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3 years ago

Test Name: GR8_Sci_U07_USA_FY20

Chemistry

1 answer:

kumpel [21]3 years ago

8 0

The distance from the star to the Earth

Explanation:

The absolute brightness of a star is a measure of the intrinsec luminosity of the star, i.e. it does not depend on the distance of the star from the Earth.

In other word, the absolute brightness is a measure of the luminosity of a star if all stars were placed at the same distance from Earth.

On the other hand, the relative brightness of a star is a measure of its luminosity as observed on Earth, therefore it does depend on the distance of the star from the Earth: the farther the star is, the more its luminosity will decrease, and vice-versa.

The star's absolute brightness, therefore, depends only on the characteristics of the star itself, namely:

- The absolute magnitude of the star

- The rate at which the star produces energy via nuclear fusion

- The rate at which the star releases energy via electromagnetic radiation

Therefore, the only factor that does NOT change if the absolute brightness of a star changes is

- The distance from the star to the Earth

Learn more about planets and stars:

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A balloon contains a 10% glucose solution. The balloon is permeable to water but not to glucose. A beaker contains a 5% glucose

deff fn [24]

The state of the balloon:

When the balloon is submerged in the beaker, the amount of water in the beaker will get reduced.

What is Osmosis:

Based on the concentration of solutes on both sides of the membrane, water will flow through a permeable membrane in a specific direction.

Hypertonic solution:

It means that there are more solutes present in the surrounding environment than in the cell itself.

Hypotonic solution:

In a hypotonic solution, the concentration of solutes inside the cell is higher than that outside the cell.

When comparing two solutions, the one with the larger solute concentration is hypertonic, and the one with the lower solute concentration is hypotonic. Isotonic solutions have an identical solute concentration.

While the solution in the beaker is hypertonic, Meaning that will draw water molecules out of the cell. As water molecules move from a location of high water potential (dilute solution) to a region of reduced water potential (10% glucose solution), the water from the 5% glucose solution will flow into the 10% one (concentrated solution)
This is the reason why the amount of water decreases when the balloon is submerged in the beaker.

Learn more about the glucose solution and permeability here,

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7 0

1 year ago

What is the net amount of energy released when one mole of h2o(?) is produced?

german

The net amount of energy produced can be obtained from a table of enthalpy change of formation, available online.

The enthalpy change of formation indicate how much energy the 1 mole of the product (H2O) has relative to the elemental reactants (H2 and O2). In other words, the "lost" energy equals the heat/energy released.

For water (H2O), this value is -285.8 if the final product is a liquid under standard conditions, and -241.82 if the product is in gas form which contains some energy that could be further released. This means that if the final product (H2O) is in liquid form, energy released is 285.8 kJ/mol.

Since water is in liquid form under standard conditions, the first value (285.8 kJ/mol) is generally appropriate.

7 0

3 years ago

Ethan pushes a wooden box across a carpeted floor. Then he pushes the same box across a smooth marble floor. Why does Ethan find

Sholpan [36]

Because there is less friction on the marble floor.

3 0

2 years ago

Nitric acid can be produced by the reaction of gaseous nitrogen dioxide with water. 3 no2(g) + h2o(ℓ) −→ 2 hno3(ℓ) + no(g) if 85

Naya [18.7K]

The balanced equation for the above reaction is as follows;
3NO₂ + H₂O --> 2HNO₃ + NO
stoichiometry of NO₂ to NO is 3:1
molar volume is where 1 mol of any gas occupies a volume of 22.4 L
volume of gas is directly proportional to number of moles of gas.
therefore stoichiometry can be applied for volume as well.
volume ratio of NO₂ to NO is 3:1
volume of NO₂ reacted - 854 L
therefore volume of NO formed - 854 L /3 = 285 L
volume of NO formed - 285 L

8 0

2 years ago

PLEASE HELPPPPP I WILL GIVE BRAINLEST FOR WHOEVER FINDS THE ANSWER!!!

Elza [17]

I think that it is shear adhesion

5 0

2 years ago

Read 2 more answers