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2 years ago

What is the concentration of hydronium ions after a 100ml solution of 0.02m magnesium hydroxide and 100ml of 0.05m nitric acid?

1 answer:

4 0

$Mg(OH)_2 + 2HNO_3 ---\ \textgreater \ Mg(NO_3)_2 + 2H_2O$

That is the balanced chemical equation.

Before reaction,
milli-moles of Mg(OH)2 = 100 x 0.02 = 2
milli-moles of HNO3 = 100 x 0.05 = 5

After reaction:
Mg(OH)2 is limiting reagent. It will react completely leaving some HNO3 behind.
milli-moles of HNO3 react = 2 x coefficient of HNO3 = 2 x 2 = 4

milli-moles of HNO3 left = 5 -4 = 1

Now, total volume = 100+ 100 = 200 mL

It is asked for hydronium ion concentration, which is basically hydrogen ion conc.
1 HNO3 will dissociate to give 1 H+ ion.

so, milli-moles of H+ = 1

So, concentration of H+ or hydronium(H3O+) = 1 / 200 = 0.005

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Why is it important to have regular supervision of the weight and measurements in the market

Sergio [31]

Answer:

Supervision of weights and measures promotes accurate measurements of goods and services to ensure that everybody gets a fair trade in the marketplace. Not so coincidentally it also is a deterrent to ensure that traders are being honest in their trade practises.

Explanation:

4 0

2 years ago

One container of turns costs 4 dollars. Each container has eighty 1g tablets. Assume each turns is 40% caco₃. Using only turns,

stealth61 [152]

<u>Answer:</u> The cost is coming out to be $ 1.25

<u>Explanation:</u>

To calculate the number of moles for given molarity, we use the equation:

$\text{Molarity of the solution}=\frac{\text{Moles of solute}}{\text{Volume of solution (in L)}}$

Molarity of HCl solution = 0.4 M

Volume of solution = 0.5 L

Putting values in equation 1, we get:

$0.4M=\frac{\text{Moles of HCl}}{0.5L}\\\\\text{Moles of HCl}=(0.4mol/L\times 0.5L}=0.2mol$

The chemical equation for the reaction of HCl and calcium carbonate follows:

$CaCO_3+2HCl\rightarrow CaCl_2+H_2O+CO_2$

By Stoichiometry of the reaction:

2 moles of HCl reacts with 1 mole of calcium carbonate

So, 0.2 moles of HCl will react with = $\frac{1}{2}\times 0.2=0.1mol$ of calcium carbonate

To calculate the mass of calcium carbonate for given moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$

Molar mass of calcium carbonate = 100 g/mol

Moles of calcium carbonate = 0.1 moles

Putting values in equation 1, we get:

$0.1mol=\frac{\text{Mass of calcium carbonate}}{100g/mol}\\\\\text{Mass of calcium carbonate}=(0.1mol\times 100g/mol)=10g$

Calculating the mass of calcium carbonate in 1 container:

We are given:

One container contains eighty 1 g of tablets, this means that in total 80 g of tablets are there.

Every container has 40 % calcium carbonate.

Mass of calcium carbonate in 1 container = 40 % of 80 g = $\frac{40}{100}\times 80=32g$

Calculating the containers for amount of calcium carbonate that neutralized HCl by using unitary method:

32 grams of calcium carbonate is present in 1 container

So, 10 g of calcium carbonate will be present in = $\frac{1}{32}\times 10=0.3125$ container

Calculating the cost of turns:

1 container of turns costs $4

So, 0.3125 containers of turns will cost = $\frac{\$ 4}{1}\times 0.3125=\$ 1.25$

Hence, the cost is coming out to be $ 1.25

4 0

2 years ago

Use coulomb's law to calculate the ionization energy in kj/mol of an atom composed of a proton and an electron separated by 185.

Tems11 [23]

Coulomb's law mathematically is:
F = kQ₁Q₂/r²
we integrate this with respect to distance to obtain the expression for energy:
E = kQ₁Q₂/r; where k is the Coulomb's constant = 9 x 10⁹; Q are the charges, r is the seperation
Charge on proton = charge on electron = 1.6 x 10⁻¹⁹ C
E = (9 x 10⁹ x 1.6 x 10⁻¹⁹ x 1.6 x 10⁻¹⁹) / (185 x 10⁻¹²)
E = 1.24 x 10⁻¹⁸ Joules per proton/electron pair
Number of pairs in one mole = 6.02 x 10²³
Energy = 6.02 x 10²³ x 1.24 x 10⁻¹⁸
= 746.5 kJ

5 0

2 years ago

Read 2 more answers

A mixture of gases A2 and B2 are introduced to a slender metal cylinder that has one end closed and the other fitted with a pist

REY [17]

Answer:

q < 0, w > 0, the sign of ΔE cannot be determined from the information given

Explanation:

Determination of sign of q

Temperature of the water bath before the reaction = 25 °C

Temperature of the water bath after the completion of the reaction = 28 °C

After the completion of the reaction, temperature of the water bath is increased that means heat is released during the reaction and flows out of the system.

If heat is absorbed by the system, then q is indicated by positive sign and if heat is released by the system, then q is indicated by negative sign.

As in the given case, heat is released by the system, so sign of q is negative, or q < 0

Determination of sign of w

After the completion of the reaction, piston moved downward, that means volume of the system decreases or compression occur. During the compression, work is done on the system.

if work is done on the system, sign of w is positive.

If work is done by the system, sign of w is negative.

In the given case, work is done on the system, therefore sign of w is positive, or w > 0

Determination of sign of ΔE

Relationship between ΔE, q and w is given by first law of thermodynamics:

ΔE = q + w

In this case, q is positive and w is negative, so the sign of ΔE depends of magnitude of q and w. As magnitude of w and q cannot be determined in this case, thus, the given information is insufficient for the determination of sign of ΔE.

So, among the given option, option c is correct.

q < 0, w > 0, the sign of ΔE cannot be determined from the information given

3 0

2 years ago

If consumers pay $15 for an apple pie from Lake Huron Pie Company and the cost “from field to table” of the pie is $10, which of

Novosadov [1.4K]

The answer you are looking for is d

7 0

2 years ago

Read 2 more answers