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Olegator [25]
3 years ago
9

You need to make a very dilute solution of sodium phosphate dihydrate (MW 142 g/mol, FW 178 g/mol). How many grams of sodium pho

sphate dihydrate do you need to make 500 mL of a 2 M stock solution? How many mL of the stock solution do you need to make 100 mL of a 5 mM solution?
Physics
1 answer:
dlinn [17]3 years ago
6 0

Answer:

first question is 178 g of sodium phosphate dihydrate. second question is 0.25 mL

Explanation:

To know the number of grams from the number of moles (0.5L*2mol/L)= 1mol. 1 mol is equal to 178 g. Second question mL of the stock is obtained from (0.1L*5.0^-3mol/L)/2mol/L.

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otez555 [7]

Answer:

Visible Light

wavelength = 4000 - 7000 Angstroms = 400 - 700 milli-microns

1 A unit =  10^-10 m

1 mμ = 10^-9 m

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2 years ago
What happens to a sound wave when it interferes with another sound wave having the same frequency but traveling in the opposite
Zolol [24]

its called destructive interference.


8 0
3 years ago
Read 2 more answers
A spaceship ferrying workers to Moon Base I takes a straight-line path from the earth to the moon, a distance of 384,000 km. Sup
Tema [17]

Answer:

a) v = 19,149.6 m/s

b) f = 95%

c) t = 346.5min

Explanation:

First put all values in metric units:

15.8 min*\frac{60s}{1min}=948s

The equation of motion you need is:

v_f = a*t+v_0

where v_f is the final velocity, a is acceleration and t is time in hours.

Since the spaceship starts from 0 velocity:

v_f = a*t = 20.2*948 = 19,149.6 m/s

Next, you need to calculate the distances traveled on each interval, considering that both starting and final intervals travel the same distance because the acceleration and time are equal. For this part you need the next motion equation:

x=\frac{v_0+v_f}{2}t

solving for first and last interval:

Since the spaceship starts and finish with 0 velocity:

x=\frac{v}{2}t=\frac{19,149.6}{2}948=9,076,910.4m=9,076.9104km

Then the ship traveled 384,000-9,076.9104*2 = 361,846.1792km at constant speed, which means that it traveled:

f_{constant_speed} =\frac{ x_{constant_speed}}{x_total} =\frac{361,846.1792}{380,000} =0.95

Which in percentage is 95% of the trip.

to calculate total time you need to calculate the time used during constant speed:

t = \frac{361,846,179.2}{19,149.6} = 18,895.75s = 314min

That added to the other interval times:

t_{total} = t_1+t_2+t_3=15.8+314.93+15.8=346.5min

5 0
2 years ago
A heat pump absorbs heat from the atmosphere at a rate of 30 kW. If work is being done to run this heat pump at a rate of 7.7 kW
Volgvan

Answer:

Option D 3.9

Explanation:

First, you need to use the correct equation which is the following:

COP = Q/W

Where:

Q = heat absorbed

W = work done by the pump

COP = coefficient of perfomance

We have all the data, so, all you need to do is replace in the above expression and you shoould get the correct result:

COP = 30 / 7.7

COP = 3.896

This result you can round it to 3.9. option D.

8 0
3 years ago
If the volume of a sample of gas is reduced at constant temperature, the average velocity of the molecules _______, the average
VLD [36.1K]

Answer:

Explanation:

If the volume of a sample of gas is reduced at constant temperature, the average velocity of the molecules increases, the average force of an individual collision increases, and the average number of collisions with the wall, per unit area, per second increases.

As volume is reduced, the gas molecules come closer together, which increases the number of collisions between them and their collisions with the container walls. Also, since the distance traveled by each molecule between successive collision decreases, the molecule velocity doesn't decrease much within collisions as a result of which, the average velocity is higher compared to when the gas is stored in a larger volume. Finally, due to constant collisions, the direction of molecule travel changes rapidly owing to which the acceleration of molecules increases.

6 0
3 years ago
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