EMERGENCY: I WILL FAIL: PLS HELP WILL MARK BRAINLIEST JUST PLS HELP

Answer:

Dark matter also called baronic matter is the matter that makes up 27% of the universe.

In 1933 it was determined as that mass that cannot be seen, that is, the non-visible mass of outer space.

Dark matter also plays a central role in the formation of structures and the evolution of galaxies and has measurable effects on the anisotropy of cosmic microwave background radiation. The composition of this matter is unknown today.

The dark matter component has considerably more mass than the "visible" component of the Universe.

Explanation:

There are certain researchers who say that the appearance of dark matter was before the appearance of the big bang.

A relevant fact of this matter is that dark matter exerts gravity, and that gravity affects the movements of objects.

Despite the fact that nothing is known about its origin, astronomers have amply demonstrated that dark matter plays a determining role in the formation of galaxies and galactic clusters, which could not maintain their cohesion without its existence, but many doubt that it is the remainder / remnant or product of a big bang.

"Typical nonmetals have a dull, coloured or colourless appearance; are brittle when solid; are poor conductors of heat and electricity; and have acidic oxides." - Wikipedia

Answer:

The molecules in a solid are stuck in a specific structure or arrangement of atoms. The atoms still vibrate and the electrons fly around in their orbitals, but the entire atom will not change its position.

Answer:

2.078x10^24

Explanation:

No. of atoms of chlorine = 3.45 x 6.022x 10 ^23 x 1

= 2.078x10^24

( to find no. of atoms of, heres the formula i was taught No. of atoms = no. of moles x Avogadros constant x no. of atoms in the formula of compound)

Answer:

0.03

Explanation:

22.8 g Ba(OH)2 (1 mol Ba (OH)2/ 171.34 g) = 0.133 mol Ba (OH)2

77.2 g H2O (1 mol H2O/18 g) = 4.29 mol H2O

X= molar fraction= mol Ba(OH)2/ mol total

X= 0.133/ (0.133+4.29) = 0.03

0.03 is the mole fraction of [tex]Ba(OH)_2[/tex] in an aqueous solution that contains 22.8% [tex]Ba(OH)_2[/tex] by mass.

The ratio of the number of moles of one component of a solution or other mixture to the total number of moles representing all of the components.

Moles of [tex]Ba(OH)_2[/tex]

Moles = [tex]\frac{mass}{molar \;mass}[/tex]

Moles = [tex]\frac{22.8 g Ba(OH)_2}{171.34 g}[/tex]

= 0.133 mol [tex]Ba (OH)_2[/tex]

Moles of [tex]H_2O[/tex]

[tex]Moles = \frac{mass}{molar \;mass}[/tex]

[tex]Moles = \frac{77.2 g H_2O}{18 g}[/tex]

= 4.29 mol [tex]H_2O[/tex]

The mole fraction of [tex]Ba(OH)_2[/tex]

[tex]\frac{mol Ba(OH)_2}{total \;mol}[/tex]

= 0.03

0.03 is the mole fraction of [tex]Ba(OH)_2[/tex] in an aqueous solution that contains 22.8% [tex]Ba(OH)_2[/tex] by mass.

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Answer:it is D

Explanation: it is only one that makes sense

C. The concentrations of liquid water and water vapor are stable. it describes the fact that liquid water and water vapor are at equilibrium.

Hence, option (c) is correct. The concentration of liquid water and water vapor will become stable.

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Hey there!

P₄ + Cl₂ → PCl₃

First, let's balance Cl.

There are 2 on the left, and 3 on the right.

To balance this, let's put a coefficient of 3 in front of Cl₂ and a coefficient of 2 in front of PCl₃.

P₄ + 3Cl₂ → 2PCl₃

Now we have 6 on the left and 6 on the right.

Next, let's balance P.

There are 4 on the left and 2 on the right.

Let's change the coefficient in front of PCl₃ from 2 to 4.

P₄ + 3Cl₂ → 4PCl₃

There are now 4 P on each side.

However, now Cl is unbalanced, with 6 on the left and 12 on the right.

We can change the coefficient in front of Cl₂ from 3 to 6.

P₄ + 6Cl₂ → 4PCl₃

So now, we have 4 P on each side and 12 C on each side.

This is our final balanced equation.

Hope this helps!

Answer:

1:1

Explanation:

Took test

Answer:

Greenhouse gases such as carbon dioxide and water vapor make an atmosphere around the earth and make less heat escape

Explanation:

Answer:

The answer is NaOH

Explanation:

Strong bases are characterized by the fact that they dissociate completely in an aqueous solution. In this case, sodium hydroxide, NaOH, is classified as a strong base because it dissociates completely in an aqueous solution to form sodium cations, Na+, and hydroxide anions, OH−. Also, it is strong because it totally breaks in its ion. And the base which breaks totally in its atom called the strong base and which doesn't it that is a weak base.

Answer:

NaOH

Explanation:

Got it right in the test. Please mark as brainliest

Answer:

unbalanced

Explanation:

Cl and H have an extra atom

- Hope that helps! Please let me know if you need further explanation.

Answer:

D working alone

Explanation:

Working alone is the only option that could potentially be a safety hazard; if you have no one watching your back, errors could occur, like dropping glass or burning your hand, and no one is around to help you.

Choices A, B, and C are not correct because those are all good safety standards.

Answer:

Gamma Rays.

Explanation:

Gamma-ray photons have the highest energy in the EMR spectrum and their waves have the shortest wavelength.

Answer:

55×10^-26 J

Explanation:

We can calculate the energy of the wave from

E= hc/λ

Where

h= Planks constant = 6.6×10^-34 Is

c= speed of light = 3×10^8 ms-1

λ= wavelength of the wave = 0.36 metres

Recall that cell phone use radio waves which belong to the electromagnetic spectrum hence it must possess the speed of light.

E= 6.6×10^-34 × 3×10^8/ 0.36

E= 55×10^-26 J

Hence the energy possessed by 0.36 meters wavelength radio waves is 55×10^-26 J

Answer:

C

Explanation:

The answer is always C

Answer:C. Concave mirror

Explanation:

When the surface of a mirror curves inward, like the inside of a bowl, it is called c. Concave mirror.

Answer:

0 °C and 1 Atm,

Explanation:

Standard Temperature and Pressure. Standard temperature is equal to 0 °C, which is 273.15 K.

Standard Pressure is 1 Atm, 101.3kPa or 760 mmHg or torr

Answer:

el nino: the boy

la nina: the girl

Explanation:

Answer:

el nino is dinosour la nino is fishcat

Explanation:

The biggest disadvantage of using nuclear power to produce electricity is the nuclear waste must be safely stored for many years.

Nuclear power is the use of nuclear reactions to produce electricity. Nuclear power can be obtained from:

Nuclear reactions produces high amount of energy and many waste materials which are non degradable and will stay in the environment for the long time.

Hence, nuclear waste must be safely stored for many years.

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Answer:

The planets themselves are composed of several trillions or quadrillions or more atoms. As far as hard science is concerned, it would be really hard to picture them as electrons. Conclusion: It can be said with a great accuracy that our planets are NOT huge electrons.

Rutherford's experiments showed that the mass of atoms was mostly concentrated in a very small region, with charge equal to the atomic number- the nucleus. He absolutely did not show, nor is it true, that electrons orbit the nucleus as if they were planets. That was a guess people made in trying to figure out how to picture the atom.

(Hope this helps) Sky

Answer:

B the density stays the same

Answer:

Explanation:

Soap breaks up the oil into smaller drops, which can mix with the water. It works because soap is made up of molecules with two very different ends. One end of soap molecules love water - they are hydrophilic. The other end of soap molecues hate water - they are hydrophobic.

Answer:

C. Its polar end mixes with the water so it can be washed away.

Explanation:

Just took test

Answer:

all of them except number 2

Explanation:

Answer:

1,3,4,5  the other perosn is correct

Explanation: That what my quiz said

Answer:

Heat energy (Q) = 1.9925 KJ = 2 KJ (Approx)

Explanation:

Given:

Mass of copper (M) = 45 gram

Change in temperature (ΔT) = 71°C - 12°C = 59°C

Specific heat (c) =0.75 j /g*c

Find:

Heat energy (Q) = ?

Computation:

Heat energy (Q) = Mass(M) × Change in temperature (ΔT) × Specific heat (c)

Heat energy (Q) = 45 gram × 59°C × 0.75 j /g*c

Heat energy (Q) = 1991.25 J

Heat energy (Q) = 1.9925 KJ = 2 KJ (Approx)

Answer:

 24He

Explanation:

When a nuclide is bombarded with alpha particles, we notice an increase in its mass and charge since an alpha particle has a mass of four and a charge of +2. recall that nuclear equations must be balanced. That is, the masses and charges on the left hand six and the right hand side of the nuclear reaction equation must be exactly the same.

Looking at the nuclear reaction at hand, the total mass on the left hand side has to be 246 while the total charge on the left hand side of the equation will be 98. Coming over to the right hand side, the total masses are also found to be the same as a neutron with no charge and a mass of 1 is produced. Hence the nuclear reaction equation is balanced when an alpha particle (helium nucleus) is substituted for X in the equation.

Answer:

24HE

I took the test!

Answer:

b

Explanation:

Electromagnetic waves are waves that have no medium to travel whereas mechanical waves need a medium for its transmission.

Answer:

answer: A. all of the living organisms in a specific place at a specific time

Explanation:

Answer:

Should be A

Explanation:

Answer:

b

Explanation:

it is right

Answer:

0.479 M or mol/L

Explanation:

So Molarity is moles/litres of solution...often written as M=mol/L

So here we are given grams of BaCl2 which we have to convert to moles. To convert to moles of BaCl2 we have to divide 63.2 g BaCl2 by molar mass of BaCl2 which is 208.23 g/mol so you get 63.2/208.23 = 0.3035 moles of BaCl2

Second step is converting the 634mL to litres by simply dividing by 1000 because we know 1 litre has 1000ml so 634/1000 = 0.634L

Now we just plug these guys in our molarity formula M=mol/L

M= 0.3035/0.634 = 0.479 M or mol/L

Answer:

Interestingly enough, I'm not getting

0.0341% w/v

either. Here's why.

Start by calculating the percent composition of chlorine,

Cl

, in calcium chloride, This will help you calculate the mass of chloride anions,

Cl

−

, present in your sample.

To do that, use the molar mass of calcium chloride, the molar mass of elemental chlorine, and the fact that

1

mole of calcium chloride contains

2

moles of chlorine atoms.

2

×

35.453

g mol

−

1

110.98

g mol

−

1

⋅

100

%

=

63.89% Cl

This means that for every

100 g

of calcium chloride, you get

63.89 g

of chlorine.

As you know, the mass of an ion is approximately equal to the mass of the neutral atom, so you can say that for every

100 g

of calcium chloride, you get

63.89 g

of chloride anions,

Cl

−

.

This implies that your sample contains

0.543

g CaCl

2

⋅

63.89 g Cl

−

100

g CaCl

2

=

0.3469 g Cl

−

Now, in order to find the mass by volume percent concentration of chloride anions in the resulting solution, you must determine the mass of chloride anions present in

100 mL

of this solution.

Since you know that

500 mL

of solution contain

0.3469 g

of chloride anions, you can say that

100 mL

of solution will contain

100

mL solution

⋅

0.3469 g Cl

−

500

mL solution

=

0.06938 g Cl

−

Therefore, you can say that the mass by volume percent concentration of chloride anions will be

% m/v = 0.069% Cl

−

−−−−−−−−−−−−−−−−−−−

I'll leave the answer rounded to two sig figs, but keep in mind that you have one significant figure for the volume of the solution.

.

Explanation: