Worksheets8th Science 8.5DE
Total questions: 16
Worksheet time: 15mins
In which of these compounds are there twice as many oxygen atoms as hydrogen atoms?
H3PO4
H2SO4
HCIO3
H2O
How many atoms of oxygen are in a molecule of glucose (C6H12O6)?
4
6
12
24
How many atoms in all are found in the compound above?
3
4
5
6
How many elements are in C6H12O6?
1
2
3
4
Sodium sulfate is used in laundry detergent. It is a compound that contains 2 atoms of sodium, 1 atom of sulfur, and 4 atoms of oxygen. What is the correct chemical formula for sodium sulfate?
NA2SO4
Na2S2O4
Na2SO4
Na2SO8
What is a chemical reaction?
A chemical reaction is a process that leads to the transformation of one set of chemical substances to another.
A chemical reaction is a process that leads to the destruction of chemical substances.
A chemical reaction is a process that leads to the separation of chemical substances.
A chemical reaction is a process that leads to the formation of new elements.
How do you balance a chemical equation?
By adjusting the coefficients in front of the chemical formulas.
By changing the subscripts in the chemical formulas.
By adding or removing elements from the equation.
By changing the order of the chemical formulas.
What is the coefficient in a chemical equation?
The coefficient in a chemical equation is the number that appears after a chemical formula.
The coefficient in a chemical equation is the sum of the reactants and products.
The coefficient in a chemical equation is the number of atoms in a molecule.
The coefficient in a chemical equation is the number that appears in front of a chemical formula.
What is the purpose of counting atoms in a chemical equation?
To determine the stoichiometry of the reaction.
To determine the temperature of the reaction.
To calculate the molar mass of the compound.
To balance the equation.
What is the law of conservation of mass?
Mass can change form in a chemical reaction.
Mass can be destroyed in a chemical reaction.
Mass can be created in a chemical reaction.
Mass cannot be created or destroyed in a chemical reaction.
Sodium sulfate is used in laundry detergent. It is a compound that contains 2 atoms of sodium, 1 atom of sulfur, and 4 atoms of oxygen. What is the correct chemical formula for sodium sulfate?
NA2SO4
Na2S2O4
Na2SO4
Na2SO8
During an experiment, a student combines a solid, metallic substance with a clear liquid in a beaker. The mixtures turns hot, produces bubbles, and sparks. Based on the observations, the student can conclude that –
A. a phase change has occurred.
B. atoms have been rearranged to form a new substance.
C. the products are likely harmful to human skin.
D. the metal substance is a poor conductor of heat.
A model of one molecule of a chemical compound is shown. What is the correct way to write the formula for three molecules of this compound?
A. 2H2O
B 3(2H2O)
C. H2O2
D. 3H2O2
A chemical formula is shown below. The subscripts in a chemical formula represent the-
NaNO2
A. number of atoms of the element in front of the subscript.
B. atomic mass of the heaviest element in the compound.
C. atomic number of the element that follows the subscript.
D. column on the Periodic Table of the element next to it.
A chemical formula is provided below. How many atoms are contained in the substance?
H2SO4
3
6
7
10
When vinegar and baking soda are combined, bubbles begin to form. Bubbles are evidence of a chemical reaction because they -
A. are less dense than air.
B. form at a fast rate.
C. released a gas
D. have no mass.
