A coffee shop sells 5 different types of cake and 6 different kind of drinks. Ruby wants to order a cake and a drink. How many d
1 answer:
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Answer: σ: 2.76
Step-by-step explanation:
Count, N: 5
Sum, Σx: 125
Mean, μ: 25
Variance, σ2: 7.6
Steps
look at attached pic for formula
σ^2 =
⇒
⇒ 7.6
σ =
⇒ 2.756809750418
⇒ or 2.76
Answer:
a. 8.75 M NaOH
b. 0.425 M CuCl₂ or 0.43 M CuCl₂
c. 0.067 M CaCO₃ or 0.07 M CaCO₃
Step-by-step explanation:
Molality is computed using the formula:
So first thing you need to do is determine how many moles of solute there are and divide it by the solution in liters.
Converting mass to moles, you need to get the mass of each solute per mole. You can use the periodic table to get the atomic mass (which is the grams per mole of each atom) of each of the elements involved. Then add them up and you will have how many grams per mole of each compound.
1. 35.0g of NaOH in 100ml H₂O
Element number of atoms atomic mass TOTAL
Na 1 x 22.99g/mol = 22.99g/mol
O 1 x 16.00g/mol = 16.00g/mol
H 1 x 1.01g/mol =<u> 1.01g/mol</u>
40.00g/mol
This means that the molecular mass of NaOH is 40.00 g/mol
Then we use this to convert 35.0g of NaOH to moles:
Now that you have the number of moles we divide it by the solution in liters. Before we can do that you have to conver 100ml to L.
Then we divide it:
2. 20.0g CuCl₂ in 350ml H₂O
Element number of atoms atomic mass TOTAL
Cu 1 x 63.55g/mol = 63.55g/mol
Cl 2 x 34.45g/mol = <u>70.90g/mol</u>
134.45g/mol
350ml = 0.350L
3. 3.35g CaCO₃ in 500ml
Element number of atoms atomic mass TOTAL
Ca 1 x 40.08g/mol = 40.08g/mol
C 1 x 12.01g/mol = 12.01g/mol
O 3 x 16.00g/mol =<u> 48.00g/mol</u>
100.09g/mol
500ml = 0.5L
Answer:
There are 122 one dollar bills, 11 five dollar bills and 5 ten dollar bills.
Step-by-step explanation:
There are bills of one dollar, five dollars and ten dollars on the cash drawer, therefore the sum of all of them multiplied by their respective values must be equal to the total amount of money on the drawer. We will call the number of one dollar bills, five dollar bills and ten dollar bills, respectively "x","y" and "z", therefore we can create the following expression:
We know that there are six more 5 dollar bills than 10 dollar bills and that the number of 1 dollar bills is two more than 24 times the number of 10 dollar bills, therefore:
Applying these values on the first equation, we have:
Applying z to the formulas of y and x, we have:
There are 122 one dollar bills, 11 five dollar bills and 5 ten dollar bills.