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3 years ago

What is chemical change

Chemistry

1 answer:

Igoryamba3 years ago

8 0

Answer:

Chemical change is a chemical process that occurs when a substance combines with another to create an entirely new substance, this process is also called chemical synthesis

Explanation:

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In a titration of 0.5 M HCl and an unknown concentration NaOH, 25.0 ml of NaOH was required to completely neutralize 25.0 ml of

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When an acid is neutralized by a base, that means moles of H+ = moles of OH-

moles of H+ = 0.5 M * 0.025 L HCl = 0.0125 moles H+

moles of OH- should be equal to 0.0125 moles, so
0.0125 moles = (x) * 0.025 L NaOH

x is the concentration of NaOH, which we want to find.

x = 0.5 M

The correct answer is C) 0.5 M.

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3 years ago

What did the periodic table help scientists discover?

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Answer:

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3 years ago

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Select the correct answer. Clive finds that the water coming out of the faucet is a little muddy. He concludes that the color in

KiRa [710]

Answer:

A. observing

Explanation:

There are various steps that are involved in a scientific investigation. Observation is the first step of the scientific investigation. In this step, a close examination is laid on the investigation. Observation is collected with the senses and the information is gathered.

In the given excerpt, Clive missed the observation part of the scientific investigation. All the other three steps were followed by Clive. He was not able to observe the situation and so was not able to provide the answers to the questions asked by his classmates.

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3 years ago

Calculate how many times more soluble Mg(OH)2 is in pure water Based on the given value of the Ksp, 5.61×10−11, calculate the ra

maks197457 [2]

Answer:

molar solubility in water = 2.412 * 10^-4 mol/L

molar solubility of NaOH in 0.130M = 3.32 * 10^-9 mol/L

Mg(OH)2 is a factor 0.73*10^5 more soluble in pure water than in 0.130 M NaOH

Explanation:

The Ksp refers to the partial solubilization of a mostly insoluble salt. This is an equilibrium process.

The equation for the solubilization reaction of Mg(OH)2 can be given as:

Mg(OH)2 (s) → Mg2+ (aq) + 2OH– (aq)

Ksp can then be given as followed:

Ksp = [Mg^2+][OH^–]²

Step 2: Calculate the solubility in water

Mg(OH)2 (s) → Mg2+ (aq) + 2OH– (aq)

The mole ratio Mg^2+ with OH- is 1:2

So there will react X of Mg^2+ and 2X of OH-

The concentration at equilibrium will be XM Mg^2+ and 2X OH-

Ksp = [Mg^2+][OH^–]²

5.61*10^-11 = X * (2X)² = X *4X² = 4X³

X = 2.412 * 10^-4 mol/L = solubility in water

Step 3: Calculate solubility in 0.130 M NaOH

The initial concentration of Mg^2+ = 0 M

The initial concentration of OH- = 0.130 M

The mole ratio Mg^2+ with OH- is 1:2

So there will react X of Mg^2+ and 2X +0.130 for OH-

The concentration at equilibrium will be XM Mg^2+ and 0.130 + 2X OH-

The value of "[OH–] + 2X" is, because the very small value of X, equal to the value of [OH–] .

Let's consider:

[Mg+2] = X

[OH] = 0.130

Ksp = [Mg^2+][OH^–]²

5.61*10^-11 = X *(0.130)²

5.61*10^-11 = X * (0.130)^2

X = 3.32*10^-9 = solubility in 0.130 M NaOH

Step 4: Calculate how many times Mg(OH)2 is better soluble in pure water.

(2.412*10^-4)/ (3.32*10^-9) = 0.73 * 10^5

Mg(OH)2 is a factor 0.73*10^5 more soluble in pure water than in 0.130 M NaOH

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3 years ago

Which of the following is NOT an example of a chemical change? *

lord [1]

Grinding as it’s a physical not chemical change :)

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3 years ago