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melomori [17]
3 years ago
5

What is an echo? (1 point)

Chemistry
2 answers:
makvit [3.9K]3 years ago
6 0
The reflection of sound waves, hope this helps :)
zaharov [31]3 years ago
4 0

Answer:

The reflection of sound waves

Explanation:

An echo is a reflection of sound that bounces of of one thing to another.

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What is the most common way atoms combine
Semenov [28]
Atoms combine<span> by forming chemical bonds</span>
4 0
3 years ago
PLZZZZZZZZZZZZZZZZZZ15. As much as 90 percent of the oxygen in our atmosphere is the result of
vladimir2022 [97]

Answer:

The correct answer is - option D. photosynthesis.

Explanation:

It is shown by the study that most of the atmospheric oxygen comes from the photosynthesis by plants as oxygen is the byproduct of the photosynthesis. Photosynthesis is the process that uses light energy, carbon dioxide, and water to produce food or glucose/sugar and release oxygen as the byproduct.

Many scientists believe that oceanic phytoplankton that releases oxygen by the photosynthesis process makes 80 to 85% of the total oxygen of the atmospheric oxygen.

7 0
3 years ago
Read 2 more answers
A 5.024 mg sample of an unknown organic molecule containing carbon, hydrogen, and nitrogen only was burned and yielded 13.90 mg
Dafna1 [17]

Answer:

C8H17N

Explanation:

Mass of the unknown compound = 5.024 mg

Mass of CO2 = 13.90 mg

Mass of H2O = 6.048 mg

Next, we shall determine the mass of carbon, hydrogen and nitrogen present in the compound. This is illustrated below:

For carbon, C:

Molar mass of CO2 = 12 + (2x16) = 44g/mol

Mass of C = 12/44 x 13.90 = 3.791 mg

For hydrogen, H:

Molar mass of H2O = (2x1) + 16 = 18g/mol

Mass of H = 2/18 x 6.048 = 0.672 mg

For nitrogen, N:

Mass N = mass of unknown – (mass of C + mass of H)

Mass of N = 5.024 – (3.791 + 0.672)

Mass of N = 0.561 mg

Now, we can obtain the empirical formula for the compound as follow:

C = 3.791 mg

H = 0.672 mg

N = 0.561 mg

Divide each by their molar mass

C = 3.791 / 12 = 0.316

H = 0.672 / 1 = 0.672

N = 0.561 / 14 = 0.040

Divide by the smallest

C = 0.316 / 0.04 = 8

H = 0.672 / 0.04 = 17

N = 0.040 / 0.04 = 1

Therefore, the empirical formula for the compound is C8H17N

8 0
3 years ago
Gr6_Sci_Assesment\FY18
Rzqust [24]

Answer:

A. The student did not include the effect of friction in his calculation.

Explanation:

They are not equal because kinetic energy is relative to the state of other objects in its environment such as friction which doesn't apply to potential energy.

5 0
3 years ago
Estimate ΔG°rxn for the following reaction at 775 K. 2Hg(g) + O2(g) → 2HgO(s) ΔH°= -304.2 kJ; ΔS° = -414.2 J/K
hichkok12 [17]

Answer:

\Delta G^0_{rxn}=16.81kJ

Explanation:

Hello!

In this case, since the Gibbs free energy of any process is related with the enthalpy change, temperature and entropy change as shown below:

\Delta G^0=\Delta H^0-T\Delta S^0

For a chemical reaction it is simply modified to:

\Delta G^0_{rxn}=\Delta H^0_{rxn}-T\Delta S^0_{rxn}

Thus, since the enthalpy of reaction is given as -304.2 kJ and the entropy as -414.2 J/K (-0.4142 kJ/K), at 775 K the Gibbs free energy of reaction turns out:

\Delta G^0_{rxn}=-304kJ-775K*(-0.4142\frac{kJ}{K} )\\\\\Delta G^0_{rxn}=16.81kJ

Whose result means this is a nonspontaneous reaction.

Best regards!

3 0
3 years ago
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