How many kilograms of water can be heated from 50°c to 75°c by co steam at 100°c? an be heated from 50°c to 75°c by condensing 1 kg of a. 10.2 kg b. 15 kg c. 21.5 kg d. 25.6 kg

Answer : The mass of water heated will be, (C) 21.5 kg

Explanation : Given,

Initial temperature =

Final temperature =

The value of latent heat of vaporization of steam at = 2260 kJ/kg

Specific heat of water =

Formula used :

or,

where,

Q = latent heat of vaporization of steam

m = mass of water

= specific heat of water

= initial temperature

= final temperature

Now put all the given value in the above formula, we get:

Therefore, the mass of water heated will be, 21.5 kg

the equation that correctly represent the reaction for formation of ammonia is

n2+ 3h2 → 2nh3 (answer d)

1 mole of nitrogen gas (n2) react with 3 moles of hydrogen gas (h2) to form 2 moles of ammonia ( nh3). this is in a process known as haber process were iron is used as a catalyst and reaction take place that a higher temperature and pressure. the process is exothermic hence energy is released.

explanation:

metals have excess of electrons whereas non-metals have deficiency of electrons. thus, in order to gain stability metals easily donate their electrons to the non-metals.

for example, electronic configuration of sodium is and electronic configuration of phosphorous is .

when a phosphorous atom and sodium atom combine together then sodium will donate is extra one electron to the phosphorous atom. as a result there will be formation of ionic bond between sodium and phosphorous.

the reaction will be as follows.

there, are three sodium sodium atoms and each of them will donate its one extra electron to phosphorous atom. thus, the sub-shell of phosphorous gets completely filled.  

thus, we can conclude that electrons are transferred from atoms of sodium to atoms of phosphorous. this transfer makes the sodium atoms donate one electron and the phosphorous atoms to gain one electron. as a result, the sodium and phosphorus atoms strongly attract each other.