In an average mass, each entry has equal weight. In a weighted average, we multiply each entry by a number representing its relative importance.
Assume that your class consists of 15 girls and 5 boys. Each girl has a mass of 54 kg, and each boy has a mass of 62 kg.
<em>Average mass</em> = (girl + boy)/2 = (54 kg + 62 kg)/2 = <em>58 kg</em>
<em>Weighted average (Method 1)
</em>
Use the <em>numbers of each</em> gender (15 girls + 5 boys)
,
Weighted average = (15×54 kg + 5×62 kg)/20 = (810 kg + 310 kg)/20
= 1120 kg/20 = <em>56 kg</em>.
If you put all the students on one giant balance, their total mass would be
1120 kg and the average mass of a student would be <em>56 kg.
</em>
<em>Weighted average (Method 2)
</em>
Use the <em>relative percentages</em> of each gender (75 % girls and 25 % boys).
Weighted average = 0.75×54 kg + 0.25×62 kg = 40.5 kg + 15.5 kg = <em>56 kg</em>
Each girl contributes 40.5 kg and each boy contributes 15.5 kg to the <em>weighted average</em> mass of a student.
When sodium hydroxide (NaOH) is added to benzoic acid (C
), sodium benzoate and water (
) are formed because benzoic acid is weak acid and NaOH is strong base. The reaction is shown in diagram 1. To the tube of sodium benzoate, if 6 m HCl is added, sodium benzoate salt will react with HCl and produce benzoic acid and sodium chloride, NaCl. The reaction is shown in diagram 2.
<span>When electrons are excited they get more energy and jump to higher orbitals. As they loose that energy that had excited them in the beginning, they tend to return to their original orbitals and the color that is given off is when this is occurring. </span>
Answer:
34.23 g.
Explanation:
<em>Molarity is defined as the no. of moles of a solute per 1.0 L of the solution.</em>
M = (no. of moles of solute)/(V of the solution (L)).
∴ M = (mass/molar mass)of C₁₂H₂₂O₁₁/(V of the solution (L)).
<em>∴ mass of C₁₂H₂₂O₁₁ = (M)(molar mass)(V of the solution (L)</em> = (1.0 M)((342.3 g/mol)/(0.10 L) = <em>34.23 g.</em>
