All categories

3 years ago

What type of reaction is: CaO + H2O -> Ca(OH)2? A. Combustion B. Synthesis C. Double Replacement D. Decomposition

Chemistry

1 answer:

12345 [234]3 years ago

8 0

Answer:

The reaction is B. Synthesis

Explanation:

In the case of this reaction, it corresponds to a synthesis where 2 compounds (calcium oxide and water) are combined to form a new one (calcium hydroxide).

You might be interested in

Oxygen gas can be prepared by heating potassium chlorate according to the following equation: 2KClO3(s)2KCl(s) + 3O2(g) The prod

Ipatiy [6.2K]

Answer:

The number of moles of KClO₃ reacted was 0,15 mol

Explanation:

For the reaction:

2KClO₃(s) → 2KCl(s) + 2O₂(g)

The only gas product is O₂.

Total pressure is the sum of vapor pressure of water with O₂ gas formed. Thus, pressure of O₂ is:

749mmHg - 23,8mmHg = 725,2mmHg

Using gas law:

PV/RT = n

Where:

P is pressure (725,2mmHg ≡ 0,9542atm)

V is volume (5,76L)

R is gas constant (0,082 atmL/molK)

And T is temperature (25°C ≡ 298,15K)

Replacing, number of moles of O₂ are 0,2248 moles

As 2 moles of KClO₃ react with 3 moles of O₂ the moles of KClO₃ that reacted was:

0,2248 mol O₂× $\frac{2 mol KClO_{3}}{3 mol O_{2}}$ = 0,15 mol of KClO₃

I hope it helps!

8 0

3 years ago

In a coffee-cup calorimeter, 100.0 g of H2O and 8.70 grams of Na3PO4 are added. The water had an initial temperature of 24.6 oC.

Alex

Answer:

a.) exothermic

b.) 2,800.6 J

Explanation:

3 0

2 years ago

What elements comprise the largest portion of Earth's atmosphere?

Mrrafil [7]

Answer:

Nitrogen and Oxygen make up 99% of the Earths atmosphere. Then Argon makes up the rest of the atmosphere.

3 0

2 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

pH = 10.05

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 = 0.20

I hope it helps!

3 0

2 years ago

When the reaction mixture is worked-up, it is first washed three times with 5% sodium bicarbonate, and then with a saturated nac

Ann [662]

Solution:

After the reaction of mixture is worked-up Washing three times the organic with sodium carbonate helps to decrease the solubility of the organic layer into the aqueous layer. This allows the organic layer to be separated more easily.

And then the reaction washed by saturated NACL we have The bulk of the water can often be removed by shaking or "washing" the organic layer with saturated aqueous sodium chloride (otherwise known as brine). The salt water works to pull the water from the organic layer to the water layer.

5 0

3 years ago