The double replacement reaction between calcium nitrate (Ca(NO3)2) and potassium oxide (K2O ) is shown below: Ca(NO3) 2 + K2 O → CaO + KNO3
How many grams of potassium oxide would be needed to produce 5.00 g of potassium nitrate (KNO3) ?

Mass = 2.355 g

Explanation:

Given data:

Mass of K₂O needed = ?

Mass of KNO₃ produced = 5.00 g

Solution:

Chemical equation:

K₂O + Ca(NO₃)₂     →   CaO +  2KNO₃

Number of moles of KNO₃:

Number of moles = mass/molar mass

Number of moles = 5.00 g/ 101.1 g/mol

Number of moles = 0.05 mol

now we will compare the moles of KNO₃ and K₂O.

                KNO₃           :             K₂O

                   2                :               1

                  0.05           :           1/2×0.05 = 0.025 mol

Mass of potassium oxide needed in gram:

Mass =  number of moles × molar mass

Mass = 0.025 mol × 94.2 g/mol

Mass = 2.355 g

the correct option is c.

isotopes refers to different forms of the same element with the same atomic number but different mass number as a result of difference in their neutron numbers. isotopes have different relative atomic mass but share the same chemical properties.

the potential energy of the reactants is 200j.

from the energy diagram, the energy of the product formed is 350j; this means that, this reaction is an endothermic reaction, because it absorbs energy from its environment.