All categories

2 years ago

The pH of a solution is 3.81. What is the OH concentration in the solution?

Chemistry

1 answer:

disa [49]2 years ago

3 0

Answer:

6.46 × 10⁻¹¹ M

Explanation:

Step 1: Given data

pH of the solution: 3.81

Step 2: Calculate the pOH of the solution

We will use the following expression.

pH + pOH = 14.00

pOH = 14.00 - pH = 14.00 - 3.81 = 10.19

Step 3: Calculate the concentration of OH⁻ ions

We will use the definition of pOH.

pOH = -log [OH⁻]

[OH⁻] = antilog -pOH = antilog -10.19 = 6.46 × 10⁻¹¹ M

You might be interested in

What is the process of grouping similar things together

andre [41]

Answer:

See Explanation

Explanation:

Mathematically, this means to combine like terms, such as terms with the same variable. In chemistry, this can refer to polar objects combining with polar objects while nonpolar objects combine with nonpolar objects.

8 0

3 years ago

A 0.590 gram sample of a metal, M, reacts completely with sulfuric acid according to:M(s) +H2SO4(aq) --> MSO4(aq) +H2(g)A vol

photoshop1234 [79]

Answer:

MM = 58.41 g

Explanation:

First, the data we have is according to the hydrogen which is exerting pressure. To solve this, we need to use the ideal gas equation:

PV = nRT (1)

the molar mass of any compound is calculated like this:

MM = m/n (2)

So, from (1) we solve for the moles (n) and then, this value is replace in (2).

However, before we do all that, we need to gather all the correct data.

All the species in the reaction are solid or aqueous state, with the exception of hydrogen, which is gaseous. Hydrogen is collected over water, therefore, is exerting some pressure too. The problem is not indicating if the acid or any other species is exerting pressure, so we will assume that only hydrogen and water are exerting pressure.

The total pressure exerted by the system would be:

P = Pw + PH2 (3)

We already know the total pressure which is 756 torr.

This experiment is taking place at 25 °C (298.15 K), and at this temperature, we have a reported value for water pressure which is 23.8 Torr.

Let's solve for PH2:

PH2 = P - Pw

PH2 = 756 - 23 = 733 Torr

Now, with this value, and the volume and temperature, we can calculate the moles of H2:

n = PV/RT

But first, let's convert the pressure to atm:

PH2 = 733 Torr / 760 torr * 1 atm = 0.9644 atm

now, solving for n:

n = 0.9644 * (0.255) / 0.082 * 298.15

n = 0.0101 moles

Now that we have the moles, we know that the metal and the hydrogen has a mole ratio of 1:1 according to the reaction, so, this means that:

moles M = moles H2 = 0.0101 moles

We have the moles of the metal and the mass, we can calculate the molar mass using expression (2):

MM = 0.590/0.0101

MM = 58.41 g/mol

This is the molar mass of the metal

8 0

3 years ago

CaC2 + 2H2O ➞ C2H2 + Ca(OH)2

Paraphin [41]

Answer:

A. 0.5 mole of Ca(OH)₂.

B. 4.37 moles of H₂O.

Explanation:

The balanced equation for the reaction is given below:

CaC₂ + 2H₂O —> C₂H₂ + Ca(OH)₂

Next, we shall determine the mass of CaC₂ that reacted and the mass of C₂H₂ produced from the balanced equation. This can be obtained as follow:

Molar mass of CaC₂ = 40 + (12×2)

= 40 + 24

= 64 g/mol

Mass of CaC₂ from the balanced equation = 1 × 64 = 64 g

Molar mass of C₂H₂ = (12×2) + (2×1)

= 24 + 2

= 26 g/mol

Mass of C₂H₂ from the balanced equation = 1 × 26 = 26 g

SUMMARY:

From the balanced equation above,

64 g of CaC₂ reacted with 2 moles of H₂O to produce 26 g of C₂H₂ and 1 mole of Ca(OH)₂.

A. Determination of the number of mole of Ca(OH)₂ produced by the reaction of 32.0 g of CaC₂.

From the balanced equation above,

64 g of CaC₂ reacted to produce 1 mole of Ca(OH)₂.

Therefore, 32 g of CaC₂ will react to produce = (32 × 1)/64 = 0.5 mole of Ca(OH)₂.

Thus, 0.5 mole of Ca(OH)₂ were obtained from the reaction.

B. Determination of the number of mole of H₂O needed to produce 56.8 g C₂H₂.

From the balanced equation above,

2 moles of H₂O reacted to produce 26 g of C₂H₂.

Therefore, Xmol of H₂O will react to produce 56.8 g C₂H₂ i.e

Xmol of H₂O = (2 × 56.8)/26

Xmol of H₂O = 4.37 moles

Thus, 4.37 moles of H₂O is needed for the reaction.

3 0

2 years ago

What is the average yearly rate of change of carbon-14 during the first 5000 years?

erica [24]

Answer:

The average yearly rate of change of carbon-14 during the first 5000 years = 0.0004538 grams per year

Explanation:

Given that the mass of the carbon 14 at the start = 5 gram

At the end of 5,000 years we will have;

$A = A_0 \times e^{-\lambda \times t}$

Where

A = The amount of carbon 14 left

A₀ = The starting amount of carbon 14

e = Constant = 2.71828

$T_{1/2}$ = The half life

$\lambda = 0.693/T_{1/2}$

t = The time elapsed = 5000 years

λ = 0.693/ $T_{1/2}$ = 0.693/5730 = 0.0001209424

Therefore;

A = 5 × e^(-0.0001209424×5000) = 2.7312 grams

Therefore, the amount of carbon 14 decayed in the 5000 years is the difference in mass between the starting amount and the amount left

The amount of carbon 14 decayed = 5 - 2.7312 = 2.2688 grams

The average yearly rate of change of carbon-14 during the first 5000 years is therefore;

2.2688 grams/(5000 years) = 0.0004538 grams per year

The average yearly rate of change of carbon-14 during the first 5000 years = 0.0004538 grams per year.

5 0

3 years ago

What is the empirical formula of a compound with a % composition of 40.1% sulfur and 59.9% oxygen?

olga_2 [115]

Answer:

The empirical formula is SO

Explanation:

The empirical formula of a chemical compound is the simplest positive integer ratio of atoms present in a compound.

Given 40.1% Sulphur and 59.9% oxygen.

We have to assume the mass of the compound to make our calculations easy.

Let's assume that the mass of the compound is 100g, that the mass of sulphur will be 40.1g and the mass of oxygen will then be 59.9g.

Number of moles= reacting mass/ molar mass

Molar mass of Sulphur = 32g/mol

Molar mass of Oxygen = 16g/mol

No of moles of S= 40.1g/100g

=0.401 moles of S

No of moles of O = 59.9g/100g

=0.599 moles of O

•These are the relative mole ratios for the compound,

•They need to be converted from decimals into whole numbers

•Turn mole ratio into whole number ratio by dividing by all the elements by the least/smallest number of moles calculated.

Number of moles of S = 0.401moles/0.401 = 1 mol S

Number of moles of O = 0.599moles/0.401 = 1.49 mol O which is approximately 1 (to the nearest whole number, considering it tenths' value which is 4 and less than 5)

The empirical formula is therefore SO.

4 0

3 years ago

The pH of a solution is 3.81. What is the OH concentration in the solution?​

The pH of a solution is 3.81. What is the OH concentration in the solution?