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3 years ago

Pls help me solve those.Thank youu!

Chemistry

1 answer:

xz_007 [3.2K]3 years ago

5 0

Answer:

2,3-dimethylpentanal

3,4-heptadienal

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You start with 2.5g of magnesium and add it to 400mL of CO2 at 23 o C and 1atm. How many grams of magnesium oxide will be formed

8090 [49]

Answer:

0.664 g are formed by the reaction.

Explanation:

First of all, we determine the reaction:

Mg + CO₂ → MgO + CO

We need to determine the moles of the CO₂ by the Ideal Gases Law.

We convert to L, the volume → 400 mL = 0.4L

T° → 23°C + 273 = 296K

P . V = n . R .T

n = P . V / R .T

n = (1 atm . 0.4L) / (0.082 . 296K) → 0.0165 moles

Moles of Mg → 2.5 g . 1mol / 24.3g = 0.103 moles

As ratio is 1:1, CO₂ is the limiting reactant.

For 1 mol of Mg, we need 1 mol of gas

Then, for 0.103 moles of Mg, we need 0.103 moles of gas, but we only have 0.0165 moles.

If we see the product side, ratio is also 1:1

0.0165 moles of CO₂ must produce 0.0165 moles of MgO.

We convert the moles to mass → 0.0165 mol . 40.3 g /1mol = 0.664 g

5 0

4 years ago

When 0.49 g of a molecular compound was dissolved in 20.00 g of cyclohexane, the freezing point of the solution was lowered by 3

IRISSAK [1]

Answer: The molecular mass of this compound is 131 g/mol

Explanation:

Depression in freezing point:

$\Delta T_f=i\times k_f\times \frac{w_2\times 1000}{M_2\times w_1}$

where,

$\Delta T_f$ = depression in freezing point = $3.9^oC$

$k_f$ = freezing point constant = $20.8^0C/m$

m = molality

i = Van't Hoff factor = 1 (for non-electrolyte)

$w_2$ = mass of solute = 0.49 g

$w_1$ = mass of solvent (cyclohexane) = 20.00 g

$M_2$ = molar mass of solute = ?

Now put all the given values in the above formula, we get:

$(3.9)^oC=1\times (20.8^oC/m)\times \frac{(0.49g)\times 1000}{M_2\times (20.00g)}$

$M_2=131g/mol$

Therefore, the molar mass of solute is 131 g/mol

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3 years ago

What properties do molecules usually share?

N76 [4]

They contain atoms including nucleus proton electron and neutron

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calculate the molality of commercial HCl solution which is 12.1Molarity, and has a density of 1.19g/mL, and is 37.2wt.%HCl.

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Answer:

0.44165 Molal

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4 years ago

The valance number of M is 3 . what is the formula of its phosphorus

lakkis [162]

The formula for phosphorus is P4

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