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Makovka662 [10]
3 years ago
6

What are observations that indicate a chemical change has occurred ?

Chemistry
1 answer:
sukhopar [10]3 years ago
4 0

Answer:

Change of odor

Change of color

Change in temperature

Change in energy

Change of composition

Formation of gases

The decomposition of organic matter

The Change is irreversible

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An amide may be produced by reacting an acid chloride with
Elanso [62]

Answer:

An amide may be produced by reacting an acid chloride with ammonia.

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3 years ago
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Is it possible for the equivalence point of a titration to not be at pH 7? Explain your answer.
lara31 [8.8K]
<span>The reason it will be 7 for some titrations is that when you  titrates a strong acid with a strong base for example  HCl and NaOH the salt formed is conjugate base of strong acid and will be a very weak base
 That means that it cannot produce any OH^-1 and all the H+ has been converted to water.The only source of H+ or OH is water with a Ka of 10^-14 so the pH = -log [H+]=-log 10^-7 = 7 
second reason is 
When you titrates a weak acid with strong base at equivalence point 
only a water solution of the conjugate base exists 

CH3COOH + NaOH ----- Na+ CH3COO^-1 + H2O 
Since the conjugate base is the conjugate base of a weak acid it will hydrolyze in water like so 
for instance Na+ CH3COO^-1 + HCl---- CH3COOH + NaCl the equivalence point will be way BELOW 7 and in the case of above will be less than 5. So pH of 7 at equivalence point is only reached in strong acid strong base titrations.
hope this helps</span>
5 0
3 years ago
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A solution that is 0.20 m in hcho2 and 0.15 m in nacho2 find ph
Mashutka [201]
We are given
0.2 M HCHO2 which is formic acid, a weak acid
and
0.15 M NaCHO2 which is a salt which can be formed by reacting HCHO2 and NaOH

The mixture of the two results to a basic buffer solution
To get the pH of a base buffer, we use the formula
pH = 14 - pOH = 14 - (pKa - log [salt]/[base])

We need the pKa of HCO2
From, literature, pKa = 1.77 x 10^-4
Substituting into the equation
pH = 14 - (1.77 x 10^-4 - log 0.15/0.2)
pH = 13.87

So, the pH of the buffer solution is 13.87
A pH of greater than 7 indicates that the solution is basic and a pH close to 14 indicates high alkalinity. This is due to the buffering effect of the salt on the base.
5 0
3 years ago
Which is the noble gas notation for chlorine?
Nikitich [7]
The answer is [Ne] 3s^2 3p^5 because chlorine is the fifth element in the 3rd row of elements in in p orbital
3 0
4 years ago
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Calculate the percentage by mass of oxygen in trioxonitrate (v) acid, (HNO3). [ H=1, N=14, O=16]​
Vadim26 [7]

Answer:

Percentage by mass of oxygen = 76.20% (Approx)

Explanation:

Given:

HNO3

H=1, N=14, O=16]

Find:

Percentage by mass of oxygen

Computation:

HNO3

Total mass = 1 + 14 + 3(16)

Total mass = 63

Mass of oxygen = (3)(16) = 48

Percentage by mass of oxygen = [48/63]100

Percentage by mass of oxygen = 76.20% (Approx)

4 0
3 years ago
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