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3 years ago

If a decrease in temperature accompanies a reaction, what occurred?

Chemistry

2 answers:

marusya05 [52]3 years ago

8 0

Released my friending

AleksAgata [21]3 years ago

3 0

Energy was released

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Please help ASAP!! (I added a pic)

riadik2000 [5.3K]

The middle is noble gases the first one is alkaline metals and then the last one is the only one left

4 0

3 years ago

Jacques Charles used this reaction to prepare hydrogen gas for his historic balloon flights: Fe(s) + H2SO4(aq) = FeSO4(aq) + H2(

alekssr [168]

Answer:

Volume = 98.5 L.

Explanation:

Below are attachments containing the solution

4 0

3 years ago

A buffer solution contains 0.306 M C6H5NH3Br and 0.418 M C6H5NH2 (aniline). Determine the pH change when 0.124 mol HCl is added

Ulleksa [173]

Answer: The pH change of the buffer is 0.30

Explanation:

To calculate the pH of basic buffer, we use the equation given by Henderson Hasselbalch:

$pOH=pK_b+\log(\frac{[\text{conjugate acid}]}{[\text{base}]})$

$pOH=pK_b+\log(\frac{[C_6H_5NH_3^+]}{[C_6H_5NH_2]})$ .....(1)

We are given:

$pK_b$ = negative logarithm of base dissociation constant of aniline = 9.13

$[C_6H_5NH_3^+]=0.306M$

$[C_6H_5NH_2]=0.418M$

pOH = ?

Putting values in equation 1, we get:

$pOH=9.13+\log(\frac{0.306}{0.418})\\\\pOH=8.99$

To calculate pH of the solution, we use the equation:

$pH+pOH=14\\pH_{initial}=14-8.99=5.01$

To calculate the molarity, we use the equation:

$\text{Molarity of the solution}=\frac{\text{Moles of solute}}{\text{Volume of solution (in L)}}$

Moles hydrochloric acid solution = 0.124 mol

Volume of solution = 1 L

Putting values in above equation, we get:

$\text{Molarity of HCl}=\frac{0.124}{1L}\\\\\text{Molarity of HCl}=0.124M$

The chemical reaction for aniline and HCl follows the equation:

$C_6H_5NH_2+HCl\rightarrow C_6H_5NH_3^++Cl^-$

Initial: 0.418 0.124 0.306

Final: 0.294 - 0.430

Calculating the pOH by using using equation 1:

$pK_b$ = negative logarithm of base dissociation constant of aniline = 9.13

$[C_6H_5NH_3^+]=0.430M$

$[C_6H_5NH_2]=0.294M$

pOH = ?

Putting values in equation 1, we get:

$pOH=9.13+\log(\frac{0.430}{0.294})\\\\pOH=9.29$

To calculate pH of the solution, we use the equation:

$pH+pOH=14\\pH_{final}=14-9.29=4.71$

Calculating the pH change of the solution:

$\Delta pH=pH_{initial}-pH_{final}\\\\\Delta pH=5.01-4.71=0.30$

Hence, the pH change of the buffer is 0.30

8 0

3 years ago

The sun is 150 kilometers from earth.if you wanted to explain to friend how far is what would you say

jasenka [17]

Answer:

150 times 1000 is how many meters it is away from earth because kilo means 1000

Explanation:

easy metric conversions

5 0

3 years ago

Why is the melting point of a network solid so high? How is this related to what a network solid is?

Alexxandr [17]

I believe that the answer to the question provided above is that molecules in solid are compact and are connected. It requires huge energy to move it, thus requires high temperature.
Hope my answer would be a great help for you. If you have more questions feel free to ask here at Brainly.

4 0

3 years ago