CHEMISTRY MIDDLE SCHOOL

Which of the following is an example of a double replacement reaction? (a)3Fe + 2O2 Fe3O4
(b) BaCl2 + K2CO3 BaCO3 + 2KCl
(c) NiCO3 NiO + CO2
(d) Cl2 + 2NaBr 2NaCl + Br2

Answers

Answer 1
Answer:

Answer: The correct answer is Option b.

Explanation:

Double displacement reactions are defined as the reactions in which exchange of ions takes place.

AB+CD\rightarrow CB+AD

For the given options:

Option a:3Fe+2O_2\rightarrow Fe_3O_4

This is an example of synthesis reaction.

Option b:BaCl_2+K_2CO_3\rightarrow BaCO_3+2KCl

This is an example of double displacement reaction.

Option c:NiCO_3\rightarrow NiO+CO_2

This is an example of decomposition reaction.

Option d:Cl_2+2NaBr\rightarrow 2NaCl+Br_2

This is an example of single displacement reaction.

From the above information, the correct answer is Option b.
Answer 2
Answer: b) is an example of a Double Displacement Reaction:

Ba  Cl2 + K2 CO3  ---> Ba  CO3 + 2K   Cl 
A    B       C   D             A    D           B   C

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Movement of molecules from an area of lower concentration to one of higher concentration with carrier molecules, using energy, is called ______________. A.
osmosis

B.
mitosis

C.
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D.
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Answers

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Complete the following chemical equations BaCl2.2H2O

Answers

Answer:

BaCl_2.2H_2 O > BaCl_2  + 2H_2 O

Explanation:

Balancing is making the number of atoms of each element same on both the sides  (reactant and product side).

To find the number of atoms of each element we multiply coefficient * subscript  

For example 5 Ca_1 Cl_2 contains  

5 × 1 = 5 ,Ca atoms and

5 × 2 = 10, Cl atoms  

If there is a bracket in the chemical formula  

For example 3Ca_3 (P_1 O_4 )_2 we multiply coefficient × subscript × number outside the bracket to find the number of atoms  

(Please note: 3 is the coefficient, and if there is no number given then 1 will be the coefficient )

So

3 × 3 = 9 , Ca atoms  

3 × 1 × 2 = 6, P atoms  

3 × 4 × 2 = 24, O atoms are present.

So

Let us balance the equation given

BaCl_2.2H_2 O > BaCl_2  + 2H_2 O

(balanced  equation)

Reactant side              Elements               Product side

1                                         Ba                                1

2                                         Cl                                 2

4                                          H                                 4

2                                          O                                 2

Balanced!!!

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Answers

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Answers

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Answers

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Answers

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