If there is a third-quarter moon on July 2 , what is the approximate date of the next full moon?

A chemist must prepare 400 mL of 1.00M aqueous aluminum sulfate working solution. He'll do this by pouring out 1.82 mol/L aqueou

Digiron [165]

Answer:

219.78 mL of the stock solution are needed

Explanation:

First, we take a look at the desired Al2(SO4)3 working solution. We are told that the we need 400 mL of an aqueous aluminum sulfate solution 1.0 M. Let's see how many moles of the compound we have in the desired volume:

1000 mL Al2(SO4)3 solution ----- 1 mole of Al2(SO4)3

400 mL Al2(SO4)3 solution ----- x = 0.4 moles of Al2(SO4)3

To reach the desired concentration in the working solution we need 0.4 moles of Al2(SO4)3 in 400 mL, so we calculate the volume of the stock solution needed to prepare the working solution:

1.82 moles Al2(SO4)3/L = 1.82 M → This is the molar concentration of the stock solution.

1.82 moles of Al2(SO4)3 ----- 1000 mL

0.4 moles of Al2(SO4)3 ----- x = 219.78 mL

So, if we take 219.78 mL of the 1.82 M stock solution, we put it in a graduated cylinder and we dilute it to 400 mL, we would obtain a 1.0 M Al2(SO4)3 solution.

4 0

3 years ago

Read 2 more answers

Energy has both wavelength and particle-like properties, but electrons have only particle like properties, true or false

dangina [55]

False bc both energy and electrons have both wave and particle like properties. :)

4 0

3 years ago

An atom of 125Sn has a mass of 124.907785 amu. Calculate the binding energy in MeV per atom. Use the masses: mass of 1H atom = 1

Ksenya-84 [330]

Answer:

1.06×10³ MeV/atom

Explanation:

Atomic number : It is defined as the number of electrons or number of protons present in a neutral atom.

Also, atomic number of Sn = 5 0

Thus, the number of protons = 50

Mass number is the number of the entities present in the nucleus which is the equal to the sum of the number of protons and electrons.

Mass number = Number of protons + Number of neutrons

125 = 50 + Number of neutrons

Number of neutrons = 75

Mass of neutron = 1.008665 amu

Mass of proton = 1.007825 amu

Calculated mass = Number of protons*Mass of proton + Number of neutrons*Mass of neutron

Thus,

Calculated mass = (50*1.007825 + 75*1.008665) amu = 126.041125 amu

Given mass = 124.907785 amu

Mass defect = Δm = |126.041125 - 124.907785| amu = 1.13334 amu

The conversion of amu to MeV is shown below as:-

1 amu = 931.5 MeV

So, Energy = 1.13334*931.5 MeV/atom = 1.06×10³ MeV/atom

3 0

3 years ago

Cobalt-60 is a strong gamma emitter that has a half- life of 5.26 yr. The co balt-60 in a radiotherapy unit must be replaced whe

Alenkasestr [34]

Answer: The sample of Cobalt-60 isotope must be replaced in January 2027

Explanation:

The equation used to calculate rate constant from given half life for first order kinetics:

$t_{1/2}=\frac{0.693}{k}$

where,

$t_{1/2}$ = half life of the reaction = 5.26 years

Putting values in above equation, we get:

$k=\frac{0.693}{5.26yrs}=0.132yrs^{-1}$

Rate law expression for first order kinetics is given by the equation:

$k=\frac{2.303}{t}\log\frac{[A_o]}{[A]}$

where,

k = rate constant = $0.132yr^{-1}$

t = time taken for decay process = ? yr

$[A_o]$ = initial amount of the sample = 100 grams

[A] = amount left after decay process = (100 - 75) = 25 grams

Putting values in above equation, we get:

$0.132=\frac{2.303}{t}\log\frac{100}{25}\\\\t=10.5yrs$

The original sample was purchased in June 2016

As, June is the 6th month of the year, which means the time period will be $2016+\frac{6}{12}=2016.5$

Adding the time in the original time period, we get:

$2016.5+10.5=2027$

Hence, the sample of Cobalt-60 isotope must be replaced in January 2027

3 0

3 years ago

Which arrow represents the change of state described

Mama L [17]

Answer:N

Explanation:

6 0

3 years ago