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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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Katyanochek1 [597]

Answer:

The answer to your question is     V2 = 4.97 l

Explanation:

Data

Volume 1 = V1 = 4.40 L                    Volume 2 =

Temperature 1 = T1 = 19°C               Temperature 2 = T2 = 37°C

Pressure 1 = P1 = 783 mmHg           Pressure 2 = 735 mmHg

Process

1.- Convert temperature to °K

T1 = 19 + 273 = 292°K

T2 = 37 + 273 = 310°K

2.- Use the combined gas law to solve this problem

                  P1V1/T1  = P2V2/T2

-Solve for V2

                  V2 = P1V1T2 / T1P2

-Substitution

                  V2 = (783 x 4.40 x 310) / (292 x 735)

-Simplification

                 V2 = 1068012 / 214620

-Result

                 V2 = 4.97 l

6 0
3 years ago
What is the contrast of these two atoms?
Katena32 [7]

Answer:

The atomic number of silicon is 14 while atomic mass of carbon is 14.

Explanation:

An atom consist of electron, protons and neutrons. Protons and neutrons are present with in nucleus while the electrons are present out side the nucleus.

All these three subatomic particles construct an atom. A neutral atom have equal number of proton and electron. In other words we can say that negative and positive charges are equal in magnitude and cancel the each other. For example if neutral atom has 6 protons than it must have 6 electrons. The sum of neutrons and protons is the mass number of an atom while the number of protons are number of electrons is the atomic number of an atom.

In given atoms ¹⁴₆C  and ²⁸₁₄Si the atomic mass of carbon is 14 while the atomic number of silicon is 14. It means silicon has 14 electrons or protons while carbon has 6 protons or electrons because its atomic number is 6. Carbon has 6 protons and 8 neutrons in its nucleus while silicon has 14 protons and 14 neutrons in its nucleus.

In C:

Number of neutrons + protons = 8 + 6 = 14 amu (mass number)

Number of electrons = 6

In Si:

Number of neutrons + protons = 14 + 14 = 28 amu (mass number)

Number of electrons = 14

6 0
4 years ago
HURRY PLEASE!!
Alexandra [31]
From what i can gather it looks like d 

5 0
3 years ago
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Atomic size generally _____.
Lunna [17]
A. Increases as you move from left to right across a period
4 0
3 years ago
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When heating a sample to extreme heat over a flame, you will often use a crucible. Before starting the heating, you should locat
Ghella [55]

Answer:

The equipments you should have ready to start the crucible experiment includes: safety goggles, crucible with lid, crucible tong, ring support with clay triangle, Bunsen burner and heat resistant tile.

Explanation:

Crucible is an equipment in the laboratory which is suitable for heating a sample to extreme heat over a flame, Modern laboratory crucible are made up of graphite- based composite materials for achievement of higher performance. Because extreme heat is involved, you should locate the correct labware for the experiment, including the equipment to safely handle and support the crucible. These equipments includes:

--> Safety goggles: Because you will work with chemical it is advisable to use a safety goggles which protects the eyes from dangerous floating chemical aerosol.

--> crucible with lid: This is the main apparatus with the lid (cover) which is used to cover the crucible to prevent spilling of the boiling chemical.

--> Crucible tong: These are scissors like tools used to grasp hot crucible.

--> Ring support with clay triangle: the clay triangle is used to hold crucible when they are being heated. They usually sit on a ring stand.

--> Bunsen burner: Produces a single open gas flame which can be used for heating.

With the safety equipments listed above, you can carry out experiment using the crucible. These equipments helps minimise laboratory hazard that may occur should Incase it's not available.

6 0
3 years ago
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