Answer: 0.028 grams
Explanation:
Depression in freezing point :
Formula used for lowering in freezing point is,

or,

where,
= change in freezing point
= freezing point constant (for benzene} =
m = molality
Putting in the values we get:


0.028 grams of DDT (solute) must be dissolved in 209.0 grams of benzene to reduce the freezing point by 0.400°C.
Answer:
This is because, Kelvins and Celcius degrees both agree at fixed points i.e; the lower fixed point and upper
Natural abundance of oxygen I think
The moving car experiences unbalanced forces when applying brakes; when a car is slowing as it reaches a stop light.
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Explanation:
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When the car driver applies brakes to a car in order to stop, an unbalanced force is applied to the car. The speed of car gradually reduces and there’s a decrease in acceleration; a net force acts on it.
Options A and D has a box and a rocket always in a rest position. A car with cruise control is an adaptable speed setting for a vehicle which helps it to maintain a fairly constant speed. Constant velocity gives zero acceleration and hence no considerable unbalanced forces appear.