(g) How does the colour of a star help to find its age?

Answers

Answer 1
they run out of hydrogen to burn, decreasing the amount of energy they emit. Thus, younger stars can appear bluer while older ones appear more red, and in this way, a star's color can tell us something about that star's age.

Related Questions

Which of the following examples best illustrates an effect of pollution on an ecosystem?
Choose 1 answer:
Choose 1 answer:

(Choice A)
A
Cutting down a forest for lumber removes available habitat for local animals, forcing them to move or compete for remaining resources.

(Choice B)
B
The number of wolves in an area declines due to urbanization and hunting, allowing elk and deer populations to grow rapidly.

(Choice C)
C
Nitrogen and phosphorus runoff from agricultural fields creates harmful algal blooms and dead zones in the ocean.

Answers

Choice C: Nitrogen and phosphorus runoff from agricultural fields creates harmful algal blooms and dead zones in the ocean.

How many moles of NH3 can be made from 0.93 moles N2?
0.62 mol NH3
1.86 mol NH3
0.93 mol NH3
0.47 mol NH3

Answers

I think the answer is D


Three categories of factors that cause illness or injury are shown here. Match each example on the right to its correct match on the
left.
A baby is born with an abnormal number of chromosomes.
Angela was badly injured in a car accident after her air bag
exploded.
Alex forgot to get a flu shot and missed two weeks of school
with the flu. Answer choices pathogenic agents, genes , environmental factors

Answers

Answer:

Alex forgot to get a flu shot and missed two weeks of school

is the compound Fed3 ionic or covalent

Answers

The complete question is: Is the compound [tex]FeCl_{3}[/tex] ionic or covalent ?

Answer: Compound  [tex]FeCl_{3}[/tex] is an ionic in nature.

Explanation:

When a metal atom combines with a non-metal atom then transfer of electrons take place from metal towards the non-metal. As a result, an ionic bond is formed between the atom and compound formed is called an ionic compound.

For example, [tex]FeCl_{3}[/tex] compound contains Fe atom which is a metal and Cl atom which is a non-metal. Hence, electrons will be transferred from Fe atom to the Cl atom forming an ionic bond.

Hence, [tex]FeCl_{3}[/tex] is an ionic compound.

Thus, we can conclude that [tex]FeCl_{3}[/tex] is an ionic compound.

Convert particles to moles: 8.3 x 10^20 atoms Cu

Answers

Answer:

[tex]\boxed {\boxed {\sf 0.0014 \ mol \ Cu}}[/tex]

Explanation:

We are asked to convert particles to moles.

1. Avogadro's Number

1 mole of any substance contains the same number of particles (atoms, molecules, formula units). This is Avogadro's Number or 6.022*10²³.

In this problem, the particles are atoms of copper. So, 1 mole of copper contains 6.022*10²³ atoms of copper

2. Convert Atoms to Moles

Use Avogadro's Number to make a ratio.

[tex]\frac{ 1 \ mol \ Cu}{ 6.022*10^{23} \ atoms \ Cu}[/tex]

We are trying to convert 8.3*10²⁰ atoms of copper to moles, so we multiply that value by the ratio.

[tex]8.3*10^{20} \ atoms \ Cu*\frac{ 1 \ mol \ Cu}{ 6.022*10^{23} \ atoms \ Cu}[/tex]

The units of "atoms Cu" will cancel.

[tex]8.3*10^{20}\frac{ 1 \ mol \ Cu}{ 6.022*10^{23} }[/tex]

Condense the expression into 1 fraction.

[tex]\frac{8.3 *10^{20}}{ 6.022*10^{23} } \ mol \ Cu[/tex]

[tex]0.001378279641 \ mol \ Cu[/tex]

3. Round

The original measurement of atoms has 2 significant figures, so our answer must have the same. For the number we calculated that is the ten-thousandths place.

0.001378279641

The 7 in the hundredth thousandth place tells us to round the 3 up to a 4.

[tex]0.0014 \ mol \ Cu[/tex]

8.3*10²⁰ atoms of copper are equal to 0.0014 moles of copper.

Which molecule is a stereoisomer of trans-2-pentene?

Answers

Answer:

cis-2-pentene

Explanation : The stereoisomers are the compound which differs only in the spatial arrangement of the atoms across the stereogenic centers.

There are mainly two forms of stereoisomers cis and trans. Cis-isomers are those where the two bulky or functional groups are arranged on the same side across the stereogenic center; whereas, in trans-isomers the two bulky groups or functional groups are arranged in the opposite sides of stereogenic center.

When an object is pushed by a force and moves in the direction of the force, work is done on the object. The amount of work equals the force times the distance (W = Fd). A small particle is pushed by a force of 2.6 × 10-4 newtons over a distance of 3.7 × 10-3 meters. How much work was done on the particle? Express the answer to the correct number of significant figures and in proper scientific notation. The force did × 10 newton-meters of work on the particle.

Answers

Explanation:

[tex]workdone = force \times distance \\ W = (2.6 \times {10}^{ - 4} ) \times (3.7 \times {10}^{ - 3} ) \\ W = 9.62 \times {10}^{ - 7} \: joules[/tex]

The formula W = Fd, where W is the amount of work done, F is the force, and d is the distance, is used to determine how much work is done on a particle when it is pushed by a force. The force and distance in this issue are 2.6 10-4 newtons and 3.7 10-3 metres, respectively.

What is the way to calculate the work done ?

We add the force and distance together to determine the work done: 9.62 10-7 newton-meters are equal to W = 2.6 10-4 newtons x 3.7 10-3 metres. The response must be presented using the appropriate scientific notation and significant numbers.

The solution should include three significant figures, just like the numbers in the problem, which have three. Therefore, 9.62 10-7 newton-meters is the correct answer.

This response uses appropriate scientific language.notation because the exponent is a negative power of 10 and the coefficient ranges from 1 to 10. In conclusion, the particle underwent work from the force of 9.62 10-7 newton-meters. This response uses the appropriate scientific notation and the correct number of significant digits.

Learn more about  force at:

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help pls it's about cells

Answers

This is it what u wanted



Yep





How





Yep

What is energy? Give at least two examples of how you use energy in your everyday life.

Answers

Answer:

To walk or run, and to wake up.

The capability or ability to do work is called energy

Find A in degrees. Round to the
nearest tenth.
С
a = 7
b
b = 4
a
C = 8
B
A
С
A = [?]

Answers

Answer:

61 degrees

Explanation:

Which physical property causes cork to float on top of water?

Answers

I believe the answer is density l. Density is the physical property that allows a cork to float on water.
Density we learned about this in elementary in 3rd grade

pls I need this fast.
Write and overall equation for the acid-base reaction that would be required to produce each of the following salt : NaCI

Answers

Explanation:

HCl(aq)+ NaOH(aq)→NaCl(aq)+H2O(l) ..

how is melting similar to freezing

Answers

Answer:

no similarities but if that's so it's temperature

How many hydrogens are in 4H207?

Answers

4 I think
Hope that helped
8
It’s 8 because you mulitiply 4x2 so if you had to do oxide(oxygen) it would be 4x7 cuss you multiply the number added before H2O7 and the small numbers already there (deside it) is multiplied
Hope this helps you

Cat added a sample of sodium hydroxide to water and
determined the pH to be 12. What is the pOH of the solution?
pOH =

Answers

Answer: 2

Bc when you subtract 12 from 14 you get 2

A student increases the temperature of a 355 cm3 balloon from 325K to 353K. What
will the new volume of the balloon be?
Charles's Law
V 부
273 cm
3
327 cm
3
353 cm 3
386 cm
3

Answers

Answer:

385.6cm³

Explanation:

Using Charles law equation as follows;

V1/T1 = V2/T2

Where;

V1 = initial volume (cm³)

V2 = final volume (cm³)

T1 = initial temperature (K)

T2 = final temperature (K)

According to the information provided in this question;

V1 = 355cm³

V2 = ?

T1 = 325K

T2 = 353K

Using V1/T1 = V2/T2

355/325 = V2/353

1.092/1 = V2/353

Cross multiply

1.092 × 353 = V2

V2 = 385.6cm³

A 2.50 L balloon is filled with water at 2.27 atm. If the balloon is squeezed into a 0.80 L beaker and does NOT burst, what is the pressure of water in the balloon?

Answers

Answer:

[tex]P_2=7.09atm[/tex]

Explanation:

Hello!

In this case, given the change in volume and pressure of the gas, it is possible for us to recall the Boyle's law as way to understand the inversely proportional relationship between pressure and volume:

[tex]P_1V_1=P_2V_2[/tex]

Thus, when solving for the final pressure, P2, given the initial pressure and volume and the final volume, we obtain:

[tex]P_2=\frac{P_1V_1}{V_2}\\\\P_2=\frac{2.27atm*2.50L}{0.80L}\\\\P_2=7.09atm[/tex]

Best regards!

Answer:

7.1 atm

Using Boyle’s law, P1 V1=P2 V2.

What is the molarity of a 0.4 liter solution containing 1.6 moles of NaCl?

Answers

Answer:

4 M

Explanation:

Molarity refers to the molar concentration of a substance (solution). It can be calculated by using the formula below:

Molarity (M) = number of moles (n) ÷ volume (V)

According to the information provided in this question;

V = 0.4 liter

n = 1.6 moles

Molarity = n/V

Molarity = 1.6/0.4

Molarity = 4 M

electronic configurations and charges of the ions
in lithium fluoride?​

Answers

Answer:

Explanation:

The electronic configuration of a lithium atom is 2.1 and that of a fluorine atom is 2.7

an atom of lithium donates an electron to an atom of fluorine to form an ionic compound. The transfer of the electron gives the lithium ion a net charge of +1, and the fluorine ion a net charge of -1.

I’m kinda stuck with this part of the paper

Answers

Answer:

oK so pay pattention to the fractions

Explanation:

Why were scientists unsure about the last common ancestor between apes and humans?

Answers

Answer:

Scientists were unsure about the last common ancestor between apes and humans because fossils are so scarce, researchers do not know what the last common ancestors of living apes and humans looked like or where they originated.

Explanation:

The pH of a solution is 2.55. What is the [H3O+]?

Answers

Answer:

[H₃O⁺] ≈ 0.00282 M

General Formulas and Concepts:

Acid/Base Equilibria

Bronsted Acid/Bronsted Base

pH Formula: pH = -log[H₃O⁺]

[H₃O⁺] Formula: [tex]\displaystyle [H_3O^+] = 10^{-pH}[/tex]

Explanation:

Step 1: Define

pH = 2.55 (Acidic)

Step 2: Solve

Substitute in pH [Molar Concentration Formula]:                                              [tex]\displaystyle [H_3O^+] = 10^{-2.55}[/tex]Evaluate exponent:                                                                                          [tex]\displaystyle [H_3O^+] = 0.002818[/tex]

Step 3: Check

Follow sig fig rules and round. We are given 3 sig figs.

0.002818 M ≈ 0.00282 M

PLEASE HELPP MEEE ASAPPPPP

Answers

Answer:

2. Solute

3. Suspension

4. Colloid

5. Compound

Explanation:

Which of the following is the weakest type of intermolecular
force?
o Hydrogen bonding
o Induced dipole
London dispersion
o Dipole-dipole

Answers

Answer:

London Dispersion

for the oxidation of iron to form iron(iii)oxide
4Fe(s)+3O2(g)=2Fe2O3(s) deltaS^o=-549.73J×K^-1 at 298K
the enthalpy of formation of Fe2O3(s) is -824.2 kj×mol^-1. what is the standard change in gibbs free energy for this reaction at 298K? Delta G^o=delta H^o-T delta S^o

Answers

Answer:

only god knows the answer

The Gibbs free energy is given by the change in enthalpy, temperature, and change in entropy. The standard change in Gibbs free energy for oxidation of iron is –1484.6 kJ.

What is Gibbs free energy?

Gibbs free energy is the energy present in a thermodynamic system that is used by the reactant to form a product. It is given as,

Δ G° = Δ H° -T ΔS°

The oxidation reaction of iron is given as,

4Fe(s) + 3O₂(g) → 2Fe₂O₃(s)

Given,

ΔS° = –549.73 J∙K⁻¹

T = 298 K

Δ H° = –824.2 kJ∙mol⁻¹

Substituting values above the Gibbs free energy is calculated as:

Δ G° = Δ H° -T ΔS°

= –824.2 kJ∙mol⁻¹ -  298 K ( –549.73 J∙K⁻¹)

= -1484580.46 J

The units of joules are converted into kilojoules and the standard change in Gibbs free energy will be –1484.6 kJ.

Therefore, –1484.6 kJ is the Gibbs free energy.

Learn more about Gibbs free energy here:

https://brainly.com/question/13318988

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The Sun’s Influence on Atmosphere and Oceans
Note-taking Guide

Directions: Complete the note-taking guide using the words in the word bank below. To enter your answers, click on the blanks and type.


weather hurricanes poles convection currents warming salt
global conveyor belt surface currents dense equator
Loop Current salinity climate heat cooling wind


The Sun is the main energy source on Earth. Approximately
50%
of the
solar energy hitting Earth is absorbed by land and oceans.


This absorbed energy changes into


which can be transferred to


the atmosphere. As the air in the atmosphere then gets heated, it becomes


less


and rises.


Cool, dense air from other places flows in to replace this warm air, which we


feel as


.


This cool air eventually heats and starts to rise again. This continual process
of air closest to Earth’s surface warming, rising, cooling, and then sinking


creates


in the atmosphere.


Atmospheric winds that blow over the ocean surface create




that carry water around the globe.


Unequal heating of the oceans and differences in


also


create currents.


The Sun warms water at the


more than it does at the
high latitude Polar regions.




At the


, some water freezes. The water that doesn’t freeze


contains more


, making it denser.


As this cold, dense water sinks, the warm water from the equator moves
toward the poles to replace it.
This constant movement creates a deep ocean current called the




.


The global conveyor belt transfers heat from one part of the world to the


other, thus affecting the


and


in all parts


of the world.


Surface and deep ocean currents continually transfer warm and cold waters
around the globe.
As these waters warm or cool the air above it, winds blow the air over land,




it up or


it down.


The


in the Gulf of Mexico is an ocean current


that creates a warm layer of water in the gulf. This results in the growth of


several


that affect the Gulf Coast.

Answers

Answer:

bestie this is like 6th grade stuff

Explanation:

A surfact that DOES NOT allow water to pass through.​

Answers

Answer:

impermeable

Explanation:

Answer:

aquifer?

Explanation:

At the same conditions of temperature and pressure, 5.0 dm^3 of a gas of molecular formula C_2 H_2, has a mass of 15 g, while 1.0 dm^3 of gas D has a mass of 1.4 g. What is the molar mass of gas D?

Underscore means subscript but I can't get the equation thingy to work. So it's meant to be C(subscript 2)H(subscript 2)

Answers

Answer:

12 g/mol

Explanation:

From Avogadro's law;

V1/n1 = V2/n2

V1 =  5.0 dm^3

n1 = 15 g/26 g/mol = 0.6 moles

V2 = 1.0 dm^3

n2 = ?

V1n2 = V2n1

n2 = V2n1/V1

n2 = 1 * 0.6/5

n2 = 0.12 moles

Molar mass= mass of gas D/number of moles of gas D

Molar mass= 1.4 g/0.12 moles

Molar mass= 12 g/mol

Li2O + MgCl2 → 2 LiCl + MgO
What type of reaction is going on in this equation.

Answers

Answer:

water

Explanation:

If the student added larger drops to the pan, the
what?of the waves would increase.

Answers

Answer:

this makes no sense you arent gonna get help

Explanation:

Answer:

Amplitude

Explanation:

Im taking this test rn lol

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