Answer:
The concentration the student should write down in her lab is 2.2 mol/L
Explanation:
Atomic mass of the elements are:
Na: 22.989 u
S: 32.065 u
O: 15.999 u
Molar mass of sodium thiosulfate, Na2S2O3 = (2*22.989 + 2*32.065 + 3*15.999) g/mol = 158.105 g/mol.
Mass of Na2S2O3 taken = (19.440 - 2.2) g = 17.240 g.
For mole(s) of Na2S2O3 = (mass taken)/(molar mass)
= (17.240 g)/(158.105 g/mol) = 0.1090 mole.
Volume of the solution = 50.29 mL = (50.29 mL)*(1 L)/(1000 mL)
= 0.05029 L.
To find the molar concentration of the sodium thiosulfate solution prepared we use the formula:
= (moles of sodium thiosulfate)/(volume of solution in L)
= (0.1090 mole)/(0.05029 L)
= 2.1674 mol/L
Answer:
25% gold.
Explanation:
6 is 25 percent of 24, so 6 karat gold would be 25% gold.
Answer:
The advantages described below
Explanation:
Advantages of a balanced chemical equation versus word equation:
- easier to read: chemical equations typically only take one line and they include all the relevant information needed. They are short-hand notations for what we describe in words.
- balanced chemical equations show molar ratio in which reactants react and the molar ratio of the products. Those are coefficients in front of the species. This is typically not included in a word equation, for example, hydrochloric acid reacts with potassium hydroxide. The latter statement doesn't describe the molar ratio and stoichiometry.
- includes relevant information, such as catalysts, temperature and pressure above the arrow in the equation. We wouldn't have this in a word equation most of the time.
- shows the stoichiometry of each compound itself, e. g. if we state 'ammonia', we don't know what atoms it consists of as opposed to .
- includes states of matter: aqueous, liquid, gas, solid. This would often be included in a word equation, however.
Answer : The concentration of and at equilibrium is, 0.0158 M and 0.00302 M respectively.
Explanation :
First we have to calculate the concentration of
Now we have to calculate the value of equilibrium constant (K).
The given chemical reaction is:
Initial conc. 0.0163 0.00415 0.00276
At eqm. (0.0163-2x) (0.00415+x) (0.00276+x)
As we are given:
Concentration of at equilibrium = 0.00467 M
That means,
(0.00415+x) = 0.00467
x = 0.00026 M
Concentration of at equilibrium = (0.0163-2x) = (0.0163-2(0.00026)) = 0.0158 M
Concentration of at equilibrium = (0.00276+x) = (0.00276+0.00026) = 0.00302 M