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3 years ago

What do measurements of the mass of the Milky Way indicate?

1 answer:

8 0

<span>That the mass is far lesser and distributed mistakenly, as compared to what the orbits of stars declare it should be. Stars orbit more rapidly than the mass would predict, particularly out toward the galactic edge. This means that there is more mass than has been measured, and that it is spread out in a huge cloud around the galaxy. This is one of the reasons why scientists believe that dark matter exists.</span>

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A 45 mL sample of nitrogen gas is cooled from 135ºC to 15C in a container that can contract or expand at constant pressure. Wha

Vanyuwa [196]

Answer:

V₂ =31.8 mL

Explanation:

Given data:

Initial volume of gas = 45 mL

Initial temperature = 135°C (135+273 =408 K)

Final temperature = 15°C (15+273 =288 K)

Final volume of gas = ?

Solution:

The given problem will be solve through the Charles Law.

According to this law, The volume of given amount of a gas is directly proportional to its temperature at constant number of moles and pressure.

Mathematical expression:

V₁/T₁ = V₂/T₂

V₁ = Initial volume

T₁ = Initial temperature

V₂ = Final volume

T₂ = Final temperature

Now we will put the values in formula.

V₁/T₁ = V₂/T₂

V₂ = V₁T₂/T₁

V₂ = 45 mL × 288 K / 408 k

V₂ = 12960 mL.K / 408 K

V₂ =31.8 mL

8 0

2 years ago

A 85.2 g copper bar was heated to 221.32 degrees Celsius and placed in a coffee cup calorimeter containing 4250 mL of water at 2

Assoli18 [71]

Answer:

The specific heat of copper is 0.385 J/g°C

Explanation:

A 85.2 g copper bar was heated to 221.32 degrees Celsius and placed in a coffee cup calorimeter containing 425 mL of water at 22.55 degrees Celsius. The final temperature of the water was recorded to be 26.15 degrees Celsius. What is the specific heat of the copper?

Step 1: Data given

Mass of copper = 85.2 grams

Temperature of copper = 221.32 °C

Volume of water = 425 mL

Temperature of water = 22.55 °C

Final temperature = 26.15 °C

Specific heat of water = 4.184 J/g°C

Step 2: Calculat the specific heat of copper

Heat lost = heat gained

Q = m*c*ΔT

Qcopper = -Qwater

m(copper)*c(copper)*ΔT(copper) = - m(water) * c(water) * ΔT(water)

⇒ m(copper) = 85.2 grams

⇒ c(copper) = TO BE DETERMINED

⇒ ΔT(copper) = the change in temeprature = T2 -T1 = 26.15 -221.32 = -195.17 °C

⇒ m(water) = The mass of water = 425 mL * 1g/mL = 425 grams

⇒ c(water) = The specific heat of water = 4.184 J/g°C

⇒ ΔT(water) = The change of temperature of water = 26.15 - 22.55 = 3.6

85.2 * c(copper) * (-195.17) = -425 * 4.184 * 3.6

c(copper) = 0.385 J/g°C

The specific heat of copper is 0.385 J/g°C

(Note, The original question says the volume of the water is 4250 mL. IF this is not an error, the specific heat of copper is 3.85 J/g°C (10x higher than the normal value).

8 0

2 years ago

Definition: This is a change in velocity per time.

ladessa [460]

Answer: acceleration

a = 5.36 m/s²

Explanation: solution attached:

Convert first 60 mi/h to m/s

Use the formula for acceleration

a = vf - vi /t

8 0

2 years ago

I MARK AS BRAINLIEST IF YOU ANSWER QUICK!

Sedaia [141]

Answer:

Earth's average albedo is about 0.3. In other words, about 30 percent of incoming solar radiation is reflected back into space and 70 percent is absorbed. A sensor aboard NASA's Terra satellite is now collecting detailed measurements of how much sunlight the earth's surface reflects back up into the atmosphere.

Explanation:

hope this helps :)

5 0

2 years ago

Draw the mechanism for the acid-catalyzed reaction of acetic acid (ethanoic acid) with the methanol to yield methyl acetate (met

timama [110]

When ethanoic acid react with methanol in the presence of H⁺ or heat it gives methyl ethanoate and water.

<h3>What is Balanced Chemical Equation ?</h3>

The balanced chemical equation is the equation in which the number of atoms on the reactant side is equal to the number of atoms on the product side in an equation.

Now write the chemical equation

CH₃COOH + CH₃OH ⇄ CH₃COOCH₃ + H₂O

Here

CH₃COOH is Ethanoic acid (Acetic acid)

CH₃OH is Methanol (Methyl Alcohol)

CH₃COOCH₃ is Methyl ethanoate (Methyl Acetate)

H₂O is water

Thus from the above conclusion we can say that When ethanoic acid react with methanol in the presence of H⁺ or heat it gives methyl ethanoate and water.

Learn more about the Balanced Chemical Equation here: brainly.com/question/26694427

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3 0

1 year ago