Select the correct answer. which atomic property is different in each isotope of an element? a. number of protons b. number of electrons c. charge d. mass number e. atomic number

D. mass number

Explanation:

Isotopes have the same atomic number and different mass number.  

For example, the three isotopes of C are 14C, 13C and 12C.  

All the isotopes of C have the same atomic number which is 6. But 14C, 13C and 12C have mass number 14, 13 and 12 respectively. Atomic number is equal the number of protons which is also equal to the number of electrons.  Mass number is equal to the sum of the number of protons and neutrons.  14C, 13C and 12C have 8, 7, and 6 neutrons respectively.  

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