Question

Balance the chemical equation below using the smallest possible whole number stoichiometric coefficients.

Answer 1

\[CH _{3}CH _{2}CH _{3}(g)+O _{2}(g) rightarrowCO _{2}(g)+H ^{2}O(g)\]

Answer 2

balance the carbons first,

how many carbon atoms on the lefthand side of the equation ?

Answer 3

Either 3 or 8 not sure if the little numbers count for the carbon or just for the hydrogen.

Answer 4

its three, the subscripts belong to the atom directly to the left to them only

Answer 5

how many carbons on the right hand side?

Answer 6

1

Answer 7

correct,


now we want to balance the carbons,

what stoichiometric coefficients (a, b) will balance the carbons in the equation?

\[a\times3=b\times1\]

Answer 8

Umm? 3? I am unsure of what stoichiometric means and it is throwing me off.

Answer 9

\[{\text{CH} _{3}\text{CH} _{2}\text{CH}_{3}}_{(g)}+{\text O _{2}}_{(g)} \Longrightarrow {\text {CO }_{2}}_{(g)}+{\text H ^{2}\text O}_{(g)}\]


if a = 1, and b=3, then the equation will balance
so we write

\[{\text{CH} _{3}\text{CH} _{2}\text{CH}_{3}}_{(g)}+{\text O _{2}}_{(g)} \Longrightarrow \color{brown}3{\text {CO }_{2}}_{(g)}+{\text H ^{2}\text O}_{(g)}\]

which makes the carbons balanced

Answer 10

see how there are 3 carbon on each side now?

Answer 11

now for the hydrogen

how many hydrogens are on each side?

Answer 12

8 on the left 2 on the right. so we need to add 6 to the right side?

Answer 13

yeah, but we can't add, we have to multiply,

what do we multiply 2 by to get 8?

Answer 14

4

Answer 15

yeps so

\[{\text{CH} _{3}\text{CH} _{2}\text{CH}_{3}}_{(g)}+{\text O _{2}}_{(g)} \Longrightarrow \color{brown}3{\text {CO }_{2}}_{(g)}+\color{brown}4{\text H _{2}\text O}_{(g)}\]

now there are 8 hydrogens on each side

Answer 16

making sense so far?

Answer 17

H\[^{2*4}\]

Answer 18

all that is left is to balance the oxygens

Answer 19

\[4H _{2}2O(g)\]

Answer 20

on the right side

Answer 21

pardon?

Answer 22

how many oxygens can you count on each side?

Answer 23

2 on the left 3 on the right

Answer 24

yeah there are two oxygens on the left,

but there are more than 3 on the right

Answer 25

for each CO_2 there are 2 oxygens

for 3 CO_2 there are 3*2 oxygen


for each H_2O there is one oxygen

for 4 H_2O there are 4* 1 oxygens


add them all up 3*2 + 4*1 =

Answer 26

so there are 11?

Answer 27

nope

Answer 28

Oh 10! Duh, sorry I am having mommy brain today!

Answer 29

yeah so 2 oxygens on the left,
and 10 on the right

Answer 30

what stoichiometric coefficients can we multiply the oxygen gas on the left by, to get 10 oxygen on the left

Answer 31

5

Answer 32

So you have\[{\text{CH} _{3}\text{CH} _{2}\text{CH}_{3}}_{(g)}+\color{brown}5{\text O _{2}}_{(g)} \Longrightarrow \color{brown}3{\text {CO }_{2}}_{(g)}+\color{brown}4{\text H _{2}\text O}_{(g)}\]

check that all the element are balanced

how many carbons, how many hydrogen , and how many oxygens are on both sides of the equation?

Answer 33

10 oxygen, 3 carbon, 8 hydrogen

Answer 34

its balanced! good work

Answer 35

the 1, 5, 3, and 4 are the stoichiometric coefficients

Answer 36

so all I do is insert the red numbers and I have the answer? 5 on the left 3 and 4 on the right?

Answer 37

yeah, its done now

Answer 38

Awesome! Wow, hoping the rest are not as hard!

Answer 39

if you had scaled-up coefficients like

\[\color{blue}2{\text{CH} _{3}\text{CH} _{2}\text{CH}_{3}}_{(g)}+\color{blue}{10}{\text O _{2}}_{(g)} \Longrightarrow \color{blue}6{\text {CO }_{2}}_{(g)}+\color{blue}8{\text H _{2}\text O}_{(g)}\]
it would still balance, but the coefficients wouldn't be the smallest possible whole numbers .