1. Write balanced chemical equation for the reaction that takes place during
respiration. Identify the type of combination reaction that takes place
during this process. Give one more example of this type of reaction
2. Which of the following substances in water will not show acidic properties
and why? Sugar, Alcohol, Acetic Acid, Urea, Nitric Acid, and Carbon dioxide.
3. Name the following:
(i) the 2 carbon molecule that is formed due to the breakdown of glucose
during respiration.
(ii) the nitrogenous waste that is removed from the blood in our kidneys
(iii) how to unicellular organisms generally remove waste?
(iv) rings of cartilage are present in trachea.
4. How would you join three resistors, each of resistance 9 ohm so that the
equivalent resistance of the combination is (i) 13.5ohm (ii) 6 ohm?
5. a stationary charge is present in a magnetic field. Will it experience a force?
Give reason to justify your answer.
Answers
Answer:
1. Balanced reaction ( not real reaction ) that takes place during respiration -
C6H12O6 + O2 ------> 6CO2 + 6H2O + Energy
It is exothermic reaction because a large amount of heat is released.
Example : Decomposition of vegetable matter into compost.
2. The substances that will show Acidic properties are - Sugar, Alcohol, Acetic Acid, Urea, Nitric Acid and Carbon Dioxide.
Sugar and artificial sweeteners are highly acidic foods, which is one of the reasons the consumption of sweets has recently been linked to so many health ailments.
Alcohols are weak acids. The most acidic simple alcohols (methanol and ethanol) are about as acidic as water, and most other alcohols are somewhat less acidic.
Acetic Acid is a weak acid used in the production of vinegar.
Urea contains Nitric Acid which is a strong acid.
CO2 gas is a Lewis acid(electron acceptor) in that it accepts electrons from Lewis bases (electron donors). It is acidic in nature. On dissolving in water it produces H2CO3 (carbonic acid).
3. i) The three carbon molecule that is formed due to break-down of glucose during respiration.
(ii)The nitrogenous waste that is removed from the blood in kidneys is Urea.
(iii) The unicellular organism remove waste directly through cell membrane by process of simple diffusion.
(iv) Tracheal rings
4. (i) equivalent resistance = 13.5 Ω
Join two resistors in parallel and one in series as shown in 1st figure
We know, in parallel ,
1/R' = 1/R₁ + 1/R₂
Here , R₁ = R₂ = R₃ = 9Ω
Now, 1/R' = 1/9Ω + 1/9Ω ⇒ R' = 9/2Ω = 4.5 Ω
So, equivalent resistance , Req = R' + R₃ [ ∵ R' and R₃ in series ]
∴ Req = 4.5Ω + 9Ω = 13.5Ω
(ii) Equivalent resistance = 6Ω
two resistors are in series which is parallel with 3rd resistor as shown in 2nd figure .
now, R' = R₁ + R₂ = 9Ω + 9Ω = 18Ω [ R₁ and R₂ are in series ]
now, equivalent resistance, Req = R'R₃/(R' + R₃) [ R' and R₃ are in parallel ]
∴ Req = 18 × 9/(18 + 9) = 18 × 9/27 = 6Ω
5. No, a magnetic field exerts a force only on moving charges. If the first finger points in the direction of magnetic field and the middle finger in the direction of current, then the thumb will point in the direction of motion or the force acting on the conductor.