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Vesna [10]
3 years ago
14

PLEASE HELP ME !!!

Chemistry
1 answer:
kari74 [83]3 years ago
3 0

Answer:

c, often , fossil remains of a large complex animal are incomplete

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A 15.00-ml sample of a naoh solution of unknown concentration requires 17.88 ml of a 0.1053 m h2so4 solution to reach the equiva
Sergeu [11.5K]

Answer:

  • <u>0.1255 M</u>

Explanation:

<u>1) Data:</u>

Base: NaOH

Vb = 15.00 ml = 15.00 / 1,000 liter

Mb = ?

Acid: H₂SO₄

Va = 17.88 ml = 17.88 / 1,000 liter

Ma = 0.1053

<u>2) Chemical reaction:</u>

The <em>titration</em> is an acid-base (neutralization) reaction to yield a salt and water:

  • Acid + Base → Salt + Water

  • H₂SO₄ (aq) + NaOH(aq) → Na₂SO₄ (aq) + H₂O (l)

<u>3) Balanced chemical equation:</u>

  • H₂SO₄ (aq) + 2 NaOH(aq) → Na₂SO₄ (aq) + 2H₂O (l)

Placing coefficient 2 in front of NaOH and H₂O balances the equation

<u>4) Stoichiometric mole ratio:</u>

The coefficients of the balanced chemical equation show that 1 mole of H₂SO₄ react with 2 moles of NaOH. Hence, the mole ratio is:

  • 1 mole H₂SO₄ : 2 mole NaOH

<u>5) Calculations:</u>

a) Molarity formula: M = n / V (in liter)

   ⇒ n = M × V

b) Nunber of moles of acid:

  • nₐ = Ma × Va = 0.1053 (17.88 / 1,000)

c) Number of moles of base, nb:

  • nb = Mb × Vb = Mb × (15.00 / 1,000)

d) At equivalence point number of moles of acid = number of moles of base

  • nₐ = nb

  • 0.1053 × (17.88 / 1,000) =  Mb × (15.00 / 1,000)

  • Mb = 0.1053 × 17.88  / 15.00 = 0.1255 mole/liter = 0.1255 M
3 0
3 years ago
Read 2 more answers
Calculate the mole fraction of the total ions in an aqueous solution prepared by dissolving 0.400 moles of CaI2 in 850.0 g of wa
Evgesh-ka [11]

Answer:

0.00840

Explanation:

The computation of the mole fraction is as follow:

As we know that

Molar mass = Number of grams ÷ number of moles

Or

number of moles = Number of grams ÷ molar mass

Given that

Number of moles of CaI2 = 0.400

And, Molar mass of water = 18.0 g/mol

Now  Number of moles of water is

= 850.0 g ÷ 18.0 g/mol

= 47.22 mol

And, Total number of moles is

= 0.400 + 47.22

= 47.62

So, Molar fraction of CaI2 is

= 0.400 ÷ 47.62

= 0.00840

4 0
3 years ago
When one form of energy is converted to another form in any physical or chemical change, energy input alwasy equals energy outpu
aliya0001 [1]
In the context of chemistry, yes. Energy input is always equal to the energy output.
5 0
2 years ago
Explain why current flowing indicates the presence of ions
seraphim [82]

Explanation:

An electron current, the flow of electrons, contributes to an electric current since the electron 'carries' negative electric charge. ... The flow of ions (either positively or negatively charged) also contributes to an electric current in, for example, the electrolyte of an electrochemical cell.

hope it will work well?!

3 0
2 years ago
If i have an 86 and i don’t do a 50 point assignment, what will my grade be in the class?
nexus9112 [7]
Well you are at a 86% so t<span>his is considered a "B" grade on an average grade scale. If you take 50 points we would need to know the Total point you could have got in that class to be able to see how much a percent was the assignment work and then take that percentage of the assignment and subtract it from the 86% to see where on the scale you would fall in after the assignment points were taken off.   Hope this helps :)
</span>
7 0
2 years ago
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