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3 years ago

For which of the following activities might you want to hire a chemist?

Chemistry

2 answers:

Basile [38]3 years ago

7 0

Answer:

OPTION (A) : Testing a rock sample for gold content

Explanation:

For testing a rock sample of gold content you will need a Chemist. To test the material, the sample is rubbed on black stone which will leave a mark on the stone. This mark is tested by applying aqua fortis i.e nitric acid on the mark. If the mark gets dissolve then the material is not gold. If the mark sustain the it is further tested by applying aqua regia i.e nitric acid and hydrochloric acid which will prove the sample is of gold if it gets dissolve on using hydrochloric acid. The purity of the sample can be checked by differing the concentration of the aqua regia and comparing it with the gold material of the known purity.

valentinak56 [21]3 years ago

6 0

Answer:

Testing a rock sample for gold content

Explanation:

done the topic

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REALLY NEED HELP!!! Chemistry

kicyunya [14]

Answer:

C.) 2

Explanation:

The pH equation is:

pH = -log[H⁺]

In this equation, [H⁺] is the molarity of the acid. In this case, the acid is HCl. Molarity can be found using the equation:

Molarity (M) = moles / volume (L)

Since you were given moles and volume, you can find the molarity of HCl.

Molarity = moles / volume

Molarity = 0.01 moles / 1.00 L

Molarity = 0.01 M

Now, you can plug the molarity of the acid into the pH equation.

pH = -log[H⁺]

pH = -log[0.01]

pH = 2

3 0

2 years ago

One example of matter is

zaharov [31]

One example of matter could be <em>Light.</em>

6 0

3 years ago

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An atom has 24 protons and 23 electrons and 28 neutrons what charge does this atom have?

alina1380 [7]

Answer:

Explanation:

the number of protons tells you which element it is in the periodic table, you can notice that there is 1 less electron that then there is protons which means that the element had to give 1 electron away. When you get rid of 1 e- you have 1 proton more that electrons so that's why it's 1+

also the element is Cr

3 0

3 years ago

When reading any volume in the laboratory, we always read where the bottom of the water curve falls. This is called the______?

zavuch27 [327]

Answer: Meniscus

Explanation: There is a condition on reading volumes. For concave meniscus read volume in the lower part and for convex meniscus read volume at the upper part.

7 0

3 years ago

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The normal freezing point of water is 0.00 ⁰C. What is the freezing point of a solution containing450.0 mg of ethylene glycol (M

anyanavicka [17]

Answer:

Freezing T° of solution = - 8.98°C

Explanation:

We apply Freezing point depression to solve this problem, the colligative property that has this formula:

Freezing T° of pure solvent - Freezing T° of solution = Kf . m

Kf = 1.86°C/m, this is a constant which is unique for each solvent. In this case, we are using water

m = molality (moles of solute / 1kg of solvent)

We convert the mass of solvent from g to kg

1.5 g . 1kg/1000g = 0.0015 kg

We convert the mass of solute, to moles. Firstly we make this conversion, from mg to g → 450mg . 1g/1000mg = 0.450 g

0.450 g. 1mol / 62.07g = 7.25×10⁻³ moles

Molality → 7.25×10⁻³ mol / 0.0015 kg = 4.83 m

- Freezing T° of solution = 1.86°C /m . 4.83 m - Freezing T° of pure solvent

-Freezing T° of solution = 1.86°C /m . 4.83 m - 0°C

Freezing T° of solution = - 8.98°C

8 0

3 years ago

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