All categories

2 years ago

The molar mass of the compound was found to be 30.069 g/mol. what is the molecular formula?

1 answer:

4 0

It will be hard to found the compound molecular weight just by the weight. I can think 2 kind of atom for this configuration.
First, it was NO or nitric oxide. It molecular weight is 16+14= 30. But if you search the exact weight is 30.01 g/mol

Second, it was (CH3)2 or ethane. The molecular weight is 2*12+ 6*1= 30. But if you search the exact weight is 30.07 g/mol. So it more likely to be ethane.

You might be interested in

A scientist is at the hospital visiting a friend's young daughter, who has been

slava [35]

Answer:

Explanation:

The scientist identifies the need to make a drug to cure the respiratory illnesses.

5 0

2 years ago

Cyclohexane has a freezing point of 6.50 ∘C and a Kf of 20.0 ∘C/m. What is the freezing point of a solution made by dissolving 0

ExtremeBDS [4]

Answer:

The freezing point will be $2.9^{0}C$

Explanation:

The depression in freezing point is a colligative property.

It is related to molality as:

$Depressioninfreezing point=K_{f}Xmolality$

Where

Kf= $20\frac{^{0}C}{m}$

the molality is calculated as:

$molality=\frac{moles_{solute}}{mass_{solvent}}$

$moles=\frac{mass}{molarmass}=\frac{0.694}{154}=0.0045mol$

$massofcyclohexane=25g=0.025Kg$

$molarity=\frac{0.0045}{0.025}=0.18m$

Depression in freezing point = $20X0.18=3.6^{0}C$

The new freezing point = $6.5^{0}C-3.6^{0}C=2.9^{0}C$

5 0

2 years ago

2.00 g of an unknown gas at STP fills a 500. mL flask. What is the molar mass of the gas?

otez555 [7]

Answer:

100g/mol

Explanation:

Given parameters:

Mass of unknown gas = 2g

Volume of gas in flask = 500mL = 0.5dm³

Unknown:

Molar mass of gas = ?

Solution:

Since we know the gas is at STP;

1 mole of substance occupies 22.4dm³ of space at STP

Therefore,

0.5dm³ will have 0.02mole at STP

Now;

Number of moles = $\frac{mass}{molar mass}$

Molar mass = $\frac{mass}{number of moles}$ = $\frac{2}{0.02}$ = 100g/mol

4 0

2 years ago

How many moles of FeS2 are required to produce 32g of SO2?

nirvana33 [79]

Answer:

So, the right answer is

No. of moles of FeS₂ = 0.25 mole

Explanation:

From the balanced

4 FeS2 + 11 O2 → 2 Fe2O3 + 8 SO2

it is clear that 4 mol FeS₂ react with O₂ to give Fe₂O₃ and 8 mol of SO₂

First, we have to convert mass of SO₂ into No. of moles as following:

SO₂ has molar mass = 64 g/mol

No. of moles of SO₂ = (mass / molar mass) = (32 g / 64 g/mol) = 0.5 mol

we know that

4 mol FeS₂ gives→ 8 mol of SO₂

1 mol FeS₂ gives→ 2 mol of SO₂

??? mol FeS₂ gives→ 0.5 mol of SO₂

No. of moles of FeS₂ = (0.5 mol * 1 mol ) / 2 mol = 0.25 mol

So, the right answer is

No. of moles of FeS₂ = 0.25 mol

7 0

2 years ago

A sample contains 2.2 g of the radioisotope niobium-91 and 15.4 g of its daughter isotope, zirconium-91. how many half-lives hav

dybincka [34]

Answer: 3

Explanation: This is a radioactive decay and all the radioactive process follows first order kinetics.

Equation for the reaction of decay of $_{19}^{40}\textrm{K}$ radioisotope follows:

$Moles of zirconium=\frac{\text{Given mass}}{\text{Molar mass}}=\frac{15.4}{91}=0.17moles$

$Moles of niobium=\frac{\text{Given mass}}{\text{Molar mass}}=\frac{2.2}{91}=0.024moles$

$_{41}^{91}\textrm{Nb}\rightarrow _{40}^{91}\textrm{Zr}+_{+1}^0e$

By the stoichiometry of above reaction,

1 mole of $_{40}^{91}\textrm{Zr}$ is produced by 1 mole $_{41}^{91}\textrm{Nb}$

So, 0.17 moles of $_{40}^{91}\textrm{Zr}$ will be produced by = $\frac{1}{1}\times 0.17=0.17\text{ moles of }_{40}^{91}\textrm{Nb}$

Amount of $_{82}^{212}\textrm{K}$

decomposed will be = 0.17 moles

Initial amount of $_{40}^{91}\textrm{Nb}$ will be = Amount decomposed + Amount left = (0.17 + 0.024)moles =0.194 moles

$a=\frac{a_o}{2^n}$

where,

a = amount of reactant left after n-half lives = 0.024

$a_o$ = Initial amount of the reactant = 0.194

n = number of half lives= ?

Putting values in above equation, we get:

$0.024=\frac{0.194}{2^n}$

$n=3$

Therefore, 3 half lives have passed.

3 0

2 years ago

Read 2 more answers