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2 years ago

Brainliest for best answer

Chemistry

2 answers:

Margaret [11]2 years ago

4 0

b is answer

Explanation:

please follow me

aleksandrvk [35]2 years ago

4 0

Answer:

B is the answer

Explanation:

A is incorrect as there is 2 O2 on the RHS while there is only 1 O2 on one side

B is correct as it is going through a process called combustion and I don't feel like explaining it is too long T^T

C is incorrect as the 3 results in multiply N (3 Nitrogen) while there is only one N2

D is definitely incorrect -.-

Hope this helps

(P.S. I lost a lot of my brain cells x-x)

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Fe(NO3)2 not sure how to get the oxidation numbers of all elements

Shtirlitz [24]

You must remember that oxidation number of hydrogen in acids is always +1, oxidation number of oxygen in oxides & acids is always -2... metals has always oxidation number on plus!

group NO3 comes from HNO3...and oxidation number of whole acid group is always on minus and equal to the amount of hydrogen atoms in this acid... so oxidation number of NO3 = -1

we have 2 NO3 groups so 2*(-1) = -2 and that is the reason why oxidation number of Fe in this formula must be +2... because sum of all elements always gives 0!

Now we could count of oxidation number for nitrogen... we write HNO3 and start counting from right to left:
3*(-2) from oxygens + 1 from hydrogen = -5
so nitrogen must have +5 oxidation number... because sum all in formula must be 0.

4 0

3 years ago

in 1912, chemist fritz haber developed a process that combined nitrogen from the air with hydrogen at high temperatures and pres

Virty [35]

Explain whether this is a chemical or physical change, and why. does it involve elements, compounds, mixtures, or pure substances?

If the process involves a chemical reaction then surely it is a chemical change where new bonds are being formed from the collision of the reactants.

Describe how many atoms are involved before and after. what do you notice about the number of atoms?

From the balanced chemical reaction, we see that we need 1 mol of N2 gas and 3 mol of H2 in order to form 2 mol of NH3.

3 0

3 years ago

What is the kinetic energy of a 10 kg object that has a velocity of 1.5 m/s

katen-ka-za [31]

Answer: 11.25 J

Explanation: Kinetic energy is expressed as the product of mass and the squared of velocity divided by 2.

3 0

4 years ago

Read 2 more answers

A gas mixture at 535.0°C and 109 kPa absolute enters a heat exchanger at a rate of 67.0 m3/hr. The gas leaves the heat exchanger

SVEN [57.7K]

Answer:

the heat rate required to cool down the gas from 535°C until 215°C is -2.5 kW.

Explanation:

assuming ideal gas behaviour:

PV=nRT

therefore

P= 109 Kpa= 1.07575 atm

V= 67 m3/hr = 18.6111 L/s

T= 215 °C = 488 K

R = 0.082 atm L /mol K

n = PV/RT = 109 Kpa = 1.07575 atm * 18.611 L/s /(0.082 atm L/mol K * 488 K)

n= 0.5 mol/s

since the changes in kinetic and potencial energy are negligible, the heat required is equal to the enthalpy change of the gas:

Q= n* Δh = 0.5 mol/s * (- 5 kJ/mol) =2.5 kW

7 0

3 years ago

Why do you require an acid catalyst to make an ester? Why not just mix acid and alcohol? Describe an alternate method of making

djverab [1.8K]

Answer:Acid catalyst is needed to increase the electrophilicity of Carbonyl group of Carboxylic acid as alcohol is a weak nucleophile.

Alternatively esters can be synthesised by converting carboxylic acid into acyl chloride using thionyl chloride(SOCl_{2} and then further treating acyl chloride with alcohol.

Carboxylic acid and esters can be easily distinguished on the basis of IR as carboxylic acid would contain a broad intense peak in 2500-3200cm_{-1} corresponding to OH stretching frequency whereas esters would not contain any such broad intense peak.

Alcohol and esters can also be distinguished using IR as alcohols would contain a broad intense peak at around 3200-3600cm_{-1}

Explanation: For the synthesis of esters using alcohol and carboxylic acid we need to add a little amount of acid in the reaction . The acid used here increases the electrophilicity of carbonyl carbon and hence makes it easier for a weaker nucleophile like alcohol to attack the carbonyl carbon of acid.

The oxygen of the carbonyl group is protonated using the acidic proton which leads to the generation of positive charge on the oxygen. The positive charge generated is delocalised over the whole acid molecule and hence the electrophilicity of carbonyl group is increased. Kindly refer attachment for the structures.

If we simply mix the acid and alcohol then no appreciable reaction would take place between them and ester formation would not take place because the carboxylic acid in that case is not a good electrophile whereas alcohol is also not a very strong nucleophile which can attack the carbonyl group.

Alternatively we can use thionyl chloride or any other reagent which can convert the carboxylic acid into acyl chloride. Acyl chloride is very elctrophilic and alcohol can very easily attack the acyl chloride and esters could be synthesized.

The carboxylic acid and ester can very easily be distinguished on the basis of broad intense OH stretching frequency peak at around 2500-3200cm_{-1} . The broad intense OH stretching frequency peak is present in carboxylic acids as they contain OH groups and absent in case of esters .

Likewise esters and alcohols can also be distinguished on the basis IR spectra as alcohols will have broad intense spectra at around 3200-3600cm_{-1}corresponding to OH stretching frequency whereas esters will not have any such peak. Rather esters would be having a Carbonyl stretching frequency at around 1720-1760

4 0

3 years ago