Which two subatomic particles have the same mass but do not have the same charge? A. None of these
B. Neutrons and quarks
C. Electrons and neutrons
D. Protons and neutrons

d

Explanation:

b/ce The strong force effects produce a mass that is essentially independent of the kinds of quarks involved, so this mass contribution will be the same for the proton and neutron.

"record the time to complete a chemical reaction" would most likely be part of a lab procedure.

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