3 years ago

When rust forms on a piece of iron, what evidence do you have that a chemical reaction has taken place??

Chemistry

1 answer:

-BARSIC- [3]3 years ago

7 0

Answer:

You know that a chemical reaction has taken place because there is a material a color change.

Explanation:

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Which of these statements is false?

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Answer:

The answer is b

Explanation:

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3 years ago

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Brodation<br>number of oxygen in F2O is.

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Oxidation number of F2O = 0−(−1×2)

State of oxygen will be=+2

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3 years ago

Mention the reason why aquatic plants have air filled tissues.

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Aquatic plants have aur filled tissues to make them easy to float.....

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3 years ago

The Ka for formic acid (HCO2H) is 1.8 × 10-4. What is the pH of a 0.35 M aqueous solution of sodium formate (NaHCO2)?

anzhelika [568]

Answer:

9.36

Explanation:

Sodium formate is the conjugate base of formic acid.

Also,

$K_a\times K_b=K_w$

$K_b$ for sodium formate is $K_b=\frac {K_w}{K_a}$

Given that:

$K_a$ of formic acid = $1.8\times 10^{-4}$

And, $K_w=10^{-14}$

So,

$K_b=\frac {10^{-14}}{1.8\times 10^{-4}}$

$K_b=5.5556\times 10^{-11}$

Concentration = 0.35 M

HCOONa ⇒ Na⁺ + HCOO⁻

Consider the ICE take for the formate ion as:

HCOO⁻ + H₂O ⇄ HCOOH + OH⁻

At t=0 0.35 - -

At t =equilibrium (0.35-x) x x

The expression for dissociation constant of sodium formate is:

$K_{b}=\frac {[OH^-][HCOOH]}{[HCOO^-]}$

$5.5556\times 10^{-11}=\frac {x^2}{0.35-x}$

Solving for x, we get:

x = 0.44×10⁻⁵ M

pOH = -log[OH⁻] = -log(0.44×10⁻⁵) = 4.64

pH + pOH = 14

So,

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3 years ago

Terry, a student, performs a titration. He completes these steps as part of his titration procedure: 1. He cleans and rinses a b

Contact [7]

Answer:

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D is the answer because 2 is needed to know

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