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WorksheetsHW Stioch General questions
Total questions: 20
Worksheet time: 1hrs 14mins
What is the empirical formula for N2S3?
NS
N3S2
N2S3
N1S1.5
Given the following: 42.07g Na, 18.89g P, and 39.04g O, determine the empirical formula.
NaPO2
Na2PO3
Na3PO4
NaPO4
A compound consists of 72.2% magnesium(Mg) and 27.8% nitrogen(N) by mass. What is the empirical formula?
Mg4N3
MgN2
Mg3N2
MgN
What is the molecular formula if the empirical formula is CH2O and the molecular molar mass is 180.18?
CH2O
C2H4O2
C4H8O4
C6H12O6
Basic aluminium diacetate – Its molecular formula is HOAl(CH3CO2)2 How many total atoms are in this molecule?
4
12
17
20
Determine the amount of moles in CuBr that are in 276.9 g of the compound.
3.2 mol
1.7 mol
2.1 mol
1.9 mol
What is the chemical formula for iron(III) chloride hexahydrate?
FeCl3·6H2O
FeCl3·3H2O
Fe2Cl6·6H2O
Fe3Cl6·H12O3
How are anhydrous compounds different from hydrates?
Anhydrous compounds contain more water molecules than hydrates
Anhydrous compounds and hydrates are the same
Anhydrous compounds do not contain water molecules, unlike hydrates
Anhydrous compounds use Greek letters to indicate the number of water molecules present
MgCl2 --> Mg4+ Cl2
Jim measures 10.5 g of HgO into an open test tube and heats it. The heat causes the HgO to decompose into Hg and O2. After the reaction, Jim finds the mass of the test tube to be 9.7g. Which of the following best explains his observation.
a. the decomposition of HgO does not obey the law of conservation of mass
b. he made errors in measurements
c. 0.8 g of oxygen gas is lost from the tube.
d. Heating destroys some mass.
The formula below represents the chemical reaction between the elements hydrogen and oxygen when the compound water is formed.
2H2 + O2 → 2H2O
This equation supports the law of conservation of mass because
a. the total number of hydrogen and oxygen atoms in the reactants and products is twelve.
b. the mass of hydrogen in the reactants is equal to the mass of the water in the product
c. the same number of atoms of the elements hydrogen and oxygen are in the reactants as are in the products.
d. atoms of the elements hydrogen and oxygen react to form molecules of the compound water.
Which of the following best illustrates the Law of Conservation of Mass?
a. H2SO4 → H2O + SO2
b. H2SO4 → 2H2O2 + SO2
c. 2H2SO4 → 2H2O + SO3
d. H2SO4 → H2O + SO3
2H2 + O2 --> 2H2O
2H2O2 →2 H2O + O2
Example: H2
