Will mark brainliest! explain why a mechanical wave does not exist in a vacuum.

answer:

7.5 mol  

step-by-step explanation:

step 1. balanced equation

c₃h₈ + 5o₂ ⟶ 3co₂ + 4h₂o

step 2. calculation:

you want to convert moles of c₃h₈ to moles of co₂

the molar ratio is 3 mol co₂: 1 mol c₃h₈

moles of co₂ = 2.5 mol c₃h₈ × (3 mol co₂/1 mol c₃h₈)

                      = 7.5 mol co₂

the reaction will form 7.5 mol of co₂.

answer:

ch₃o  

step-by-step explanation:

1. calculate the mass of each element

mass of c =   1.45 mg co₂ × (12.01 mg c/44.01 mg co₂)   = 0.3957 mg c

mass of h = 0.89 mg h₂o × (2.016 mg h/18.02 mg h₂o) = 0.0996 mg h

mass of o = mass of compound - mass of c - mass of h = (1.55 – 0.3957 – 0.0996) mg = 1.055 mg

2. calculate the moles of each element

moles of c = 0.3957 mg c × 1mmol c/12.01 mg c   = 0.03295 mol c

moles of h = 0.0996 mg h × 1 mmol h/1.008 mg h = 0.0988   mol h

moles of o = 1.055 mg o   × 1 mmol o/ 16.00 mg o = 0.06592 mol o

3. calculate the molar ratios

divide all moles by the smallest number of moles.

c:   0.032 95/0.032 95 = 1

h:     0.0988/0.032 95 = 2.998

o: 0.065 92/0.032 95   = 2.001

4. round the ratios to the nearest integer

c: h: o = 1: 3: 2

5. write the empirical formula

the empirical formula is ch₃o.

the answer is d. suspending a heavy weight with a strong chain.