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3 years ago

How are living things put together?

1 answer:

7 0

D because B is silly, yes we are in groups but that is not how we are put together, Same for reproduction. That is how you're made.

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Is Carbon combustible? Why or why not?

valkas [14]

Carbon is not combustible because when it combines with oxygen its energy increases thus it doesnt combust.

3 0

3 years ago

Please help me! I will fail science if I don’t finish this test :(

Tasya [4]

Answer:

<h2>A. Mercury's orbit is shorter than Earth</h2>

6 0

3 years ago

You determine that it takes 26.0 mL of base to neutralize a sample of your unknown acid solution. The pH of the solution was 7.8

Lubov Fominskaja [6]

Complete Question

You determine that it takes 26.0 mL of base to neutralize a sample of your unknown acid solution. The pH of the solution was 7.82 when exactly 13 mL of base had been added, you notice that the concentration of the unknown acid was 0.1 M. What is the pKa of your unknown acid?

Answer:

The pK_a value is $pK_a =7.82$

Explanation:

From the question we are told

The volume of base is $V_B = 26.mL = 0.0260L$

The pH of solution is $pH = 7.82$

The concentration of the acid is $C_A = 0.1M$

From the pH we can see that the titration is between a strong base and a weak acid

Let assume that the the volume of acid is $V_A = 18mL= 0.018L$

Generally the concentration of base

$C_B = \frac{C_AV_A}{C_B}$

Substituting value

$C_B = \frac{0.1 * 0.01800}{0.0260}$

$C_B= 0.0692M$

When 13mL of the base is added a buffer is formed

The chemical equation of the reaction is

$HA_{(aq)} + OH^-_{(aq)} --------> A^{+}_{(aq)} + H_2 O_{(l)}$

Now before the reaction the number of mole of base is

$No \ of \ moles[N_B] = C_B * V_B$

Substituting value

$N_B = 0.01300 * 0.0692$

$= 0.0009 \ moles$

Now before the reaction the number of mole of acid is

$No \ of \ moles = C_B * V_B$

Substituting value

$N_A = 0.01800 *0.1$

$= 0.001800 \ moles$

Now after the reaction the number of moles of base is zero i.e has been used up

this mathematically represented as

$N_B ' = N_B - N_B = 0$

The number of moles of acid is

$N_A ' = N_A - N_B$

$= 0.0009\ moles$

The pH of this reaction can be mathematically represented as

$pH = pK_a + log \frac{[base]}{[acid]}$

Substituting values

$7.82 = pK_a +log \frac{0.0009}{0.0009}$

$pK_a =7.82$

8 0

3 years ago

Liquid nitrogen is used as a commercial refrigerant to flash freeze foods. Nitrogen boils at

Arisa [49]

77.15 kelvin would be the answer

5 0

2 years ago

Read 2 more answers

What, according to you, are the necessary activities that a penetration tester needs to perform while conducting a penetration t

bogdanovich [222]

Answer: First of all planning is done to set the goals to how to test the target. then scanning is done. after that target is uncovered to see how the target exploits by the use of web application attacks. then analysis is done an tests of the penetration tests are compiled.

Explanation:

6 0

2 years ago