Answer: A. Perform a gravity filtration with a stemless funnel.
Explanation: Gravity filtration with a stemless funnel prevent blocking up the funnel. Undissolved sample may come out in the stem when the solution cools down thus will be blocking the funnel. Using stemless funnel prevent this problem.
Answer:
Pyrophoricity is a property of metals and oxides of lower oxidation states, including radioactive ones, in which they spontaneously ignite during or after stabilization.
Answer:
Starting from your own home is the best way to reduce plastic pollution. You can reduce it by stop using plastic bags, water bottles, anything that is plastic. You can reuse things instead. Use less energy. Turn off the lights whenever you leave the house or if you aren't using it. Lastly, conserve water. Don't let the water running if you aren't using it.
Hope this helps! :)
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.
Answer:
126.18 hr
Explanation:
Data given:
1 mL of water = 20 drops
count rate = 10 drops/s
time in hours for one gallon = ?
Solution:
First we calculate number of mL (milliliter) of water in gallon
As we know
1 gallon = 3785.4 mL
As,
1 galon consist of 3785.4 mL of water, so now we count number of drops that contain 3785.4 mL of water
As we Know 1 mL water contain 20 drops then 3785.4 mL of water contain how many drops:
Apply unity formula
1 mL water ≅ 20 drops
3785.4 mL water ≅ X drops
Do cross multiplication
X drops of water = 20 drops x 3785.4 mL / 1 mL
X drops of water = 75708 drops
So, we come to know that one gallon contain 75708 drops of water and we have to calculate the time in hour to count these drops
First we calculate time in seconds
As we Know 10 drops water count in one second then how many seconds it will take to count 75708 drops
Apply unity formula
1 second ≅ 10 drops
X second ≅ 75708 drops
Do cross multiplication
X second = 1 second x 75708 drops / 10 drops
X second = 7570.8 second
So it take 7570.8 second to count 1 gallon water drops
Now convert seconds to hours
As,
60 seconds = 1 hr
7570.8 second = 7570.8 / 60 = 126.18 hr
So it take 126.18 hr to count 1 gallon water drops.
