On an as yet undiscovered planet, the atmo-
sphere is composed of a mixture of 79% argon
and 20% oxygen (volume percentage) along
with trace amounts of other gases, including
CO2, Kr, and Ne. An enterprising student on
that planet wishes to sell the equivalent of he-
lium balloons to small children. Heliun is not
available.
Which of the gases
1) krypton
II) carbon dioxide
III) methane
IV) propane
V) nitrogen
VI) carbon monoxide
would be an acceptable replacement so that
the balloons will float in that atmosphere?

Water is constantly being cycled between the atmosphere, the ocean and the land. This cycling is a very important process that helps sustain life on Earth. When the sun heats water, the water evaporates or changes to water vapor. Water vapor rises and condenses or changes back into liquid water droplets.

Answer: 8 oxygen atoms and 4 hydrogen atoms. Explanation down below.

Explanation: One molecule of oxygen gas is composed of two oxygen atoms (O2). Here there is four atoms of oxygen gas which in total gives eight oxygen atoms. Same ways One molecule of hydrogen gas is composed of two hydrogen atoms (H2), so 2 atoms of hydrogen gas in total gives four hydrogen atoms. As per the formula of water, 2 (H2) and 1(O) to form a water molecule (H2O). Here there are 4 H2, so divide the number of hydrogen atoms by the number needed per water molecule i.e. 4 / 2 = 2. This means 2 water molecules will be produced.

Answer:

Option B

Explanation:

We will check the solubility graph for potassium nitrate,  KNO 3. Based on the graph it can be said that the temperature of solution when 130 grams of KNO3 dissolves in 100 grams of water is near to 65 degree Celsius. Now if three grams of solute is increased then the temperature of the solution will increase by a degree or so and hence the most probable temperature would be 68 degree Celsius.

Hence, option B is correct

Answer:

B. 68 Celsius

Explanation:

Answer:

A: catalyst

Explanation:

In Chemistry, the rate of reaction of chemical elements (reactants) can be sped to produce a chemical compound or elements (products), through the addition of a catalyst that is unaffected by the reaction.

This ultimately implies that, to speed up a chemical reaction, add a catalyst that is unaffected by a reaction.

For example, an enzyme refers to a biological catalyst that is typically used to speed up (accelerate) the rate of a chemical reaction by lowering the activation energy of its reactants.

An enzyme can be defined as a biological catalyst that typically lowers the activation energy of a biological reaction. When the activation energy of a reaction is low, the rate of the reaction would be faster. Therefore, an enzyme speeds or catalyzes the rate of a reaction by lowering its activation energy.

Generally, an increase in temperature increases or speeds up the rate of a reaction while low temperature limits or reduces the rate of a reaction. The optimal temperature for enzymes in the human body is around 37 degrees celsius.

Answer:

no of moles = given mass/molar mass

no of moles = 10/169.87 =0.058moles

molarity = number of moles of solute/volume of solution in litre

molarity = 0.058/5

molarity = 0.0116

Answer:

b

sorry if wrong

Explanation:

Answer:

C

Explanation:

In the presence of a catalyst, both the forward and reverse reaction rates will speed up equally. :)

Answer:

yeah they dream in weird shapes mostly I think. unless they weren't born blind then they dream normally I think

Answer:

Kind of, our dreams refer to what we see, but blind people can't see, they might have dreams what the world might look like

Answer:

Fe(s) + Cu2+(aq) ===> Fe2+(aq) + Cu(s)

Answer:

2CuFeS2+2SiO2+4O2→Cu2S+2FeSiO3+3SO2(1)

Explanation:

2CuFeS2+2SiO2+4O2→Cu2S+2FeSiO3+3SO2(1)

Answer:

Explanation:

The moon

Answer:

966.4mL

Explanation:

Using the combined gas equation as follows:

P1V1/T1 = P2V2/T2

Where;

P1 = initial pressure

P2 = final pressure

V1 = initial volume

V2 = final volume

T1 = initial temperature (K)

T2 = final temperature (K)

According to this question, the following information were provided:

P1 = 998mmHg

P2 (STP) = 760mmHg

V1 = 806mL

V2 = ?

T1 = 26°C = 26 + 273 = 299K

T2 (STP) = 273K

P1V1/T1 = P2V2/T2

998 × 806/299 = 760 × V2/273

804388/299 = 760V2/273

2690.26 = 760V2/273

760V2 = 2690.26 × 273

760V2 = 734440.98

V2 = 734440.98 ÷ 760

V2 = 966.4mL

Answer:

Most of the water doesn't come from the ocean, it comes from fresh water sources

Explanation:

Hope you have a great day :)

Answer:Gravity and inertia

Answer:

New energy level is n = 2

Explanation:

ΔE = energy released by e⁻ transition n = 7 to n(final) = - h·c/λ

h = Planck's Constant = 6.63 x 10⁻³⁴ j·s

c = speed of light in vacuum = 3 x 10⁸ m/s

λ = wavelength = 397 nm = 3.97 x 10⁻⁷ m

ΔE = - (6.63 x 10⁻³⁴j·s )(3 x 10⁸ m/s)/(3.97 x 10⁻⁷ m) = - 5.01 x 10⁻¹⁹ joule

Note: this is the transitional energy 'released' by the electron moving from n = 7 energy level to n(final) energy level. As released energy, the system should be represented by an exothermic process hence, the negative value for ΔE = - h·c/λ. The equivalent amount of energy is an absorption of electromagnetic energy (EMR) to promote the electron from n(final) to n = 7 and this would be endothermic as noted with a +h·c/λ .

The Bohr Model of the electron behavior postulates electron transitions by the release of a 'discrete' amount of EMR as emission spectra defined by the expression ...

ΔE = E(final) - E(initial) => E(final) = ΔE + E(initial)

E(n) = positional (potential) energy content of electron while in energy level n and is defined by the expression E(n) = -R(H)/n²

R(H) = Rydberg Constant = 2.18 x 10⁻¹⁸ joules

n = positional energy level (in this case) = 7

E₇ = -2.18 x 10⁻¹⁸ j / (7)² = -4.45 x 10⁻²⁰ j (potential energy of n = 7 electron)

E(final) = ΔE + E₇ = (-5.01 x 10⁻¹⁹ j)  + (-4.45 x 10⁻²⁰ j) = -4.455 x 10⁻¹⁹ j

E(final) = -R(H)/n²

=> n = SqrRt[R(H)/E(final)] = SqrRt[(-2.18 x 10⁻¹⁸ j)/(-4.455 x 10⁻¹⁹)] ≅ 2

New energy level is n = 2

Answer:

I believe it is C2H5OH

Explanation:

hopefully it's right

Answer:

killer T-cell find and destroy infected cells that have been turned into virus-making factories

Answer:

Answers of the greenhouse effect 1 ,3 and 4

Answer:

D - Hydroxide Ion (OH-)

Explanation:

A base provides either hydroxide ions (OH–) or other negatively charged ions that combine with hydrogen ions, reducing their concentration in the solution and thereby raising the pH. In cases where the base releases hydroxide ions, these ions bind to free hydrogen ions, generating new water molecules.

Answer:

Outside air

Nose

Lungs

Bloodstream

Cell

Explanation:

We breathe in oxygen from the outside air in through our nose and it travels to our lungs. Inside our lungs, we have Avioli's that diffuse oxygen into our bloodstream and the bloodstream helps the oxygen travel into our cells.

Hope this helps :)

Respiration is the process of exchange of gases between the cell and atmosphere. The path of respiration involves Outside Air⇒  Nose⇒ Lungs⇒ Bloodstream⇒ Cell.

Respiration is the movement of oxygen from the outside environment to the cells and the removal of carbon dioxide from the cells into the outside environment.

Respiration is of two types depending upon the presence of oxygen:

1. Aerobic Respiration: This takes place in the presence of oxygen

2. Anaerobic Respiration: This takes place in the absence of oxygen.

The path of respiration includes inspiration of outside air into the nose, through the nostrils this air is passed on to the lungs. The alveoli is the site of gaseous exchange in the lungs. In the lungs, oxygen is inspired and carbon dioxide is expired.

The oxygen gas which is inspired by the lungs is dissolved in the blood. Oxygen forms a complex with the hemoglobin protein present in the blood. This blood is then circulated to all the cells and tissues of body. Thus, the oxygen is supplied to all the cells and tissues. The path includes Outside Air⇒  Nose⇒ Lungs⇒ Bloodstream⇒ Cell.

Learn more about Respiration here:

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Answer:

b, decrease in movement of the molecules

Explanation:

removing the energy will begin making the molecules lock up and stop moving due to the loss of energy.

hope this helped

The scientist who wrote the universal law of gravitation was Sir Isaac Newton.

The scientist that wrote the universal law of gravitation was Isaac Newton.

The universal law of gravitation states that every object in this universe attracts every other object around it with a force, whose magnitude is directly proportional to the product of their masses and indirectly proportional to the square of the distance between them.

The universal law of gravitation was first published by the scientist Issac Newton in the year 1687.

Learn more about force here:

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Answer:  54.8 Liters of hydrogen gas can be made at 300 K and 0.970 atm

Explanation:

To calculate the moles, we use the equation:

[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text {Molar mass}}[/tex]

[tex]\text {moles of magnesium }=\frac{52.0g}{24g/mol}=2.16moles[/tex]

The balanced chemical equation is:

[tex]Mg+2HCl\rightarrow MgCl_2+H_2[/tex]

According to stoichiometry:

1 mole of Mg gives = 1 mole of [tex]H_2[/tex]

Thus 2.16 moles of Mg give = [tex]\frac{1}{1}\times 21.6=2.16 moles[/tex] of [tex]H_2[/tex]

According to ideal gas equation:

[tex]PV=nRT[/tex]

P = pressure of gas = 0.970 atm

V = Volume of gas = ?

n = number of moles = 2.16

R = gas constant =[tex]0.0821Latm/Kmol[/tex]

T =temperature =[tex]300K[/tex]

[tex]V=\frac{nRT}{P}[/tex]

[tex]V=\frac{2.16mol\times 0.0821Latm/Kmol\times 300K}{0.970atm}=54.8L[/tex]

Thus 54.8 Liters of hydrogen gas can be made at 300 K and 0.970 atm

Answer:

Boyle's Law

Explanation:

"Boyle's law, also referred to as the Boyle–Mariotte law, or Mariotte's law, is an experimental gas law that describes how the pressure of a gas tends to increase as the volume of the container decreases."

                                          -Wikipedia

Answer:

Because of the solubility of ammonia gas in water, it is not collected over water.

Explanation:

Gases prepared in the laboratory are often collected by a technique called water displacement. A bottle is filled with water and placed upside-down in a trough or container of water. The reaction flask is connected to the bottle of water by means of a rubber or glass tubing which is fed under the water bottle . As the gas is produced in the reaction flask, it enters the bottle and displaces the water in it. When the bottle is full of the gas, it is then sealed. The volume of gas in the bottle can be used to determine the amount of gas produced in the reaction. Usually, the gas collected is present in addition to water vapor in the bottle.

Gases that are collected over water must not react with or dissolve in water.

Ammonia gas is very soluble in water. The solubility is due to the readiness with which it forms hydrogen bonds with water to produce aqueous ammonia, NH₃.H₂O.

Aqueous ammonia ionizes partially to produce ammonium ions, NH₄+ and hydroxide ions, OH-. Because of the solubility of ammonia gas in water, it is not collected over water.