Elements and the Periodic Table Date
Class
C
.
Section 4.1 Quiz
If the statement is true write true. If the statement is false, change the underlined
word or words to make the statement true.
1. Atomic theory grew as a series of scientific models.
2. Ernest Rutherford thought that atoms were like smooth,
hard balls that could not be broken into smaller pieces.
3. The positively charged particles in an atom's nucleus are
called electrons.
4. Democritus suggested that electrons move in specific
orbits around the nucleus of an atom.
5. The modern model of an atom describes the atom as
mostly empty space.

true true true true true true true

1.true

2.false

3.true

4.true

5.false

Explantation:

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