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: it consists of two simple machines: a lever and a wheel and axle. Effort is applied to the lever by picking up the handles of the wheelbarrow.
Explanation:
Answer : The value of rate of reaction is 
Explanation :
Rate law : It is defined as the expression which expresses the rate of the reaction in terms of molar concentration of the reactants with each term raised to the power their stoichiometric coefficient of that reactant in the balanced chemical equation.
The given chemical equation is:

Rate law expression for the reaction is:
![\text{Rate}=k[NO]^a[O_2]^b](https://tex.z-dn.net/?f=%5Ctext%7BRate%7D%3Dk%5BNO%5D%5Ea%5BO_2%5D%5Eb)
As per question,
a = order with respect to
= 2
b = order with respect to
= 1
Thus, the rate law becomes:
![\text{Rate}=k[NO]^2[O_2]^1](https://tex.z-dn.net/?f=%5Ctext%7BRate%7D%3Dk%5BNO%5D%5E2%5BO_2%5D%5E1)
Now, calculating the value of rate of reaction by using the rate law expression.
Given :
k = rate constant = 
[NO] = concentration of NO = 
= concentration of
= 
Now put all the given values in the above expression, we get:


Hence, the value of rate of reaction is 
Thermal (heat) energy is ur answer mate
Hope it helps