There are 3.45 moles of (nh4)2 so4, how many grams is this?

455.4 g

Explanation:

Data given:

no. of moles of (NH₄)₂SO₄= 3.45 mol

mass of (NH₄)₂SO₄ = ?

Solution

Formula will be used

           no.of moles = mass in grams / molar mass

Rearrange the above equation for mass

           mass in grams = no. of moles x molar mass . . . . . . . . (1)

molar mass of (NH₄)₂SO₄

molar mass of (NH₄)₂SO₄ = 2(14 + 4(1)) + 32 + 4(16)

molar mass of (NH₄)₂SO₄ = 2 (14 +4) + 32 + 64  

molar mass of (NH₄)₂SO₄ = 2 (18) + 32 + 64

molar mass of (NH₄)₂SO₄ = 36 + 32 + 64 = 132 g/mol

Put values in equation 1

           mass in grams = 3.45 mole x 132 g/mol

           mass in grams = 455.4 g

So,

mass of (NH₄)₂SO₄ = 455.4 g

linda: 3 ; laura: 15

step-by-step explanation:

note that linda + laura's age is 18, and that linda is 12 years younger than her sister.

let "linda" = x , "laura" = y:

x + y = 18

x = y - 12

first, plug in y - 12 for x in the first equation:

(y - 12) + y = 18

simplify.

2y - 12 = 18

isolate the variable (y). note the equal sign, what you do to one side, you do to the other. do the opposite of pemdas. first add, then divide.

2y - 12 (+12) = 18 (+12)

2y = 18 + 12

2y = 30

(2y)/2 = (30)/2

y = 30/2

y = 15

next, plug in 15 for y in the second equation (the other equation would work too).

x = y - 12

x = (15) - 12

x = 3

linda's age is 3, laura's age is 15.

~

3 hours because it is a decent distance.