<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>
Answer:
option C is correct = 1.14 × 10²² molecules of CO₂
Explanation:
Given data:
Number of moles of CO₂ = 0.0189 mol
Number of molecules = ?
Solution:
The given problem will solve by using Avogadro number.
It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance.
The number 6.022 × 10²³ is called Avogadro number.
For example,
18 g of water = 1 mole = 6.022 × 10²³ molecules of water
For given question:
1 mole of CO₂ = 6.022 × 10²³ molecules of CO₂
0.0189 mol of CO₂ × 6.022 × 10²³ molecules of CO₂ / 1mol
1.14 × 10²² molecules of CO₂
Thus, option C is correct.
Answer:
1 gramo de metano aporta 50.125 kilojoules.
1 gramo de metano aporta 48.246 kilojoules.
Explanation:
La cantidad de energía liberada por la combustión de una unidad de masa del hidrocarburo (), en kilojoules por mol, es igual a la cantidad de energía liberada por mol de compuesto (), en kilojoules por mol, dividido por su masa molar (), en gramos por mol:
(1)
A continuación, analizamos cada caso:
Metano
1 gramo de metano aporta 50.125 kilojoules.
Octano
1 gramo de metano aporta 48.246 kilojoules.
Answer:
A divergent boundary is when the plates move apart from each other. When the plates part, magma from under either plate rises and forms a volcano. A hotspot is the third place a volcano can form. This particular type is the least common.
Explanation:
Excuse me not giving an explanation; I haven't even learned chemistry before. I usually give explanations for math/english.
I think it would be for flourine: 7
aluminum: 8
can't help with the rest...
sorry!