Concord High School Chemistry

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Practice Problems Here:

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Practice Problem #2:

Rb₃AsO₄ + BaCr₂O₇ -->

Answer to Practice Problem #2:

1. Identify the type of reaction.

Double-replacement reaction.

Rb⁺ is a cation, so it will switch with Ba²⁺ (also a cation).

Rb₃AsO₄ + BaCr₂O₇ -->

2. Write out the products of the chemical reaction.

Switch the cations, since this is single-replacement:

Rb₃AsO₄ + BaCr₂O₇ --> Rb Cr₂O₇ + Ba AsO₄

Then write the formulas of the products based on their charges.

Rb = +1, Cr₂O₇ = -2, so the formula is Rb₂Cr₂O₇.

Ba = +2, AsO₄= -3, so the formula is Ba₃(AsO₄)₂.

Rb₃AsO₄ + BaCr₂O₇ --> Rb₂Cr₂O₇ + Ba₃(AsO₄)₂

3. Balance the equation.

Rb₃AsO₄ + BaCr₂O₇ --> Rb₂Cr₂O₇ + Ba₃(AsO₄)₂

Balance this equation by putting the coefficients in front of the compounds.

Last, double check that all numbers of atoms of each element is equal.

Answer to Problem: 2Rb₃AsO₄ + 3BaCr₂O₇ --> 3Rb₂Cr₂O₇ + Ba₃(AsO₄)₂