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2 years ago

The enthalpy of formation of water is –285.8 kJ/mol. What can be inferred from this statement?

Chemistry

2 answers:

LiRa [457]2 years ago

4 0

A negative formation enthalpy means that the reaction is exothermic, or that heat is released during the process.
(C,)

Klio2033 [76]2 years ago

3 0

The negative enthalpy of formation of water infers that heat is released during the process.

Answer: Option C

Explanation:

Enthalpy is the measure of internal energy of the system with pressure and volume. And Enthalpy of formations are the measure of change in enthalpy occurred during the formation of products from its elements.

The enthalpy of formation can be defined as the change in enthalpy required to form 1 mole of products from its element. Thus it can be either negative value or positive value. So if the enthalpy of formation is negative that means the heat is released during the process.

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A 2.20 g sample of a compound gave 5.63 g CO2 and 2.30 g H2O on combustion in air. The compound is known to contain only C, H, O

ICE Princess25 [194]

The simplest formula is C₅H₁₀O.

We must calculate the masses of C, H, and O from the masses given.

Mass of C =5.63 g CO₂ × (12.01 g C/44.01 g CO₂) = 1.536 g C

Mass of H = 2.30 g H₂O × (2.016 g H/18.02 g H₂O) = 0.2573 g H

Mass of O = Mass of compound - Mass of C - Mass of H

= (2.20 – 1.536 – 0.2573) g = 0.406 g

Now, we must convert these masses to moles and find their ratios.

From here on, I like to summarize the calculations in a table.

Element Mass/g Moles Ratio Integers

C 1.536 0.1279 5.038 5

H 0.2573 0.2553 10.05 10

O 0.406 0.0254 1 1

The empirical formula is C₅H₁₀O.

7 0

2 years ago

Among these processes, which is the slowest chemical reaction?

user100 [1]

After some thinking I have come to the conclusion that the answer is C.

8 0

2 years ago

Read 2 more answers

If 25.0 g of NH₃ and 45.0g of O₂ react in the following reaction, what is the mass in grams of NO that will be formed? 4 NH₃ (g)

Allisa [31]

Answer:

The correct answer would be : 33.8 g

Explanation:

Molar mass of ammonia,

Molar Mass = 1* Molar Mass(N) + 3* Molar Mass (H)

= 1*14.01 + 3*1.008 = 17.034 g/mol

mass(NH3)= 25.0 g (given)

number of mol of NH3,

n = mass of NH3/molar mass of NH3

=(25.0 g)/(17.034 g/mol)

= 1.468 mol

Now,

Molar mass of O2

= 32 g/mol

mass(O2)= 45.0 g

similar as ammonia

n (O2)=(45.0 g)/(32 g/mol)

= 1.406 mol

Balanced chemical equation is:

4 NH3 + 5 O2 ---> 4 NO + 6 H2O

1.83456 mol of O2 is required for 1.46765 mol of NH3

by the calculation we have only 1.40625 mol of O2

Thus, the limiting agent will be - O2

now the Molar mass of NO,

= 1*14.01 + 1*16.0

= 30.01 g/mol (similar formula used for NH3)

Balanced equation :

mol of NO formed = (4/5)* moles of O2

= (4/5)×1.40625 (from above calculation)

= 1.125 mol

mass of NO = number of moles × molar mass

= 1.125*30.01

= 33.8 g

Thus, the correct answer would be : 33.8 g

5 0

2 years ago

In a container containing co, h2, and o2, what is the mole fraction of co if the h2 mole fraction is 0.22 and the o2 mole fracti

almond37 [142]

Thank you for posting your question here at brainly. The mole fraction of co if the h2 mole fraction is 0.22 and the o2 mole fraction is 0.58 is 0.20, below is the solution:

mole fraction CO + mole fraction H2 + mole fraction O2 = 1

mole fraction CO = 1 - ( 0.22 + 0.58)=0.20

6 0

2 years ago

Consider a saturated solution formed when 17.5 g of a solute dissolve in 28.3 g of a solvent, giving a total solution volume of

STALIN [3.7K]

Answer:

a) 38.2 % mass

b) 61.8 g solute/100 g solvent

c) 1.65 g/mL

Explanation:

Given the data:

mass of solute = 17.5 g

mass of solvent= 28.3 g

total solution volume= 27.8 mL

a)- mass percent= mass of solute/mass of solution x 100

mass of solution = mass solute + mass solvent = 17.5 g + 28.3 g = 45.8 g

mass % = 17.5 g/45.8 g x 100 = 38.2 % mass

b)- solubility = grams of solute/ 100 g solvent

= 17.5 g x (100 g /28.3 g solvent) = 61.8 g solute/100 g solvent

c)- density = massof solution/total volumesolution = 45.8 g/27.8 mL = 1.65 g/mL

7 0

2 years ago