Question

question 9 of 29
how many atoms of oxygen? (1.4 points)
extra content
4k₂co₃
a. 6
b. 8
c. 10
d. 12
e. 14

question 10 of 29
how many atoms of oxygen? (1.4 points)
extra content
5ga₂(cr₂o₇)₃
a. 7
b. 21
c. 35
d. 105

Explanation:

Step1: Analyze the formula \(4K_2CO_3\)

In one \(K_2CO_3\) unit, the number of oxygen atoms is \(3\) (from \(CO_3\)).

Step2: Multiply by the coefficient

Since there are \(4\) \(K_2CO_3\) units, the total number of oxygen atoms is \(4\times3 = 12\).

Step3: Analyze the formula \(5Ga_2(Cr_2O_7)_3\)

In one \((Cr_2O_7)\) unit, the number of oxygen atoms is \(7\).

Step4: Consider the sub - coefficient and the overall coefficient

In \(Ga_2(Cr_2O_7)_3\), the number of \((Cr_2O_7)\) units is \(3\). And there are \(5\) \(Ga_2(Cr_2O_7)_3\) units. So the total number of oxygen atoms is \(5\times3\times7=105\).

Answer:

For \(4K_2CO_3\): D. 12
For \(5Ga_2(Cr_2O_7)_3\): D. 105