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3 years ago

Anyone please help I’m in summer school please

Chemistry

1 answer:

netineya [11]3 years ago

4 0

Answer:

1. Absolute time, also known as Newtonian time is a time that exists independent of the observer of the time, and therefore, can only be expressed through mathematics

Absolute dating is a dating method that makes use of the radioactive property of matter and is determined through dating of radioactive isotopes present

Absolute time (dating) is found through radioactive dating

2. Radioactive isotopes are atoms that have the property of unstable proton neutron combination or excess energy nucleus. They can be fined as unstable element

3. A stabilized isotope are the decay product atoms of the element which are non radioactive.

4. The half life is the time it takes the original isotope to decay into the decay product

5. To determine the age of a rock, the proportion of the original isotope to the amount of decay product in the rock is compared

6. The isotope used to date organic materials is carbon-14

7. The isotope used to date rocks with comparable age to the Earth is Uranium-238 that has a half life of 4.468 billion years

8. The half life of carbon-14 is only 5,700 years while the age of a dinosaur is between 245 and 66 million years ago, and therefore, carbon is absent in most fossils

9. Uranium-238 is only found in igneous or volcanic rocks and not in metamorphic rocks, therefore, fossils of dinosaur as well as other fossils that are buried in sedimentary materials, including sand and clay, cannot be determined by Uranium-238

Explanation:

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Automobile bodies contain significant amounts of iron. The iron is protected by the addition of zinc. This is called galvanizati

Oksana_A [137]

Answer: The balanced chemical equation is written below.

Explanation:

Galvanization is defined as the process in which a protective layer of zinc is applied to iron or steel to prevent the metal from rusting.

Zinc prevents the oxidation of iron and acts as a reducing agent in the process.

The half reaction for the process follows:

Oxidation half reaction: $Zn\rightarrow Zn^{2+}+2e^-$

Reduction half reaction: $Fe^{2+}+2e^-\rightarrow Fe$

Net chemical equation: $Zn+Fe^{2+}\rightarrow Zn^{2+}+Fe$

Hence, the balanced chemical equation is written above.

6 0

3 years ago

Find the mass of 4.5 moles of H3PO4

Contact [7]

Hey there!

H₃PO₄

Find molar mass.

H: 3 x 1.008 = 3.024

P: 1 x 30.97 = 30.97

O: 4 x 16 = 64

---------------------------------

97.994 grams

The mass of 1 mole of H₃PO₄ is 97.994 grams.

We have 4.5 moles.

97.994 x 4.5 = 440

The mass of 4.5 moles of H₃PO₄ is 440 grams.

Hope this helps!

6 0

3 years ago

Calculate the molarity 20ml of 3.5 m kci in to a final volume of 100 ml

satela [25.4K]

Answer:

Molarity = 0.7 M

Explanation:

Given data:

Volume of KCl = 20 mL ( 0.02 L)

Molarity = 3.5 M

Final volume = 100 mL (0.1 L)

Molarity in 100 mL = ?

Solution:

Molarity = number of moles of solute / volume in litter.

First of all we will determine the number of moles of KCl available.

Number of moles = molarity × volume in litter

Number of moles = 3.5 M × 0.02 L

Number of moles = 0.07 mol

Molarity in 100 mL.

Molarity = number of moles / volume in litter

Molarity = 0.07 mol /0.1 L

Molarity = 0.7 M

3 0

3 years ago

2. When you transfer energy into a substance, the molecules' kinetic energy

GenaCL600 [577]

I don’t! Know bit I guess it’s C

8 0

3 years ago

What is the ph of a solution labeled .30 trimethylamine k for trimethylamine is 7.42 x 10^4

valentina_108 [34]

Answer:the pH is 12

Explanation:

First We need to understand the structure of trimethylamine

Due to the grades of the bond in the nitrogen with a hybridization sp3 is 108° approximately, then is generated a dipole magnetic at the upper side of the nitrogen, this dipole magnetic going to attract a hydrogen molecule of the water making the water more alkaline

C3H9N+ H2O --> C3H9NH + OH-

$k=\frac{[C3H9NH]*[OH-]}{[C3H9N]}$

Then:

The concentration of the trimethylamine is 0.3 and the concentration of the ion C3H9NH is equal to the OH- relying on the stoichiometric equation. We could find the concentration of the OH- ion with the square root of the multiplication between k and the concentration of trimethylamine

[OH-]= $\sqrt{ 0.3*7.42x10^{-4}}$

[OH-]=0.01

pH=14-(-log[OH-])

pH=12

5 0

3 years ago