The first shell can hold up to 2 electrons, the second shell can hold up to 8 (2 + 6) electrons, the third shell can hold up to 18 (2 + 6 + 10) and so on.

5 0

3 years ago

Which statement is true?

AleksandrR [38]

Exothermic reaction is where there is release of energy during a reaction

The enthalpy of exothermic reaction is negative

The relation between energy of products, reactants and enthalpy of reaction is

Enthalpy of reaction = sum of enthalpy of formation of products - sum of enthalpy of formation of reactants .

As enthalpy of reaction is negative, it means the enthalpy of products is less than the enthalpy of reactants so answer is :

In an exothermic reaction the energy of the product is less than the energy of the reactants.

7 0

3 years ago

Read 2 more answers

Calculate the total energy, in kilojoules, that is needed to turn a 46 g block

neonofarm [45]

Answer: The total energy, in kilojoules, that is needed to turn a 46 g block of ice at -25 degrees C into water vapor at 100 degrees C is 11.787 kJ.

Explanation:

Given: Mass = 46 g

Initial temperature = $-25^{o}C$

Final temperature = $100^{o}C$

Specific heat capacity of ice = 2.05 $J/g^{o}C$

Formula used to calculate the energy is as follows.

$q = m \times C \times (T_{2} - T_{1})$

where,

q = heat energy

m = mass

C = specific heat capacity

$T_{1}$ = initial temperature

$T_{2}$ = final temperature

Substitute the values into above formula as follows.

$q = m \times C \times (T_{2} - T_{1})\\= 46 g \times 2.05 J/g^{o}C \times (100 - (-25))^{o}C\\= 11787.5 J (1 J = 0.001 kJ)\\= 11.787 kJ$

Thus, we can conclude that the total energy, in kilojoules, that is needed to turn a 46 g block of ice at -25 degrees C into water vapor at 100 degrees C is 11.787 kJ.

7 0

2 years ago