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3 years ago

How do I do question number 3? And what is the answer?

Chemistry

1 answer:

shutvik [7]3 years ago

3 0

Answer:

60.02 g.

Explanation:

It is clear from the balanced equation:

Mg + 2HCl → MgCl₂ + H₂.

that 1.0 mole of Mg reacts with 2.0 moles of HCl to produce 1.0 mole of MgCl₂ and 1.0 moles of H₂.

20.0 g of Mg reacts with excess HCl. To calculate the no. of grams of HCl that reacted, we should calculate the no. of moles of Mg:

no. of moles of Mg = mass/atomic mass = (20.0 g)/(24.3 g/mol) = 0.823 mol.

From the balanced equation; every 1.0 mol of Mg reacts with 2 moles of HCl.

∴ 0.833 mol of Mg will react with (2 x 0.833 mol = 1.646 mol) of HCl.

∴ The mass of reacted HCl = no. of moles x molar mass = (1.646 mol)(36.46 g/mol) = 60.02 g.

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Pls help me I don’t know what to dooooo

Ivan

Molarity = moles of solute/volume of solution in liters.

The solute here is NaCl, of which we have 46.5 g. To calculate the molarity of an NaCl solution, we need to know the number of moles of NaCl. To convert from grams to moles, we divide the mass by the molar mass of NaCl. The molar mass of NaCl is the sum of the atomic masses of Na and Cl: 23 amu + 35 amu = 58 amu. For our purposes, we can regard amu as equivalent to grams/mole.

(46.5 g)/(58 g/mol) = 0.8017 moles NaCl.

Now that we know both the number of moles of our NaCl solute and the volume of the solution, we can calculate the molarity:

(0.8017 moles NaCl)/(2.2 L) = 0.364 M.

5 0

3 years ago

If a sample of N2 gas has an initial pressure of 500 Torr and volume of 0.5 L, what will the final volume be if the pressure is

kherson [118]

Answer:

V₂ = 0.4 L

Explanation:

Data:

P₁ (initial pressure) = 500 torr
V₁ (initial volume) = 0.5 L
P₂ (final pressure) = 700 torr

Wanted:

V₂ (final volume)

Equation:

P₁V₁ = P₂V₂ → V₂ = P₁V₁ / P₂

Solution:

V₂ = $\frac{(500 torr)(0.5 L)}{700 torr}$ = 0.3571 L or 0.4 L

8 0

2 years ago

...................................................................

neonofarm [45]

Answer:

Imao ;/

Explanation:

5 0

3 years ago

Read 2 more answers

Round 0.007062 to 4 significant numbers

mafiozo [28]

Answer

its already rounded

Explanation:

8 0

3 years ago

3.5g of a Certain compound X, known to be made of carbon, hydrogen, and perhaps oxygen, and to have a molecular molar mass of 15

shutvik [7]

Answer:

C₅H₁₀O₅

Explanation:

1. Calculate the mass of each element in 2.78 mg of X.

(a) Mass of C

$\text{Mass of C} = \text{5.13 g CO}_{2}\times \dfrac{\text{12.01 g C}}{\text{44.01 g }\text{CO}_{2}}= \text{1.400 g C}$

(b) Mass of H

$\text{Mass of H} = \text{2.10 g H$_{2}$O}\times \dfrac{\text{2.016 g H}}{\text{18.02 g H$_{2}$O}} = \text{0.2349 g H}$

(c) Mass of O

Mass of O = 3.5 - 1.400 - 0.2349 = 1.87 g

2. Calculate the moles of each element

$\text{Moles of C = 1400 mg C}\times\dfrac{\text{1 mmol C}}{\text{12.01 mg C }} = \text{116.6 mmol C}\\\\\text{Moles of H = 234.9 mg H} \times \dfrac{\text{1 mmol H}}{\text{1.008 mg H}} = \text{233.1 mmol H}\\\\\text{Moles of O = 1870 mg O} \times \dfrac{\text{1 mmol O}}{\text{16.00 mg O}} = \text{116 mmol O}$

3. Calculate the molar ratios

Divide all moles by the smallest number of moles.

$\text{C: } \dfrac{116.6}{116.6}= 1\\\\\text{H: } \dfrac{233.1}{116.6} = 1.999\\\\\text{O: } \dfrac{116}{116.6} = 1.00$

4. Round the ratios to the nearest integer

C:H:O = 1:2:1

5. Write the empirical formula

The empirical formula is CH₂O.

6. Calculate the molecular formula.

EF Mass = (12.01 + 2.016 + 16.00) u = 30.03 u

The molecular formula is an integral multiple of the empirical formula.

MF = (EF)ₙ

$n = \dfrac{\text{MF Mass}}{\text{EF Mass }} = \dfrac{\text{150 u}}{\text{30.03 u}} = 5.00 \approx 5$

MF = (CH₂O)₅ = C₅H₁₀O₅

The molecular formula of X is C₅H₁₀O₅.

8 0

3 years ago