACTIONS AND EQUATIONS
DATE: TIME: 20MIN
Q QUESTIONS MARK
NO S
1. Trupti mixed one teaspoon of baking soda in 500 g of cake mixture. She kept the 2
mixture aside for 5 minutes. Geeta mixed one teaspoon of baking powder in 500 g of
the same cake mixture. She also kept the mixture aside for 5 minutes. She then
baked the two cakes together in the same oven. Whose cake is likely to rise higher?
Justify your answer.
2. While cooking in an aluminum vessel, Sudeshna burned some food till all that 2
was left was a completely charred and black residue. She just left the
blackened vessel heating on the stove. After an hour she found that the vessel
was completely clean, with no trace of any blackness. (a) Write a chemical
equation to explain what happened to the charred, black residue that made it
disappear. (b) Name the type of reaction referred to in (a).
3. A white powder is added to dilute hydrochloric acid. A colorless gas is evolved, and a 2
colorless solution is formed. Identify the white powder and write a balanced
chemical equation.
4. Silver articles become black after some time when exposed to air. However, when 2
rubbed, they regain their shine.
a) Name the chemical phenomenon involved in the observation.
b) Write the chemical equation for the reaction responsible for the black coating.

5. A metal X is found to react with dilute hydrochloric acid to liberate hydrogen 2


gas but does not react with cold water. Another metal Y does not react with
dilute acid.
a) Arrange X, Y, and hydrogen in the reactivity series.
b) Which type of chemical reaction occurs between metal X and hydrochloric
acid?

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