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Travka [436]
2 years ago
15

Which of these is an indication that a chemical reaction has occurred? (boiling of a substance ,freezing of a substance, formati

on of a gas, melting of a substance)
Chemistry
2 answers:
Readme [11.4K]2 years ago
8 0

Answer:

Boiling of a substance

Explanation:

When something is boiled, heat is released to the surrounding, making it an exothermic reaction (a type of chemical reaction)

Anna007 [38]2 years ago
5 0

Answer: the answer is formation of gas

Explanation: i took the qwiz and boliing water is wrong

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The area that includes everything between the cell membrane and the nucleus of a cell is called the ___________.
m_a_m_a [10]

The answer is C. Cytoplasm

happy to help!!

7 0
2 years ago
Read 2 more answers
Please help me
Wittaler [7]

Answer:

pH = 6.999

The solution is acidic.

Explanation:

HBr is a strong acid, a very strong one.

In water, this acid is totally dissociated.

HBr + H₂O  →  H₃O⁺  +  Br⁻

We can think pH, as - log 7.75×10⁻¹² but this is 11.1

acid pH can't never be higher than 7.

We apply the charge balance:

[H⁺] = [Br⁻] + [OH⁻]

All the protons come from the bromide and the OH⁻ that come from water.

We can also think [OH⁻] = Kw / [H⁺] so:

[H⁺] = [Br⁻] + Kw / [H⁺]

Now, our unknown is [H⁺]

[H⁺] =  7.75×10⁻¹² + 1×10⁻¹⁴ / [H⁺]

[H⁺] = (7.75×10⁻¹² [H⁺] + 1×10⁻¹⁴) /  [H⁺]

This is quadratic equation:  [H⁺]² - 7.75×10⁻¹² [H⁺] - 1×10⁻¹⁴

a = 1 ; b = - 7.75×10⁻¹² ; c = -1×10⁻¹⁴

(-b +- √(b² - 4ac) / (2a)

[H⁺] = 1.000038751×10⁻⁷

- log [H⁺] = pH → 6.999

A very strong acid as HBr, in this case, it is so diluted that its pH is almost neutral.

8 0
3 years ago
When zinc and HCl are reacted, the product is hydrogen gas. You can measure the reaction rate by measuring what?
Zarrin [17]

Answer:

measuring the consumption of the products and the rate of conversion of products to reagents

Explanation:

It must be taken into account that the reaction rate also depends on the presence of a catalyst, since these advance the rate of the reaction.

6 0
2 years ago
An artifact contains one-fourth as much carbon-14 as the atmosphere. how old is the artifact
Nikolay [14]
<h3><u>Answer;</u></h3>

= 11,460 years

<h3><u>Explanation;</u></h3>
  • <em><u>The half life of Carbon-14 is 5,730 years . Half life is the time taken by a radioactive material to decay by half of its original mass.  Therefore, it  would take a time of 5730 years for a sample of 100 g of carbon-14 to decay to 50 grams</u></em>

<em>The initial amount of carbon-14 in this case was 1 whole; thus; </em>

<em>1 → 1/2 →1/4</em>

<em>To contain 1/4 of the value, 2 half-lives have passed. </em>

<em>But, 1 half life = 5,730 years</em>

<em>Therefore; The artifact is is therefore: 2 x 5,730 </em>

<em>          = 11,460 years </em>

4 0
2 years ago
Read 2 more answers
Rank the following by their miscibility in
tatuchka [14]

Answer:

<h2>2. H2O < CH3OH < CH3CH2OH < C9H20</h2>

Explanation:

Decane is a hydrocarbon so it is a non-polar molecule. Non-polar molecules are soluble in non-polar molecules and polar molecules are soluble in polar molecules. Water is a polar molecule so it is least soluble in decane molecule and C_{9}H_{20} is a non-polar molecule so it is most soluble in decane molecule. Methanol and ethanol are the derivatives of hydrocarbon so they have more solubility than water but less solubility than nonane molecules.

6 0
3 years ago
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