2.94
×
10
24
⋅
molecules
6.022
×
10
23
⋅
molecules
⋅
mol
−
1
×
142.3
⋅
g
⋅
mol
−
1
≅
700
⋅
g
The periods inside the Periodic Table is B. a horizontal row, and is numbered 1 through 7
hope this helps
Answer:
Explanation:
Hello,
In this case, we use the Avogadro's number to compute the molecules of C2F4 whose molar mass is 100 g/mol contained in a 485-kg sample as shown below:
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Answer:
0.0400 g for the example given below.
Explanation:
pH value is not provided, so we'll solve this problem in a general case and then we will use an example to justify it.
- By definition, .
- NaOH is a strong base, as it's a hydroxide formed with a group 1A metal, so it dissociates fully in water by the equation: .
- From the equation above, using stoichiometry we can tell that the molarity of hydroxide is equal to the molarity of NaOH: .
- Concentration of hydroxide is then equal to the ratio of moles of NaOH and the volume of the given solution. Moles themselves are equal to mass over molar mass, so we obtain: .
- We also know that . Take the antilog of both sides: .
- Solve for the mass of NaOH: .
Now, let's say that pH is given as 12.00 and we use a 100-ml volumetric flask. Then we would obtain:
Ozone is mainly found in two regions of the Earth's atmosphere. Most ozone (about 90%) resides in a layer that begins between 6 and 10 miles (10 and 17 kilometers) above the Earth's surface and extends up to about 30 miles (50 kilometers). This region of the atmosphere is called thestratosphere.