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3 years ago

A chemical change takes place when

Chemistry

2 answers:

navik [9.2K]3 years ago

7 0

Answer:

2 ways in which a weather satellite can orbit the earth

Explanation:

Mama L [17]3 years ago

6 0

Answer:

Explanation:

the substance is being changed

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Indicate which molecules demonstrate the correct bonding for carbon atoms. Check all that apply.

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Answer:

CH4 and CH3 CH2 CH2 CH3

Explanation:

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Which of the following is correct concerning subatomic particles?

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The following answers:
1. B
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3 years ago

Ammonia (NH3) is one of the most common chemicals produced in the united states. it is used to make fertilizer and other product

Greeley [361]

Answer:

a) N2 is the limiting reactant

b) 1215.9 grams NH3

c) 2283.6 grams H2

Explanation:

Step 1: Data given

Mass of N2 = 1000 grams

Molar mass N2 = 28 g/mol

Mass of H2 = 2500 grams

Molar mass H2 = 2.02 g/mol

Step 2: The balanced equation

N2(g) +3H2(g) → 2NH3(g)

Step 3: Calculate moles N2

Moles N2 = mass N2 / molar mass N2

Moles N2 = 1000 grams / 28.0 g/mol

Moles N2 = 35.7 moles

Step 4: Calculate moles H2

Moles H2 = 2500 grams / 2.02 g/mol

Moles H2 = 1237.6 moles

Step 5: Calculate limiting reactant

For 1 mol N2 we need 3 moles H2 to produce 2 moles NH3

N2 is the limiting reactant. There will be consumed 35.7 moles.

H2 is in excess. There will react 3*35.7 = 107.1 moles

There will remain 1237.6 - 107.1= 1130.5 moles H2

This is 1130.5 * 2.2 = 2283.6 grams H2

Step 6: Calculate moles NH3

For 1 mol N2 we need 3 moles H2 to produce 2 moles NH3

For 35.7 moles N2 we'll have 2*35.7 = 71.4 moles NH3

Step 7: Calculate mass NH3

Mass NH3 = moles NH3 * molar mass NH3

Mass NH3 = 71.4 moles * 17.03 g/mol

Mass NH3 = 1215.9 grams NH3

7 0

3 years ago

Please help! Thanks!

olya-2409 [2.1K]

Answer:

The deviations are :

The activation energy which changes with temperature
The arrhenius constant which depends on the temperature

Explanation:

There are deviations from the Arrhenius law during the glass transition in all classes of glass-forming matter.

The Arrhenius law predicts that the motion of the structural units (atoms, molecules, ions, etc.) should slow down at a slower rate through the glass transition than is experimentally observed.
In other words, the structural units slow down at a faster rate than is predicted by the Arrhenius law.
This observation is made reasonable assuming that the units must overcome an energy barrier by means of a thermal activation energy.
The thermal energy must be high enough to allow for translational motion of the units which leads to viscous flow of the material.

Both the Arrhenius activation energy and the rate constant k are experimentally determined, and represent macroscopic reaction-specific parameters that are not simply related to threshold energies and the success of individual collisions at the molecular level.
Consider a particular collision (an elementary reaction) between molecules A and B. The collision angle, the relative translational energy, the internal (particularly vibrational) energy will all determine the chance that the collision will produce a product molecule AB.
Macroscopic measurements of E(activation energy) and k(rate constant ) are the result of many individual collisions with differing collision parameters. They are averaged out to a macroscopic quantity.

6 0

3 years ago