if .40 L if water is added to the volume of cup 3, what would be the new molarity of a 2 M solution of kool-aid

Chemistry

1 answer:

stiks02 [169]3 years ago

8 0

Answer:

0.7692 M ≅ 0.77 M.

Explanation:

It is known that the no. of millimoles of a solution before dilution is equal to the no. of millimoles of the solution after the dilution.

It can be expressed as:

(MV) before dilution = (MV) after dilution.

M before dilution = 2.0 M, V before dilution = 0.25 L.

M after dilution = ??? M, V after dilution = 0.25 L + 0.40 L = 0.65 L.

∴ M after dilution = (MV) before dilution/(V) after dilution = (2.0 M)(0.25 L)/(0.65 L) = 0.7692 M ≅ 0.77 M.

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which of these pieces of equipment would be the most appropriate for precisely measuring 29 mL of liquid? Explain your reasoning

Anna007 [38]

Answer:

The best equipment would be the graduated cylinder. Why?

Firstly, the smallest marking on the graduated cylinder is 2 mL, while on all the others the smallest marking is way above that, like 25 mL and 100 mL.

Without even going into the details, we can first rule out the volumetric flask, since its smallest marking is 100 mL and even that is already bigger than our sample size, hence we would have no markings to accurately measure out 29 mL of our sample had we used the volumetric flask.

Next to be ruled out would be the Erlenmeyer flask, as you can see in the image, it only has three marking, and as the smallest marking is 25 mL, each marking is at least 25 mL, and even so far as going up to 50 mL. This cannot let us accurately measure 29 mL out at all, due to the markings being way too big to do that. Hence, the Erlenmeyer flask is ruled out.

Finally, the beaker seems to be a worthy candidate! Unfortunately, for the same reason as the Erlenmeyer flask, as you can see in the image each marking represents 10 mL. We cannot measure 9 mL in the beaker accurately, and hence the beaker is ruled too.

We are left with the graduated cylinder, and that is our answer.

Explanation:

Hope this helped!

5 0

3 years ago

A person of 82 kg is in an elevator. If the elevator is moving at a speed of 5m/s, what’s the person’s kinetic energy.

andre [41]

Answer:

The person’s kinetic energy is 1,025 J

Explanation:

Kinetic energy is a form of energy. It is defined as the energy associated with bodies that are in motion and this energy depends on the mass and speed of the body.

Kinetic energy is defined as the amount of work necessary to accelerate a body of a given mass and in a position of rest, until it reaches a given speed. Once this point is reached, the amount of accumulated kinetic energy will remain the same unless there is a change in speed or the body returns to its state of rest by applying a force.

Kinetic energy is represented by the following formula:

$Ec=\frac{1}{2}*m*v^{2}$

where Ec is kinetic energy, which is measured in Joules (J), m is mass measured in kilograms (kg), and v is velocity measured in meters over seconds (m/s).

In this case: