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3 years ago

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Chemistry

1 answer:

wariber [46]3 years ago

7 0

Answer:

The reaction is endothermic

Explanation:

we know that the reactants had to get energy from its surroundings which means that the reaction is endothermic

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All the substances listed below are fertilizers that contribute nitrogen to the soil.

kvv77 [185]

Answer:

Ammonia is the richest source of nitrogen on a mass percentage basis because it has 82.35% of nitrogen by mass.

Explanation:

Percentage of element in compound :

$=\frac{\text{number of atoms}\times text{Atomic mass}}{\text{molar mas of compound}}\times 100$

(a) Urea, $(NH_2)_2CO$

Molar mass of urea = 60 g/mol

Atomic mass of nitrogen = 14 g/mol

Number of nitrogen atoms = 2

$N\%=\frac{2\times 14 g/mol}{60 g/mol}\times 100=46.67\%$

(b) Ammonium nitrate, $NH_4NO_3$

Molar mass of ammonium nitrate = 80 g/mol

Atomic mass of nitrogen = 14 g/mol

Number of nitrogen atoms = 2

$N\%=\frac{2\times 14 g/mol}{80 g/mol}\times 100=35.00\%$

(c) Nitric oxide, NO

Molar mass of nitric oxide = 30 g/mol

Atomic mass of nitrogen = 14 g/mol

Number of nitrogen atoms = 1

$N\%=\frac{1\times 14 g/mol}{30 g/mol}\times 100=46.67\%$

(d) Ammonia, $NH_3$

Molar mass of ammona = 17 g/mol

Atomic mass of nitrogen = 14 g/mol

Number of nitrogen atoms = 1

$N\%=\frac{1\times 14 g/mol}{17 g/mol}\times 100=82.35\%$

Ammonia is the richest source of nitrogen on a mass percentage basis because it has 82.35% of nitrogen by mass.

4 0

3 years ago

Which intermolecular force would affect melting point the most?

Anastaziya [24]

Answer:

Hydrogen bonding

Explanation:

3 0

3 years ago

What element has a mass number of 138 and protons equal to 57?

Murljashka [212]

Basic Information
Name: Lanthanum 
Symbol: La 
Atomic Number: 57 
Atomic Mass: 138.9055 amu 
Melting Point: 920.0 °C (1193.15 K, 1688.0 °F) 
Boiling Point: 3469.0 °C (3742.15 K, 6276.2 °F) 
Number of Protons/Electrons: 57 
Number of Neutrons: 82 
Classification: Rare Earth
Crystal Structure: Hexagonal 
Density @ 293 K: 6.7 g/cm3
Color: white

6 0

3 years ago

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Draw the zaitsev product formed when 2,3-dimethylpentan-3-ol undergoes an e1 dehydration.

mihalych1998 [28]

Answer: ince 2,4-dimethylpentan-3-ol is symmetrical there will only be one product formed after dehydration. It is 2,4-dimethyl-2-pentene

8 0

3 years ago

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A student performs a chemical reaction with vinegar and an antacid tablet. Experimental results are displayed in the table

Georgia [21]

Answer:

Explanation:

Please tell me if im wrong

Question 6. 6. In a reaction between vinegar and antacid tablets, the antacid is the limiting reagent. At constant pressure and temperature, three tablets produce 600 cm3 of gas. What volume will two tablets produce?

(Points : 3)

400 cm3

600 cm3

800 cm3

1,200 cm3****

Question 7. 7. You breathe in 3.0 L of pure oxygen at 298 K and 1,000 kPa. How many moles of oxygen did you take in? (Use the ideal gas law: PV = nRT where R = 8.31 L-kPa/mol-K.)

(Points : 3)

0.05 moles

1.21 moles*****

2.42 moles

20.0 moles

Question 8. 8. Consider a gas at STP in a container of 22.4 L. If you apply the ideal gas law, what is the approximate value of n?

(Points : 3)

0.5

8.31

224****

Question 9. 9. Water boils at 100°C. What is that temperature on the Kelvin scale?

(Points : 3)

213 K

325 K****

333 K

373 K

Question 10. 10. The average speeds of gas molecules in cylinders A, B, C, and D are 0.001 m/s, 0.05 m/s, 0.1 m/s, and 0.5 m/s, respectively. Which cylinder contains gas that is closest to absolute zero?

(Points : 3)

C******

I suck at chemistry

4 0

3 years ago