<span>A chemist adds 155.0ml of a 4.10 X 10^-5 mmol/L of a zinc oxalate (ZnC2O4)solution to a reaction flask. Calculate the mass in micrograms of zinc oxalate the chemist has added to the flask.
1mmol = 10^-3 mol
Therefore 4.10*10^-5mmol = 4.10*10^-8mol
molar mass ZnC2O4 = 65.39+(2*12.011)+(4*15.99) = 153.372g/mol
You have 4.10*10^-8 mol/litre =153.372 * 4.10*10^-8 = 6.29*10^-6 grams / litre (* see below)
But you have 155ml. Mass of ZnC2O4 = 155/1000*6.29*10^-6 g
Mass is = 9.75*10^-7 grams
1µg = 10^-6 g
You then have 9.75*10^-7/10^-6 = 0.975µg ZnC2O4
(*see below) at this point you could have said:
1µg = 10^-6 g therefore you have a solution of 6.29µg per litre,
155ml = 6.29*155/1000 = 0.975µg ZnC2O4</span>
A;4, b;6, c;7, d;5, e;8, f;3
According to Newton's first law of motion, it takes an unbalanced force to move an object at rest.
I hope this helps :)
Answer:
5010J
Explanation:
The following data were obtained from the question:
Mass (m) = 15g
Heat of fusion (ΔHf) = 334J/g
Heat required (Q) =..?
The heat energy required to melt the ice can be obtained as follow:
Q = m·ΔHf
Q = 15 x 334
Q = 5010J
Therefore, the heat energy required to melt the ice is 5010J.
