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kramer
3 years ago
15

Son el punto 2,3,4 por favor

Chemistry
1 answer:
RSB [31]3 years ago
8 0
4...........................
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Which property of fossil fuel make them an important resource for life on earth
grandymaker [24]

Fossil Fuels give off energy when they are burned

One valuable fossil fuel is natural gas.  It is a cleaner-burning fuel source.

7 0
3 years ago
12.5 mL of 0.280 M HNO3 and 5.0 mL of 0.920 M KOH are mixed. Is the resulting solution acidic, basic or neutral?
svlad2 [7]

Answer:

The resulting solution is basic.

Explanation:

The reaction that takes place is:

  • HNO₃ + KOH → KNO₃ + H₂O

First we <u>calculate the added moles of HNO₃ and KOH</u>:

  • HNO₃ ⇒ 12.5 mL * 0.280 M = 3.5 mmol HNO₃
  • KOH ⇒ 5.0 mL * 0.920 M = 4.6 mmol KOH

As <em>there are more KOH moles than HNO₃,</em> the resulting solution is basic.

8 0
3 years ago
A buffer solution contains 0.479 M NaHCO3 and 0.342 M Na2CO3. Determine the pH change when 0.091 mol HNO3 is added to 1.00 L of
pshichka [43]

Answer:

ΔpH = 0.20

Explanation:

The buffer of HCO₃⁻ + CO₃²⁻ has a pka of 10.2

HCO₃⁻ ⇄ H⁺ + CO₃²⁻

There are 0.479moles of NaHCO₃ and 0.342moles of Na₂CO₃.

Using Henderson-Hasselbalch formula:

pH = pka + log [Base] / [Acid]

pH = 10.2 + log 0.342mol / 0.479mol

<em>pH = 10.05</em>

NaOH reacts with HCO₃⁻ producing CO₃²⁻, thus:

NaOH + HCO₃⁻ → CO₃²⁻ + H₂O + Na⁺

0.091 moles of NaOH produce the same moles of CO₃²⁻ and consume HCO₃⁻. Moles of these species are:

CO₃²⁻: 0.342mol + 0.091mol: 0.433mol

HCO₃⁻: 0.479mol - 0.091 mol: 0.388mol

Using Henderson-Hasselbalch formula:

pH = pka + log [Base] / [Acid]

pH = 10.2 + log 0.433mol / 0.388mol

pH = 10.25

That means change of pH, ΔpH is:

ΔpH = 10.25 - 10.05 = <em>0.20</em>

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I hope it helps!

3 0
3 years ago
If we start with 20 atoms of plutonium – 239, how many would remain after 48,240 years?
Zepler [3.9K]

Answer:

If we start with 20 atoms of plutonium – 239, how many would remain after 48,240 years?

Explanation:

So, before we are going to tackle this topic, I would discuss how to remain it as soon as possible. Like this, go to the site with so many answers to be seen. So m SC ndkz ek Afe sifrhidbjdjwsb in free jdbsjjkn WA jdj ew

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Someone help me please. It's due in 30 mins
max2010maxim [7]

Answer: permanent removal of hair by energy or heat

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