Asample of water is heated from room temperature to just below the boiling point. the overall change in temperature is 72â°c. express this temperature change in kelvins. (a) 345 k (b) 72k (c) 0k (d) 201 k (e)273k

Answer : The correct option is, (a) 345 K

Explanation :

The conversion used for the temperature from degree Celsius to Kelvin is:

where,

= temperature in Kelvin

= temperature in centigrade

As we are given the temperature in degree Celsius is, 72

Now we have to determine the temperature in Kelvin.

Therefore, the temperature in Kelvin is, 345 K

Option (a) is the correct answer.

Explanation:

It is known that when temperature is given in degree celsius and we want it to convert into kelvin then we need to add 273 into the given degree celsius.

For example, given temperature is .

Now, to convert it into degree celsius we need to add 273 into it as follows.

   Temperature in Kelvin = (72 + 273) K

                                         = 345 K

Thus, we can conclude that given temperature in Kelvin is 345 K.

as given the equation is

2al + 6 hcl > 2 alcl3 + 3 h2(g)

as per equation two moles of aluminum reacts with six moles of hcl to give two moles of alcl3 and three moles of hydrogen gas

given: three moles of al are present and 7 moles of hcl

for three moles of aluminum nine moles of hcl will be required

however as 7 moles of hcl are present so the limiting reagent is hcl

hcl is going to decide the number of moles of product formed

when six moles of hcl are present = 3 moles of h2 are formed

when one mole of hcl is present == 3/6 mole sof h2 will be formed

when 7 moles of hcl are present = 3 x 7/ 6 moles of h2 will be formed = 3.5 moles of h2