All categories

2 years ago

Test Name: GR8_Sci_U07_USA_FY20

Chemistry

1 answer:

kumpel [21]2 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:

brainly.com/question/2887352

brainly.com/question/10934170

#LearnwithBrainly

You might be interested in

Can somebody answer this question for me it might be easy for you answer part 1,2,and 3

jonny [76]

Answer:

hey love! what is the question??

8 0

2 years ago

Read 2 more answers

A chef is serving a lunch special with 1 sandwich and 2 corn cobs per plate. If there are 5 sandwiches and 14 corn cobs, what is

shtirl [24]

5 plates is the highest amount that can be served

There’s only 5 sandwiches so 7 is automatically ruled out, there’s 14 corn cobs and 5 sandwiches only need 10 so it works out

7 0

3 years ago

Read 2 more answers

A chemist designs a galvanic cell that uses these two half-reactions: half-reaction standard reduction potential (s)(aq)(aq)(l)

miv72 [106K]

Answer:

Reduction (cathode): Cu²⁺(⁺aq) + 2 e⁻ → Cu(s)

Oxidation (anode): Zn(s) → Zn²⁺(⁺aq) + 2 e⁻

Cu²⁺(⁺aq) + Zn(s) → Cu(s) + Zn²⁺(⁺aq)

E°cell = 1.10 V

Explanation:

The half-reactions are missing, but I will propose some to show you the general procedure and then you can apply it to your equations.

Suppose we have the following half-reactions.

Cu²⁺(⁺aq) + 2 e⁻ → Cu(s) E°red = 0.34 V

Zn²⁺(⁺aq) + 2 e⁻ → Zn(s) E°red = -0.76 V

To identify how to make a spontaneous cell, we need to consider the standard reduction potentials (E°red). The half-reaction with the higher E°red will occur as a reduction (in the cathode), whereas the one with the lower E°red will occur as an oxidation (in the anode).

Reduction (cathode): Cu²⁺(⁺aq) + 2 e⁻ → Cu(s) E°red = 0.34 V

Oxidation (anode): Zn(s) → Zn²⁺(⁺aq) + 2 e⁻ E°red = -0.76 V

To get the overall equation we add both half-reactions.

Cu²⁺(⁺aq) + Zn(s) → Cu(s) + Zn²⁺(⁺aq)

The standard cell potential (E°cell) is the difference between the standard reduction potential of the cathode and the standard reduction potential of the anode.

E°cell = E°red, cat - E°red, an

E°cell = 0.34 V - (-0.76 V) = 1.10 V

Since E°cell > 0, the reaction is spontaneous.

5 0

2 years ago

What is the enclosure act

VashaNatasha [74]

The Inclosure Acts, which use an old or formal spelling of the word now usually spelt "enclosure", cover enclosure of open fields and common land in England and Wales, creating legal property rights to land previously held in common.

4 0

2 years ago

A 0.2722 g sample of a pure carbonate, X n CO 3 ( s ) , was dissolved in 50.0 mL of 0.1200 M HCl ( aq ) . The excess HCl ( aq )

Alex73 [517]

Answer:

0.00369 moles of HCl react with carbonate.

Explanation:

Number of moles of HCl present initially = $\frac{0.1200}{1000}\times 50.0$ moles = 0.00600 moles

Neutralization reaction (back titration): $NaOH+HCl\rightarrow NaCl+H_{2}O$

According to above equation, 1 mol of NaOH reacts with 1 mol of 1 mol of HCl.

So, excess number of moles of HCl present = number of NaOH added for back titration = $\frac{0.0980}{1000}\times 23.60$ moles = 0.00231 moles

So, mole of HCl reacts with carbonate = (Number of moles of HCl present initially) - (excess number of moles of HCl present) = (0.00600 - 0.00231) moles = 0.00369 moles

Hence, 0.00369 moles of HCl react with carbonate.

3 0

2 years ago