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3 years ago

PLeas hurry

Chemistry

2 answers:

jeka943 years ago

4 0

Construction of dam : scarcity of water for animals

Keith_Richards [23]3 years ago

4 0

Answer:

construction aka A

Explanation:

got 100

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No matter how much water a human drinks, the kidneys are always regulating various aspects of the blood, including _____________

Snowcat [4.5K]

The answers are I, II and IV

No matter how much water a human drinks, the kidneys are always regulating various aspects of the blood, including the pH of the blood, the plasma concentration of iron ions and the plasma concentration of potassium ions.

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3 years ago

Which of the following statements best describes the current atomic theory

Oksana_A [137]

You did not provide the statements but a possible answer might be that the current atomic theory is sound and that technology that could challenge it does not exist at this time. There is no way to change it because no research can be done about it.

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3 years ago

Balance N2 + H2 —NH3 what type of reaction

AnnyKZ [126]

3! You have to ensure balance of all the different elements.

5 0

3 years ago

Question 3) A 1.00 L buffer solution is 0.250 M in HF and 0.250 M in LiF. Calculate the pH of the solution after the addition of

Masja [62]

The pH of the solution after adding 0.150 moles of solid LiF is 3.84

<u>Explanation:</u>

We have the chemical equation,

HF (aq)+NaOH(aq)->NaF(aq)+H2O

To find how many moles have been used in this

c= n/V=> n= c.V

nHF=0.250 M⋅1.5 L=0.375 moles HF

Simillarly

nF=0.250 M⋅1.5 L=0.375 moles F

nHF=0.375 moles - 0.250 moles=0.125 moles

nF=0.375 moles+0.250 moles=0.625 moles

[HF]=0.125 moles/1.5 L=0.0834 M

[F−]=0.625 moles/1.5 L=0.4167 M

To determine the problem using the Henderson - Hasselbalch equation

pH=pKa+log ([conjugate base/[weak acid])

Find the value of Ka

pKa=−log(Ka)

pH=−log(Ka) +log([F−]/[HF]

pH= -log(3.5 x 10 ^4)+log(0.4167 M/0.0834 M)

pH=-log(3.5 x 10 ^4)+log(4.996)

pH= -4.54+0.698

pH=-(-3.84)

pH=3.84

The pH of the solution after adding 0.150 moles of solid LiF is 3.84

5 0

3 years ago

How many moles of helium are 8.84×1024 atoms of He?

insens350 [35]

Answer:

14.68 moles of He

Explanation:

To do this, just remember Avogadro's Constant or Avogadro's number. This constant tells us how many units ( in this case atoms) there are in a mole of ANY type of substance.

Avogadro's constant is 6.022140857 × 10²³ units per mole.

Now that we know how many atoms there are in 1 mole, we can use this as our conversion factor.

8.84 x 10²⁴ atoms of He → moles of He

$8.84\times10^{24} atoms of He\times\dfrac{1moleofHe}{6.022140857\times10^{23}atomsofHe}=14.68molesofHe$

So the answer would be:

14.68 moles of He

4 0

3 years ago