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Answer:

Distance also affects the apparent brightness of an object. A distant, but very energetic star can appear dimmer to us than a lower-energy, but closer one. ... Each of their effective temperatures results in a different brightness for the object. The quasar, however, is very far away, and so appears dim.

Explanation:

AnswerB:

Explanation:

Heat can travel from one place to another in different ways. The different methods of heat transfer are conduction, convection and radiation. Here heat transfers from the glass to the ice through conduction.

The process of transmission of energy from one particle of the medium to another with the particles being in direct contact with each other is defined as the conduction. It is also known as the thermal conduction or heat conduction.

In conduction an area of higher kinetic energy transfers thermal energy towards the lower kinetic energy area. Here a transfer of heat energy occurs from tea molecules to the ice cube. Due to the transfer of heat melting of ice occurs.

As the ice melts, the tea starts cooling while heating the ice cube. So the ice cools down the tea. The tea will be melted by the ice here.

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Answer:

A

Explanation:

This is because in the graph shown line A has a quite greater impact of refraction than line B .

Hence, we can conclude that line A has the greater reaction at a faster rate.

Answer:

True

Explanation:

this is part of the cell theory

Answer: Sodium chloride is an ionic solid, and when it dissolves in water, its individual sodium and chloride ions are dissociated from one another. Sugar molecules, on the other hand, maintain the bonds between their constituent atoms when dissolved, and thus remain as whole molecules in the solution.

Explanation: Here's why: Salt is about 25% more dense than sugar. Therefore a teaspoon of salt weighs more than a teaspoon of sugar by almost 25%. Your dissolving test would not be accurate because you would be starting out with a larger mass of salt than sugar.

Answer:

Sulfur tetra fluoride

Explanation:

Answer:

I will draw how the city looks like

Answer:

57 mL

Explanation:

To make things clear, when 769 mL of ethanol were mixed with 507 mL of water, the resulting volume was not (769+507) 1276 mL, but a lower value. This is because of the interactions between liquid molecules.

First we calculate how many grams of ethanol are there in 769 mL, using the given density:

Then we convert 606.97 g of ethanol into moles, using its molar mass:

Now we calculate the actual volume of the solution, using the definition of molarity:

Finally we convert 1.219 L to mL, and calculate the difference in volume:

Answer:

2 electron shells

hope it helps

and your day will be full of happiness

Answer:

Alkali metals

Explanation:

The lowest number of valence electrons is found in the alkali metals (group 1), which have only one valence electron per atom.

Answer:

Alkali metals:) im 100% sure because i just got done learning everything in the periodic table:)

Explanation:

Answer: 3

Explanation: 5 times a number would be 5x, then increase that by 4 is 5x+4.  The problem then says 5x + 4 ≥ 19.  If we solve for x then we get x ≥ 3 so x has to be greater than or equal to 3, so the smallest number it could be is 3.  You can even try any number smaller than 3 and see it doesn't work.  even something like 2.9

Answer:

As the axial tilt increases, then the seasonal contrast increases so that winters are colder and summers are warmer in both hemispheres. The northern hemisphere is tipped away from the Sun, producing short days and a low sun angle. What kind of effect does the earth's tilt and subsequent seasons have on our length of daylight (defined as sunrise to sunset). Over the equator, the answer is not much.

Answer:

[tex]2Al(s) + 3NiSO4 --> Al2(SO4)3 + 3Ni[/tex]

Explanation:

This reaction type is a single replacement. The format of a single replacement is:

[tex]A+BC --> B+AC[/tex]

A= Al

B= Ni

C= SO

The coefficient 3 for Ni would become a subscript for  AC. After you plug those into the reaction you need to count how many of each are on the left side and try to get the same number on the right side. Both sides must be equal to have a balanced equation.

Answer:

A. 0.48mol O2

Explanation:

The balanced equation is given as follows:

2CH3OH + 3O2 → 2CO2 + 4H2O

This shows that 2moles of CH3OH is required to react with 3 moles of O2

If 0.32 moles of CH3OH are reacted, then;

0.32 × 3/2 moles of O2 is required

= 0.96/2

= 0.48mol of O2

D is the answer -3                            m              

Answer:

filtration is the answer

Explanation:

Answer:

The mass of water produced is 4.29 g.

Explanation:

Given;

reacting mass of ethane, C₂H₆ = 2.5 g

reacting mass of oxygen, O₂ = 5.0 g

The balanced combustion reaction is given as follows;

2C₂H₆   +   7O₂ ---------------->  4CO₂    +   6H₂O

Based on the balanced equation above;

                                     requires

7.0 moles of oxygen ----------------------->   2.0 moles of ethane

                                   requires

5.0 g of oxygen      -------------------------->  x gram of ethane

x = (2 x 5) / 7

x = 1.43 g

Ethane is in excess of 1.07g (2.5 g - 1.43g)

Now, determine the mass of water produced by 1.43 g of ethane;

                                   requires

2.0 moles of ethane ----------------------->   6.0 moles of water

                                   requires

1.43 g of ethane      -------------------------->  y  gram of water

y = (6 x 1.43) / 2

y = 4.29 g

Therefore, the mass of water produced is 4.29 g.

The formula of a compound is written based on the valency of each bonded atoms. The formulas  Mg₂(SO₄)₃, Rb₃As are incorrect. Such compounds does not exist.

The formula of a chemical compound is written based on the number of atoms participated in bonding.   Magnesium is second group element having two valence electrons.

Magnesium thus donates its two electrons into the bonding atom or group. The sulphate group SO₄ have a valency of 2 it gains two electrons from Mg when bonded.

Thus the formula of magnesium sulphate being MgSO₄ and not Mg₂(SO₄)₃. Similarly Rb is a second group metal having two valence electrons. Its valency being two. As is a halogen with valency one. Thus they cannot form a compound like Rb₃As.

Hence, option a and b are incorrect formulas.

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Answer:

4.26m

Explanation:

Molality , m, is an unit of concentration in chemistry defined as the ratio between moles of solute (In this case, NaCl) and kg of solvent (In this case, water).

To solve the question we need to find the moles of NaCl and the mass of water in kg:

Moles NaCl -Molar mass: 58.44g/mol-:

11.7g * (1mol / 58.44g) = 0.200 moles

Mass of Water in kg:

47g * (1kg / 1000g) = 0.047kg

Molality is:

0.200 moles / 0.047kg =

4.26m

Answer: 300 g

Explanation: I guessed and got it right

420 liter of volume is occupied by 300 grams of methane gas at standard temperature and pressure (STP).

Ideal gas equation of methane gas at STP (standard temperature pressure) can be written as:

PV = nRT, where

P = pressure = 1 atm

V = volume = 420 L (given)

R = universal gas constant = 0.082 L.atm / k.mole

T = absolute temperature = 273 K

n = no. of moles to find?

Putting all these values in the above equation and calculated for the n:

n = (1 × 420) / (0.082 × 273) = 18.76 moles

Now we calculate mass of methane by the definition of moles as:

n = W/M, where

M = molar mass of methane = 16 g/mole

W = to find?

W = 18.76 × 16 = 300.2 grams or 300grams.

Hence, option (c) is correct i.e. 300 grams of methane occupy 420 L volume.

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Answer:

algee

Explanation:

Answer:

if you are a teen then its pretty normal as during the age of adolescent sweat gland become active and pimples take place on you face , no need to worry at this your face will become beautiful again .

but if you are above 25 then it is a time to worry , you should consult a doctor or you can use alovera jel or any other home remedies. :)

Answer:

14

Explanation:

Mass number is just the value of the protons and neutrons added, in this case its 14

Answer:

2

Explanation:

Answer:

1. Sperm - The male reproductive cell

2. Fertilization - The union of the male gamete (sperm cell) and the female gamete (egg cell)

3. Conception - The fertilization of a female egg cell with a male sperm cell

4. Testes, Testicles - Male gonads

5. Ovary, Ovaries - Female gonads

6. Gonad - Gamete-producing organ in animals

7. Eggs - Female reproductive cells

8. Hormone - a body chemical that controls growth and activity

Explanation:

Hope this helped!