Question

A solution of salt and water contains 75 grams of water per 150 milliliters of the solution. If 1 mole of water weighs 16 grams, _____ moles of water would be present in 30 milliliters of the solution. [Round off your answer to two decimal places]

Answer 1

i got .94

Answer 2

\[\frac{ 75 \cancel{\text{ g H}_2 \text{O}} }{ 150 \cancel{\text{ ml sol'n} }}\cdot \frac{ 1 \text{ mol of H}_2 \text{O}}{ 16 \cancel{\text{ g H}_2 \text{O} }}\cdot 30 \cancel{\text{ ml sol'n}}\]

Answer 3

=30/32 = .9375 mol = .94 mol.

good job!

Answer 4

can you help with one more

Answer 5

Which table best represents the steps to solve the equation 8 + x over 3 = 4?

Step Justification
Step 1: x over 3 = 4 + 8 The same number +8 can be added to both sides of the equation
Step 2: x over 3 = 12 Adding 8 and 4 on the right hand side
Step 3: x = 12 • 3 The same number 3 can be multiplied on both sides of the equation
Step 4: x = 36 Multiplying 12 and 3 on the right hand side

Step Justification
Step 1: x over 3 = 4 - 8 The same number -8 can be added to both sides of the equation
Step 2: x over 3 = -4 Adding -8 and 4 on the right hand side
Step 3: x = -4 • 3 The same number 3 can be multiplied on both sides of the equation
Step 4: x = -12 Multiplying -4 and 3 on the right hand side

Step Justification
Step 1: x over 3 = 4 - 8 The same number - 8 can be added to both sides of the equation
Step 2: x over 3 = -4 Adding 4 and -8 on the right hand side
tep 3: x = - 4 - 3 The same number 3 can be subtracted from both sides of the equation
Step 4: x = -7 Simplifying -4 -3

Step Justification
Step 1: x over 3 = -4 - 8 The same number -8 can be added to both sides of the equation
Step 2: x over 3 = -4 Adding -8 and 4 on the right hand side
Step 3: x = -4 ÷ 3 The same number 3 can be divided on both sides of the equation
Step 4: x = -1.33 Dividing -4 by 3 on the right hand side

Answer 6

which do you think it is?

Answer 7

i don't know.

Answer 8

write out the equation, solve it, check it and then see which matches. that's what i did.

Answer 9

\(8+\frac{x}{3}=4\)

Answer 10

okay i don't know how, that is why i need help.

Answer 11

to solve this, what's the first step?

Answer 12

subtract ?

Answer 13

subtract what?

Answer 14

the 4 and 8

Answer 15

and why?

Answer 16

because whatever you do to one side you have to do the other.

Answer 17

yes, but the goal here is to isolate the term with the x in it. as such, you subtract 8 from both sides. does that make sense?

Answer 18

yes

Answer 19

so what is the new equation?

Answer 20

x=-4

Answer 21

no, \(\frac{x}{3}=-4\)

Answer 22

yeah

Answer 23

the i divide?

Answer 24

then *

Answer 25

no you multiply.

Answer 26

and get 12