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olya-2409 [2.1K]
3 years ago
9

Which of the following descriptions of gravitational force is NOT TRUE?

Chemistry
1 answer:
tia_tia [17]3 years ago
8 0

Answer:

B

Explanation:

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What happens when hydrogen reacts with nitrogen at necessary conditions.​
Orlov [11]

Answer:

When hydrogen gas combines with nitrogen to form Ammonia the following chemical reaction will take place. Our equilibrium reaction will be N2(g) + 3H2(g) ⇔ 2NH3(g) + Heat. In this case, Hydrogen and nitrogen react together to form ammonia.

Explanation:

3 0
3 years ago
Read 2 more answers
The pKa of lactic acid is 3.9. A lactate buffer will be useful from pH values ________. The pKa of lactic acid is 3.9. A lactate
Vedmedyk [2.9K]

Answer:

Explanation:

The usefulness of a buffer is its ability to resist changes in pH when small quantities of base or acid are added to it. This ability is the consequence of having both the conjugate base and the weak acid present in solution which will consume the added base or acid.  

This capacity is lost if the ratio of the concentration of conjugate base to the concentration of weak acid differ by an order of magnitude. Since  buffers having ratios differing by more will have their pH driven by either the weak acid or its conjugate base .

From the Henderson-Hasselbach equation we have that

pH = pKa + log [A⁻]/[HA]

thus

0.1 ≤  [A⁻]/[HA] ≤ 10

Therefore the log of this range is -1 to 1, and the pH will have a useful range of within +/- 1 the pKa of the buffer.

Now we are equipped to answer our question:

pH range = 3.9 +/- 1 = 2.9 through 4.9

7 0
3 years ago
A student carried out the electrolysis of a KI solution for a period of 15 minutes. He estimated that 8.5 X 10^-4 moles of OH- w
Nataliya [291]

Answer:

Catod: K^(+), H2O

2H2O  + 2e^(-)  ---> H2 + 2OH^(-) reduction reaction

Anod: I^(-), H2O

2I^(-) ---> I2 + 2e^(-) oxidation reduction

2H2O + 2I^(-) ---> I2 + H2 +2OH^(-)   ionic net reaction

6 0
3 years ago
The side chain of histidine has a typical pKa value in the range of 6.5-7.4. However, when analyzing the pKa values in a particu
Leona [35]

Answer:

Statements 1 and 2 are correct.

Explanation:

The microenvironment around a amino acid residue can impact its pKa value according with the Born effect. If there is a positively charged environment, like in the second option, the pKa value will decrease, just as it happens in the histidine residue. So the correct answers are 1 and 2.

8 0
3 years ago
Using the table below, identify the unknown material that has a mass of 15,06 g and a
kati45 [8]

The unknown material : gold

<h3>Further explanation  </h3>

Density is a quantity derived from the mass and volume  

Density is the ratio of mass per unit volume  

Density formula:  

\large {\boxed {\bold {\rho ~ = ~ \frac {m} {V}}}}

ρ = density  

m = mass  

v = volume  

mass of unknown the material : 15.06 g

volume = 0.78 ml

The density :

\tt \rho=\dfrac{m}{V}\\\\\rho=\dfrac{15.06}{0.78}=19.31~g/ml

materials that match the density: gold

8 0
3 years ago
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