Answer : The mass of a sample of water is, 888.89 grams
Explanation :
Latent heat of vaporization : It is defined as the amount of heat energy released or absorbed when the liquid converted to vapor at atmospheric pressure at its boiling point.
Formula used :

where,
q = heat = 2000 kJ =
(1 kJ = 1000 J)
L = latent heat of vaporization of water = 
m = mass of sample of water = ?
Now put all the given values in the above formula, we get:

(1 kg = 1000 g)
Therefore, the mass of a sample of water is, 888.89 grams
Answer:
2019 light bulbs
Explanation:
So the electrical energy consumed by each 59-W light bulb within 7 hours is the product of the power and time duration
E = Pt = 59 * 7 = 413 Wh or 0.413 kWh
If each light bulb consumes 0.413 kWh, then the total number of light bulbs needed to consume 834 kWh would be
834 / 0.413 = 2019 light bulbs
Answer:
a) increases
Explanation:
The increase in temperature causes the particles to move much faster. This in turn effects the collision rate of the particle which causes the chemical reaction. Thus the rate of chemical reaction increases.
So, we conclude that the rate of a chemical reaction is directly related to temperature. With increase in temperature there is an increase in the reaction rate and vice versa.
Answer:
b) the potential difference across each is the same.
Explanation:
When resistors are connected in parallel with each other
then the terminals of all the resistors will connected across the terminals of the battery
So we know the potential difference of the battery is same across all the resistors
So we can say that the equivalent resistance of all the resistance is

so its not the mean of all resistors
also we know that the resistance are all different so power across each resistance is different given as

also current in each resistance is also different and given by

so correct answer will be
b) the potential difference across each is the same.