No one is 100% sure when particles of matter originated however scientist believe it had to be some time before the Big Bang
Answer: 72.41% and 26.90% respectively.
Explanation:
At 60°C, you can dissolve 46.4g of acetanilide in 100mL of ethanol. If you lower the temperature, at 0°C, you can dissolve just 12.8g, which means (46.4g-12.8g)=33.6g of acetanilide must have precipitated from the solution.
We can calculate recovery as:

So the answer to the first question is 72.41%.
For the second part just use the same formula, the mass of the precipitate is the final mass minus the initial mass, (171mg-125mg)=46mg.

So the answer to the second question is 26.90%.
Answer:
There are 4 tryptophans in the protein.
Explanation:
According to question, protein contains one tyrosine residue and say x number of tryptophans.
Concentration of protein solution = 1.0 micromolar = 
Molar absorptivity of a protein solution : 


Length of the cuvette = l = 1.0 cm
Absorbance of protein solution at 280 nm = A = 0.024
( Beer-Lambert's law)

Solving for x :
x = 4
There are 4 tryptophans in the protein.
near what like open flames? if so false unless it clarifies the solution requires alcohol then its a no go
Answer:
5.158 mol/L
Explanation:
To find the molarity, you need to use the formula:
Molarity (M) = moles / volume (L)
You have been grams sodium carbonate. You need to (1) convert grams Na₂CO₃ to moles (via molar mass), then (2) convert moles Na₂CO₃ to moles HCl (via mole-to-mole ratio from equation), then (3) convert mL to L (by dividing by 1,000), and then (4) use the molarity equation.
<u>Steps 1 - 2:</u>
2 HCl + 1 Na₂CO₃ ----> 2 NaCl + H₂O + CO₂
6.5287 g Na₂CO₃ 1 mole 2 moles HCl
-------------------------- x ------------- x ------------------------- = 0.12318 mole HCl
106 g 1 mole Na₂CO₃
<u>Step 3:</u>
23.88 mL / 1,000 = 0.02388 L
<u>Step 4:</u>
Molarity = moles / volume
Molarity = 0.12318 mole / 0.02388 L
Molarity = 5.158 mole/L
**mole/L is equal to M**