Use the periodic table to answer the question.
An illustration shows the periodic table.
Which element has the same number of valence electrons as bromine (Cl)?
Selenium (Se)
potassium (K)
krypton (Kr)
Fluorine (F)
Fluorine (F)
Why are Chorine (Cl) and Fluorine (F) in the same group on the periodic table?
They have similar atomic weights.
They are both colorless.
They have similar reactivity.
They are both metals
They have similar reactivity.
How do you know if a chemical change has taken place? (1 point)
Responses
A loud noise can be heard.
A loud noise can be heard.
The substance has changed from one phase to another (such as solid to liquid).
The substance has changed from one phase to another (such as solid to liquid).
Chemical changes involve breaking something into smaller peices that have the same properties as the origanal substance.
Chemical changes involve breaking something into smaller peices that have the same properties as the origanal substance.
New substances are formed.
New substances are formed.
Why do we balance chemical equations and how does this relate to the Law conservation of matter? (1 point)
Responses
it shows that all compounds remain bonded after the reaction
it shows that all compounds remain bonded after the reaction
it shows that no atoms have been gained or lost during the reaction
it shows that no atoms have been gained or lost during the reaction
it shows that the properties of the elements stay the same after the reaction
it shows that the properties of the elements stay the same after the reaction
it shows that only physical changes follow the Law of Conservation of Mass
it shows that no atoms have been gained or lost during the reaction
Sodium reacts with chlorine to form the compound sodium chloride, or salt. The chemical formula below shows how the two elements combine into a compound.
2Na + Cl2 → 2NaCl
If the total mass of the reactants is 58.44 amu, what will be the total mass of the products?
(1 point)
Responses
58.44 amu
58.44 amu
29.22 amu
29.22 amu
60 amu
60 amu
116.88 amu
116.88 amu
The total mass of the products would be 58.44 amu.
Which procedure could be used to demonstrate that matter is conserved during a physical change?(1 point)
Responses
Find the mass of a raw egg. Cook the egg. Find the mass of the cooked egg.
Find the mass of a raw egg. Cook the egg. Find the mass of the cooked egg.
Find the mass of a piece of paper. Tear the paper into a bunch of peices and find the overall mass of all the pieces.
Find the mass of a piece of paper. Tear the paper into a bunch of peices and find the overall mass of all the pieces.
Use a thermometer to determine if heat is released when vinegar and baking soda are mixed.
Use a thermometer to determine if heat is released when vinegar and baking soda are mixed.
Burn wook in you woodstove and measure the heat that is released.