CHEMISTRY Questions & Answer

CHEMISTRY
MIDDLE SCHOOL
*PLEASE HELP* ​1) Na2S (aq) + Cd(NO3)2(aq)→CdS (s) + 2NaNO3(aq)  ​ is which type of reaction?

2) Which phrase is the best description of a redox reaction?

A) a reaction in which the exchange of electrons (or oxygen) occurs

B) a reaction in which a precipitate forms as a product

C) a reaction in which two new products are created

D) a reaction that results in the release of heat or light

3) Why does the reaction H2O + Ag→no reaction not proceed to a product?

A) Silver has a lower activity than hydrogen and cannot replace it.

B) Silver has a higher activity than hydrogen and cannot replace it.

C) The reaction proceeds too slowly to create products.

D) The reaction cannot occur because water is a reactant.

4) What is the balanced form of the equation C2H6 + O2→CO2+H2O ?

A) C2H6 + 3O2→2CO2+2H2O

B) C2H6 + 3O2→2CO2+3H2O

C) 2C2H6 + 7O2→4CO2+6H2O 

D) C2H6 + 5O2→3CO2+5H2O

5) The equation 2NaNO3 + CaCl2→2NaCl+Ca(NO3)2 is balanced.

How many atoms of sodium (Na) are there on either side of the equation?

two

four

one

six

6) AgNO3(aq)+Cu(s)→Ag(s)+Cu(NO3)2(aq) is an example of which type of reaction?

A) double-displacement

B) decomposition

C) redox

D) combustion

7)Which example best describes a double displacement reaction?

A)Two compounds combine to form one new compound.

B) The ions of two ionic compounds switch places and a gas is formed.

C) One compound breaks down into two different compounds.

D) A compound reacts with oxygen to release a lot of heat.