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mamaluj [8]
3 years ago
14

I NEED HELP PLEASE, THANKS! :)

Chemistry
1 answer:
Leto [7]3 years ago
8 0

Answer:

Here's what I get  

Explanation:

i. E = mc²

E = energy

m = mass

c = the speed of light

"Energy equals mass times the square of the speed of light.”

The equation says that energy and mass are interchangeable. If you multiply the mass of an object by c², you get its equivalent and of energy.

The SI base units for energy are kg·m²s⁻².  

The most common derived unit is the joule (J). Others are the newton-metre (N·m), kilowatt-hour (kWh), watt-second (W·s), and volt-coulomb (V·C).

ii. Nuclear vs chemical reactions

a. Alpha decay

\rm _{92}^{238}\text{U} \longrightarrow \,  _{2}^{4}\text{He} + \, _{90}^{234}\text{Th}

A nuclear reaction — like α decay — takes place in the nucleus of an atom.

An element becomes a different element.

b. Chemical reaction

Na· + ·Cl ⟶ Na⁺ + Cl⁻

A chemical reaction — like the formation of NaCl — involves rearranging the electrons, which are outside the nucleus.

The elements do not change.

Salt still consists of sodium and chlorine.

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Hey just say that the water carrys sediment to different places by it current if i put sand in a stream it will go down it 

8 0
3 years ago
Equal volumes of two solutions, one containing a strong acid at pH 2 and the other containing a strong base at pH 12, are mixed.
mash [69]

Answer:

7  

Explanation:

Assume we have 1 L of each solution.

Solution 1

\text{[H$^{+}$]}= 10^\text{-pH} \text{ mol/L} = 10^{\text{-2}} \text{ mol/L}\\ \text{ moles of H}^{+} = \text{ 1 L solution} \times \dfrac{10^{-2}\text{ mol H}^{+}}{\text{1 L solution}} = 10^{-2}\text{ mol H}^{+}

Solution 2

pH = 12

pOH = 14.00 - pOH = 14.00 - 12 = 2.0

\text{[OH$^{-}$]}= 10^\text{-pOH} \text{ mol/L} = 10^{\text{-2}} \text{ mol/L}\\ \text{ moles of OH}^{-} = \text{ 1 L solution} \times \dfrac{10^{-2}\text{ mol OH}^{-}}{\text{1 L solution}} = 10^{-2}\text{ mol OH}^{-}

3. pH after mixing

               H⁺  +  OH⁻ ⟶ H₂O

I/mol:     10⁻²    10⁻²  

C/mol:   -10⁻²   -10⁻²

E/mol:      0        0

The H⁺ and OH⁻ have neutralized each other. The pH will be that of pure water.

pH = 7

8 0
3 years ago
An aqueous solution of 1.29 M ethanol, CH3CH2OH, has a density of 0.988 g/mL. The percent by mass of CH3CH2OH in the solution is
anzhelika [568]

Answer:

6%

Explanation:

Hello, for this case, we assume that the volume of the solution is 1L, thus, the mass is given by using the density as follows:

m_{solution}=1L*\frac{1000 mL}{1L}*\frac{0.988g}{1mL} =988g

Now, the mass of the ethanol:

m_{C_2H_5OH}=(1.29molC_2H_5OH/L*1L)*\frac{46gC_2H_5OH}{1molC_2H_5OH} \\m_{C_2H_5OH}=59.34g

Finally, the by mass percent is:

m/m=\frac{59.34g}{988g}*100\\%

%m=6%

Best regards.

4 0
3 years ago
What is disproportionation reaction and give one example of it ?​
mario62 [17]

Answer:

A disproportionation reaction is when a multiatomic species whose pertinent element has a specific oxidation state gets oxidized and reduced in two separate half-reactions, yielding two other products containing the same pertinent element. A convenient example is Mn2O3 becoming Mn2+ and MnO2 .

4 0
3 years ago
Read 2 more answers
Help please hurry pic below
masha68 [24]

Answer:

Hi

Explanation:

5 0
3 years ago
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