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miv72 [106K]
3 years ago
12

When do we observe more than one broad band in the fluorescence spectrum?

Chemistry
1 answer:
GalinKa [24]3 years ago
8 0
Everydayyyyyyyyyyyyyyy
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A 52.0-mL volume of 0.35 M CH3COOH (Ka=1.8×10−5) is titrated with 0.40 M NaOH. Calculate the pH after the addition of 23.0 mL of
Georgia [21]

NaOH reacts with CH3COOH in 1:1 molar ratio to produce CH3COONa 

NaOH + CH3COOH → CH3COONa + H2O 

Mol CH3COOH in 52.0mL of 0.35M solution = 52.0/1000*0.35 = 0.0182 mol CH3COOH 

Mol NaOH in 19.0mL of 0.40M solution = 19.0/1000*0.40 = 0.0076 mol NaOH 

These will react to produce 0.0076 mol CH3COONa and there will be 0.0182 - 0.0076 = 0.0106 mol CH3COOH remaining in solution unreacted . Total volume of solution = 52.0+19.0 = 71mL or 0.071L 

Molarity of CH3COOH = 0.0106/0.071 = 0.1493M 

CH3COONa = 0.0076 / 0.071 = 0.1070M 

pKa acetic acid = - log Ka = -log 1.8*10^-5 = 4.74. 

pH using Henderson - Hasselbalch equation: 

pH = pKa + log ([salt]/[acid]) 

pH = 4.74 + log ( 0.1070/0.1493) 

pH = 4.74 + log 0.717 

pH = 4.74 + (-0.14) 

pH = 4.60.

7 0
3 years ago
PLEASE HELP <3
frutty [35]
In order for carbon to be stable and have 8 electrons, it must make 4 total covalent bonds.

In prefer for oxygen to be stable and have 8 electrons, it must make 2 covalent bonds.

So, we can deduce that CO2 looks like this:

O=C=O

This molecule has two double bonds.

Pssst...Can I get a brainliest?
8 0
3 years ago
The stronger the intermolecular forces, the _______the energy needed to separate the molecules, the ____________the boiling poin
slamgirl [31]

Answer:

higher, higher

Explanation:

It takes more energy to rip apart stronger bonds (that's mostly just common sense there). The boiling point increases because it would take more energy to get the molecules to go from a stuck together liquid, to separating in a gaseous form.

7 0
3 years ago
A mixture was found to contain 1.05 g if silicone dioxide, 0.69 g cellulose, 1.82 g of calium carbonate. what percent of calcium
djverab [1.8K]
1,05+ 0,69 + 1,82 = 3,56g of mixture

%CaCO₃: 1,82/3,56×100% = 0,5112×100% = 51,12%
5 0
3 years ago
During a reaction 24 cubic cm of carbon dioxide was given off. After 8 minutes no more gas was produced and the reaction was com
yuradex [85]

Answer:

Explanation:

Given parameters:

Volume of CO₂ = 24cm³

time taken for the reaction to complete = 8minutes.

Unknown:

rate of reaction

Soution

The reaction rate is a measure of speed of a chemical reaction. It is often calculated using the expression below:

    Reaction rate = \frac{change in concentration of reactant/product}{time taken}

   Reaction rate = \frac{24}{8} = 3cm³/min

In this reaction, 3cm³ of carbon dioxide were produced per minute

7 0
3 years ago
Read 2 more answers
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