Practice Synthesis Reaction in Chemistry

Use these practice problems to test your method after reviewing the concept explanation and worked examples.

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Quick Recap

A chemical reaction in which two or more simpler substances (elements or compounds) combine to form a single, more complex product.

Building something bigger from smaller parts — like assembling LEGO bricks into a structure.

Showing a random 20 of 50 problems.

Example 1

hard
Identify the reaction type and balance: P4+Cl2→PCl3\text{P}_4 + \text{Cl}_2 \rightarrow \text{PCl}_3.

Example 2

hard
Predict the formula of the product when lithium reacts with oxygen, then write the balanced synthesis equation.

Example 3

hard
N2+3H2→2NH3\text{N}_2 + 3\text{H}_2 \rightarrow 2\text{NH}_3. With 2 mol N2N_2 and 3 mol H2H_2, find the limiting reactant and the moles of NH3\text{NH}_3 formed.

Example 4

challenge
Metal X forms oxide X2O5X_2O_5. If 0.20 mol X reacts fully, how many mol O2O_2 are consumed?

Example 5

medium
Is CO2+C→2COCO_2 + C \rightarrow 2CO a synthesis reaction? Explain via product count.

Example 6

challenge
A 0.48 g sample of Mg burns in oxygen forming MgO. Mass of MgO formed? (Mg=24, O=16)

Example 7

hard
How many grams of Al2O3\text{Al}_2\text{O}_3 (M=102M=102) form when 5.4 g of Al (M=27M=27) reacts with excess O2\text{O}_2?

Example 8

easy
Is N2+3H2→2NH3N_2 + 3H_2 \rightarrow 2NH_3 a synthesis reaction?

Example 9

easy
Write the balanced equation for the synthesis of magnesium oxide from magnesium and oxygen.

Example 10

easy
Identify this reaction type: N2+3H2→2NH3\text{N}_2 + 3\text{H}_2 \rightarrow 2\text{NH}_3.

Example 11

medium
Predict the product and balance: Mg+N2→Mg + N_2 \rightarrow ? (Mg is +2, N is -3)

Example 12

easy
Two elements combine to form one compound. Name the reaction type.

Example 13

easy
Is C+O2→CO2\text{C} + \text{O}_2 \rightarrow \text{CO}_2 a synthesis reaction?

Example 14

medium
Which is the synthesis reaction? (a) CaCO3→CaO+CO2\text{CaCO}_3 \rightarrow \text{CaO} + \text{CO}_2 (b) CaO+CO2→CaCO3\text{CaO} + \text{CO}_2 \rightarrow \text{CaCO}_3

Example 15

easy
Classify: 2Mg+O2→2MgO2Mg + O_2 \rightarrow 2MgO. What reaction type is this?

Example 16

medium
Predict the product and write the balanced equation for the synthesis reaction between sodium and chlorine gas.

Example 17

challenge
When P4\text{P}_4 (M=124M=124) reacts with excess O2\text{O}_2 to form P4O10\text{P}_4\text{O}_{10} (M=284M=284), what mass of product forms from 6.20 g of P4\text{P}_4?

Example 18

medium
Write the balanced synthesis of ZnS\text{ZnS} from its elements.

Example 19

easy
Write the balanced synthesis of calcium chloride from its elements.

Example 20

challenge
A 5.85 g sample of Na (M=23M=23) reacts with Cl2\text{Cl}_2 (M=71M=71) to form NaCl. If 11.7 g of NaCl (M=58.5M=58.5) is collected, find the percent yield.
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