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Kaylis [27]
3 years ago
5

In class, it was mentioned that at 25 °C, the pH of pure water is 7.00 becuase Kw = 1.0 × 10−14. At other temperatures, the pH v

alue of pure water will be different than 7.00 becuase the value of Kw changes. Suppose that at a temperature different than 25 °C, the pH of pure water was measured and found to be 7.27. What must the value of Kw be equal to at this second temperature?
Chemistry
1 answer:
ivanzaharov [21]3 years ago
5 0

Answer:

Kw = 2.88 × 10⁻¹⁵

Explanation:

Let's consider the dissociation of water.

H₂O(l) ⇄ H⁺(aq) + OH⁻(aq)

The equilibrium constant Kw is:

Kw = [H⁺].[OH⁻]

If pH = 7.27, we can find [H⁺]:

pH = -log [H⁺]

H⁺ = anti log (-pH) = anti log (-7.27) = 5.37 × 10⁻⁸ M

According to the balanced equation, 1 mole of H⁺ is produced per mole of OH⁻. So, [H⁺] = [OH⁻] = 5.37 × 10⁻⁸ M

Then,

Kw = [H⁺].[OH⁻]= (5.37 × 10⁻⁸)² = 2.88 × 10⁻¹⁵

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nexus9112 [7]

Answer:

<u>2</u> XE + <u>1</u> AB. --> <u>1</u> AE2 + <u>2</u> XB

Above equation is now balanced

6 0
3 years ago
In the reaction Na2CO3 + 2HCl → 2NaCl + CO2 + H2O, how many grams of CO2 are produced when 7.5 moles of HCl is fully reacted?
Sidana [21]

Answer:

165 of CO₂.

Explanation:

In the reaction:

Na2CO3 + 2HCl → 2NaCl + CO2 + H2O

2 moles of HCl reacts producing 1 mole o CO₂

If 7.5 moles of HCl reacts, moles of CO₂ produced are:

7.5 moles of HCl ₓ ( 1 mol CO₂ / 2 mol HCl) = 3.75 mol CO₂. As molar mass of CO₂ is 44g/mol, mass of CO₂ is:

3.75 mol CO₂ ₓ (44g / 1mol) = <em>165 of CO₂ </em>

8 0
3 years ago
Read 2 more answers
If light is what is virtually the fastest thing ever then how can the dark keep up with it?
Sav [38]
Dark is just absence of light like if the re container a and container b u nee to pour hcl from a to so a has hcl while b has absence of hcl

tell me if u need more examples.hope it helps

5 0
3 years ago
A 45ml of a 4M solution of CaBr2 contains how many grams of CaBr2?
natta225 [31]

The required mass of calcium bromide is 35.98 grams.

<h3>What is molarity?</h3>

Molarity is any solution is define as the number of moles of solute present in per liter of solution as;

M = n/V, where

  • M = molarity = 4M
  • V = volume = 45mL = 0.045L

Moles will be calculated by using the above equation as:

n = (4)(0.045) = 0.18 mole

Relation between the mass and moles of any substance will be represented as:

n = W/M, where

  • W = given mass
  • M = molar mass

Mass of CaBr₂ = (0.18mol)(199.89g/mol) = 35.98g

Hence required mass of CaBr₂ is 35.98 grams.

To know more about molarity, visit the below link:
brainly.com/question/22283918

#SPJ1

6 0
2 years ago
The antibiotic doxycycline is used to treat Lyme disease. A 100 mg dose of the antibiotic consists of 59.5 mg of C, 5.40 mg of H
never [62]

Answer:

C₁₁H₁₂NO₄

Explanation:

In order to determine the empirical formula of doxycycline, we need to follow a series of steps.

Step 1: Determine the centesimal composition

C: 59.5 mg/100 mg × 100% = 59.5%

H: 5.40 mg/100 mg × 100% = 5.40%

N: 6.30 mg/100 mg × 100% = 6.30%

O: 28.8 mg/100 mg × 100% = 28.8%

Step 2: Divide each percentage by the atomic mass of the element

C: 59.5 /12.0 = 4.96

H: 5.40/1.00 = 5.40

N: 6.30/14.0 = 0.450

O: 28.8/16.0 = 1.80

Step 3: Divide all the numbers by the smallest one

C: 4.96/0.450 = 11

H: 5.40/0.450 = 12

N: 0.450/0.450 = 1

O: 1.80/0.450 = 4

The empirical formula of doxycycline is C₁₁H₁₂NO₄

5 0
3 years ago
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