Answer:
In my opinion, water is a compound.
Explanation:
Water is mixed from Oxygen(O) and Hydrogen(H) and they cannot be splitted.
Sorry if there any mistakes
The molarity of the stock solution of luminol is 1.2 M
<u><em>calculation</em></u>
step 1: find the moles of luminol using (moles= mass/molar mass) formula
molar mass of Luminol= 177 g/mol
moles is therefore= 16.0 g/ 177 g/mol=0.0904 moles
Step 2: find the molarity using (molarity= moles/volume in liters) formula
convert Ml into liters = 75.0/1000= 0.075 L
molarity is therefore= 0.0904 moles/ 0.075 L= 1.2M
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.
