Joan writes four numbers on the board in standard form, and then she writes their scientific notation. The table below shows her numbers.
Row
1
Joan's Numbers
Number in standard form
7,100
-0.000041
-39.000
120.000
2.
Number in scientific notation
7.1 x 10
4.1 x 10-5
-3.9 x 104
1.2 x 106
3
4
In which row of the table did Joan make a mistake in writing the scientific notation?
1
2
3
4

jdjxnbfb

explanation:

jjfnc fdnxnxx

im not exactly sure but i think its b!

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