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3 years ago

Find the energy of a photon of light if the wavelength of the light wave is 6.88 x 10–7m

1 answer:

6 0

Use the formula E=hv, h=plancks constant and v=frequency
use the formula c=v*lambda to find v
the answer will be 2.88*10^-23J

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Which of the following substances would you expect to have a low melting point?

Lorico [155]

The substance you would expect to have a low melting point would be carbon dioxide, so the correct answer would be A

5 0

3 years ago

Liquid nitrogen has a density of 0.808 g/mL and boils at 77 K. Researchers often purchase liquid nitrogen in insulated 195-L tan

Reika [66]

Answer:

The nswer to the question is

The maximum fraction of the air in the room that could be displaced by the gaseous nitrogen is 0.548 or 54.8 %

Explanation:

To solve the question we note that

The density of the liquid nitrogen = 0.808g/mL and the volume is 195 L tank (vaporised)

Therefore since density = mass/volume we have

mass = Density × volume = 0.808 g/mL × 195 L × 1000 ml/L =157560 g

In gaseous form the liquid nitrogen density =1.15 g/L

That is density = mass/volume and volume = mass/density = 157560 g/(1.15g/L) or

volume = 137008.69565 L

The dimension of the room = 10 m × 10 m × 2.5 m = 250 m³ and

1 m³ is equivalent to 1000 L, therefore 250 m³ = 250 m³ × 1000 L/m³ = 250000L

Therefore fraction of the volume occupied by the gaseous nitrogen =

137008.69565 L/250000 L = 0.548

Therefore the gaseous nitrogen occpies 54.8% of the room

7 0

3 years ago

Sarah added sugar to her iced tea but it is not dissolveing very quickly which can Sarah do to make the sugar dissolve faster ?

Aliun [14]

Stir it,
Or as warmer water makes solutes dissolve faster Sarah can do that

7 0

3 years ago

Analysis of the water content of a lake found in the desert showed that it contained 17.5 percent chloride ion, and has a densit

tankabanditka [31]

Answer:

The molarity is 6.0 M.

Explanation:

The concentration of a solution is the amount of solute present in a given amount of solvent, or a given amount of solution.

In this problem, we are asked to convert percent by mass to molarity, which are two different concentration units.

The percent by mass is the ratio of the mass of a solute to the mass of the solution, multiplied by 100 percent. On the other hand, molarity (M) is defined as the number of moles of solute per liter of solution.

If we have 17.15 percent chloride ion, that means that we have 17.15 grams of chloride ion in 100 grams of solution. The density provided is the density of the solution, so we calculate how many mL correspond to 100 grams of solution:

1.23 g ----------- 1 mL

100 g ------------ x= 81.3 mL

Therefore, 17.5 grams of chloride ion are contained in 81.3 mL. Now we need to convert these grams into moles.

The atomic mass of chlorine is 35.5 g/mol:

35.5 g --------------- 1 mol

17.5 g --------------- x= 0. 49 mol

This 0.49 moles are contained in 81.13 mL, the definition of molarity says that this moles are contained in a liter (or what is the same, 1000 mL):

81.3 mL --------------- 0.49 mol

1000 mL ------------- x= 6.0 M

The molarity of the chloride ion will be 6.0 M.

5 0

3 years ago

Four samples of gas each exert 675 mm Hg in separate 3.5 L containers. What pressure will they exert if they are all placed in a

DedPeter [7]

The pressure that will be exerted if four sample of gas are placed in a single 3.5 container is calculated as below

if each gas occupies 675 mmhg

what about 4 gases in the sample
by cross multiplication

= 675 mm hg x 4/1 = 2.7 x10^3mmhg (answer D)

3 0

3 years ago