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Mrrafil [7]
4 years ago
15

choose the reaction that illustrates delta H *f for Ca(NO3)2.(A) Ca (s) + N2 (g) + 3O2 ---> Ca(NO3)2 (s)(B) Ca2 (aq) + 2 NO3-

(aq) ---> Ca(NO3)2 (aq)(C) Ca (s) + 2N (g) + 6O (g) ---> Ca(NO3)2 (s)(D) Ca(NO3)2 (aq) ---> Ca2+ (aq) + 2NO3- (aq)(E) Ca(NO3)2 (s) ---> Ca(s) + N2 (g) + 3 O2 (g)
Chemistry
1 answer:
kompoz [17]4 years ago
3 0

<u>Answer:</u> The correct answer is Option A.

<u>Explanation:</u>

Standard enthalpy of formation is the change in enthalpy of  one mole of a substance present at the standard state that is 1 atm of pressure and 298 K of temperature. The substance is formed from its pure elements under the same conditions.

We are given a chemical compound having chemical formula Ca(NO_3)_2

This compound is formed by the combination of calcium, nitrogen and oxygen elements.

The chemical equation for the formation of Ca(NO_3)_2 from the components in their standard states follows:

Ca+N_2+3O_2\rightarrow Ca(NO_3)_3

Hence, the correct answer is Option A.

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A small 23 kilogram canoe is floating downriver at a speed of 3 m/s. What is the canoe's kinetic energy?
Ivanshal [37]

Kinetic energy is defined as the energy the object possess due to its motion. It is the work that accelerates a given body from rest to motion.

Given:

The mass of the canoe is 23 kilogram

The velocity of the canoe is 3 m/s

The kinetic energy can be given by the formula:

KE = \frac{1}{2}.m.v^{2}

Substituting the given values in the kinetic energy equation

KE =\frac{1}{2}.(23kg).(3m/s)^{2}

KE= 11.5 * 9 kg.m^2/s^2

k = 103.5 J

Therefore the kinetic energy of the canoe is 103.5 Joules.

3 0
3 years ago
When an ice cube melts it is still water
Leto [7]

Answer:

yes it is still water

Explanation:

4 0
3 years ago
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One reason ionic compounds do not dissolve well in nonpolar solvents is that ___.
Lapatulllka [165]

Answer:

d. there are no forces of attraction between ions and nonpolar molecules.

Explanation:

Solubility is determined by the principle , "like dissolves like" .

i.e. , if a compound is polar then it will dissolve in a polar compound only , and

if a compound is non - polar then it will dissolve in a non - polar compound only .

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6 0
3 years ago
35g of HF was prepared by reacting 112g of CaF2 with an excess of H2SO4 calculate the percentage yield
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Answer: 61%


The reaction equation should be

CaF2 + H2SO4 → 2HF + CaSO4

For every 1 molecule CaF2 used, there will be 2 molecules of HF formed. The molecular mass of CaF2 is 78/mol while the molecular mass of HF is 20g/mol. If the yield is 100%, the amount of HF formed by 112g CaF2 would be: 112g/(78g/mol) * 2 * (20g/mol)=57.43g

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