Given below are a few chemical processes
A. Rusting of iron
B. Burning of a candle
C. Respiration
D. Photosynthesis'
Which two of these represent slow combustion?
D and A
A and C
B and C
B and D
B.
A and C
The reaction of an element or compound with an excess of oxygen is called combustion and the combustion process which takes a long time is called slow combustion.
(A)Rusting of iron involves the conversion of iron (Fe) into Fe2O3.xH2O (rust) and takes a longer time, so it is a slow combustion process.
(B)Burning of a candle does not take a longer time, so it is not a slow combustion process.
(C) Respiration involves the breaking down of glucose into CO2 and H2O by O2 and takes a longer time, so it is a slow combustion process.
(D) Photosynthesis, on the other hand, involves the reaction of carbon dioxide and water to give carbohydrate, so it is not a combustion process.
When CNG or LPG undergoes complete combustion, the products formed are
CO2 and H2O
CO2, SO2, and H2O
CO2 only
CO2, CO, and H2O
Assessment in Science should focus more on testing the ability of students to
answer open-ended questions
be sufficiently equipped for higher learning
state the facts and principles of Science correctly
apply the understanding of concepts to unfamiliar situations in everyday life
The process of converting sugars into alcohols is known as
pasteurisation
sterilisation
homogenisation
fermentation
One of the main limitations of the Project method of teaching Science is that
knowledge is not acquired in a sequential manner
integration of concept in various subjects can be achieved
the students have to perform excessive mental and physical work
it is a psychological method
Summative Assessment in Science should mainly focus on
assessing observation skills
diagnosing the areas of learning difficulties of students
testing of mainly the practical skills
testing important theoretical concepts
The dietary fibres are
made up of collagen fibres
made up of proteins
also called roughage
made up of cellulose and proteins
If the frequency of vibrations of a body is decreased and its amplitude is increased, then
pitch increases but loudness decreases
pitch decreases but loudness increases
both pitch and loudness of sound produced will increase.
both pitch and loudness of sound produced will decrease