help!
The speed of light in vacuum is 300,000,000 m/s and the speed of light in water is 225,000,000 m/s. What is the refractive index?
A. 1.33
B. 1.5
C. 1
D. 2.33

Answer:

It decreases first and then remains constant.

Explanation:

Answer:

It decreases first and then remains constant.

Explanation:

Answer:

Au = Element

NaCl = Compound

Salad = Heterogeneous

NaCl & Water = Homogeneous

Answer:

The force must be in the same direction as the object’s motion

Explanation:

Force is a physical quantity.

It is defined as the force applied to a body to move it in the direction of the force applied.

  Force  = mass x acceleration.

So, option is C is the correct choice.

Answer:

Honey

Explanation:

i know why but at the same time i don't. i know that water, tea, and milk are very fluid however honey is sticky and isn't AS FLUID as the others.

Therefore, honey as the highest viscosity.

Answer:

1802

Explanation:

 Humphry Davy invented the first electric light

Answer:

1806

Explanation:

The very first light bulb was not invented by Thomas Edison, but by British inventor Humphry Davy in 1806. His devices created an arc of electricity between electrodes, creating a very bright light. While far too dangerous to use at home, they were used in public spaces and commercially.

Hope this helps! :)

PLEASE MARK ME AS BRAINLIEST I REALLY WANT TO LEVEL UP

Answer:

b

Explanation:

Answer:

A-20 B-40 C-Ca D-10 E-9 F-F

Explanation:

Crystallisation

(used to separate solids from a solution)

Hope this helps!

Answer:

a reaction in which one element is substituted for another element in a compound

Explanation:

Answer:

6 liquids

Explanation:

because yea

Graduated cylinder is used for accuracy

Answer:

A.The two ends are like poles

Explanation:

Magnets are composed of a north pole and a south pole. If two like poles of a magnetic are placed near each other, the two ends seem to push apart.

The reason for this is that, when like poles of two magnets are made to face each other, the lines of forces are in opposite directions, hence the magnets repel.

If unlike poles of two bar magnets are made to face each other, the magnetic lines of force are now in the same direction therefore the unlike poles attract each other.

Answer:

D

Explanation:

I am sorry if wrong

Answer:

C

Explanation:

I tested the other answer and it was wrong, when I put C I got 100... Your welcome!

Density, Melting point, Boiling point and Hardness  are examples of physical properties.

A physical property refers to that property which is measurable and whose value indicates a state of a physical system. Examples of physical properties are Density, Melting point, Boiling point and Hardness so we can conclude that Density, Melting point, Boiling point and Hardness  are examples of physical properties.

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The heat released : -110560.632 J

Heat can be calculated using the formula:  

Q = mc∆T  

Q = heat, J  

m = mass, g  

c = specific heat, joules / g ° C  

∆T = temperature difference, ° C / K  

m =465 g

c water = 4.186 J/gram °C

∆T = temperature difference = 18.2 - 75 = - 56.8 °C

Then the heat :

[tex]\tt Q=m.c.\Delta T\\\\Q=465\times 4.186\times -56.8\\\\Q=\boxed{\bold{-110560.632~J}}\rightarrow -=exothermic[/tex]

From the calculations, the specific heat capacity of diamond is 42.36  J/Kg/°C.

The specific heat capacity is the heat absorbed or emitted when 1Kg of a susbtance is heated such that its temperature is increased by 1 K.

Now;

Mass of water = 26.05 g or 0.026 Kg

Mass of diamond = 2.05 g or 0.00205 Kg

specific heat capacity of water = 4200 J/Kg/°C

specific heat capacity of diamond = ?

Initial temperature of water =  27.20°C

Initial temperature of diamond =74.21 °c

Final temperature of the diamond and water = 27.65 °c

Heat lost by diamond = heat gained by water

mcdT = mcdT

0.00205 Kg * c * ( 74.21 °c - 27.65 °c ) = 0.026 Kg * 4200 J/Kg/°C * (27.65 °c - 27.20°C)

0.116c = 4.914

c = 4.914/0.116

c = 42.36  J/Kg/°C

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Answer:

build better enclosures to decrease overgrazing by livestock.

Explanation:

Answer:

The answer is number 1

Explanation:

this is because cease means to stop,and recession also means to squeeze

Answer:

Take the weighted average of the individual isotopes.

Explanation:

63

C

u

has

69.2

%

abundance.

65

C

u

has

30.8

%

abundance.

So, the weighted average is

62.93

×

69.2

%

+

64.93

×

30.8

%

=

63.55

amu

.

If we look at the Periodic Table, copper metal (a mixture of isotopes but

63

C

u

and

65

C

u

predominate) has an approximate atomic mass of

63.55

g

⋅

m

o

l

−

1

, so we know we are right.

Answer:

A) acetic acid

Explanation:

Acetic acid most likely has the strongest intermolecular forces. Hence, option A is correct.

The boiling point of a substance is the point at which the vapour pressure of a liquid is equal to the surrounding pressure and water is 313k for absolute temperature and 212°F for Fahrenheit.

The intermolecular force of attraction depends on the strength or extent of Hydrogen bonding present in a substance.

Benzene and chloroform do not have hydrogen bonding being non-polar molecules.

Water has hydrogen bonding being polar.

However acetic acid being the most polar has the maximum hydrogen bonding.

Thus acetic acid has the strongest intermolecular forces of attraction.

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Answer: No, the speed of propagation is constant in a given medium; only the wavelength changes as the frequency changes.

Explanation:

Taking into account the discriminant and quadratic formula:

Zeros or solutions of a function

The points where a polynomial function crosses the axis of the independent term (x) represent the so-called zeros of the function.

That is, the zeros represent the roots of the polynomial equation that is obtained by making f(x)=0.

In summary, the roots or zeros of the quadratic function are those values ​​of x for which the expression is equal to 0. Graphically, the roots correspond to the abscissa of the points where the parabola intersects the x-axis.

The function f(x) = ax²  + bx + c

with a, b, c real numbers and a ≠ 0, is a function  quadratic expressed in its polynomial form (It is so called because the function is expressed by a polynomial).

The following expression is called discriminant:

Δ= b²- 4×a×c

The discriminant determines the amount of roots or solutions of the function.

Then:

The function (x - 4)² - 28 =8 can be expressed as:

(x - 4)² - 28 -8= 0

(x - 4)² - 36= 0

x²- 8x + 16 - 36= 0

x²- 8x + 16 - 36= 0

x²- 8x - 20= 0

Being:

the amount of solutions are calculated as:

Δ= (-8)²- 4×1×(-20)

Δ= 144

As Δ> 0 the function has two real roots or solutions and its graph intersects the x-axis at two points.

In a quadratic function that has the form:

f(x)= ax² + bx + c

the zeros or solutions are calculated by:

[tex]x1,x2=\frac{-b+-\sqrt{b^{2}-4ac } }{2a}[/tex]

The function (x - 4)² - 28 =8 can be expressed as x²- 8x - 20= 0

Being:

the solutions of the function are calculated as:

[tex]x1=\frac{-(-8)+\sqrt{(-8)^{2}-4x1x(-20) } }{2x1}[/tex]

[tex]x1=\frac{-(-8)+\sqrt{144 } }{2x1}[/tex]

[tex]x1=\frac{8+\sqrt{144 } }{2}[/tex]

[tex]x1=\frac{8+12 }{2}[/tex]

[tex]x1=\frac{20}{2}[/tex]

x1= 10

and

[tex]x2=\frac{-(-8)-\sqrt{(-8)^{2}-4x1x(-20) } }{2x1}[/tex]

[tex]x2=\frac{-(-8)-\sqrt{144 } }{2x1}[/tex]

[tex]x2=\frac{8-\sqrt{144 } }{2}[/tex]

[tex]x2=\frac{8-12}{2}[/tex]

[tex]x2=\frac{-4}{2}[/tex]

x1= -2

Finally, the quadratic function (x - 4)² - 28 =8 has two solutions and the solutions are x1= 10 and x2= -2.

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Answer:

Number of valence electrons = Group number of the element on the periodic table.

Explanation:

Hope that helps ^^

A 65.0 g sample of copper at 97.6 °C is added to 46.1 g of water at 20 °C, reaching a final temperature of 24.9 °C.

In physics and chemistry, the law of conservation of energy states that the total energy of an isolated system remains constant; it is said to be conserved over time.

A 65.0 g (m) sample of copper is cooled from 97.6 °C to 24.9 °C. Given that its specific heat (c) is 0.20 J/g.°C, we can calculate the heat (Q) lost using the following expression.

Q(Cu) = c(Cu) × m(Cu) × ΔT

Q(Cu) = (0.20 J/g.°C) × 65.0 °C × (24.9 °C - 97.6 °C) = -945 J

We will use the law of conservation of energy.

Qw + Q(Cu) = 0

Qw = -Q(Cu) = 945 J

We will use the same expression as in Step 1.

Qw = c(w) × m(w) × ΔT

m(w) = Qw / c(w) × ΔT

m(w) = 945 J / (4.18 J&g.°C) × (24.9 °C - 20 °C) = 46.1 g

A 65.0 g sample of copper at 97.6 °C is added to 46.1 g of water at 20 °C, reaching a final temperature of 24.9 °C.

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Answer:

In general, anions are larger than the corresponding neutral atom, since adding electrons increases the number of electron-electron repulsion interactions that take place. Cations are smaller than the corresponding neutral atoms, since the valence electrons, which are furthest away from the nucleus, are lost.

Explanation:

The ion S⁻² (sulfide ion) is larger than the atom S (sulfur atom).

b. S⁻²

Atoms are composed of a nucleus at the center, containing protons and neutrons, and a cloud of electrons surrounding the nucleus. The size of an atom is determined mainly by the arrangement and energy levels of its electrons.

When an atom gains electrons to become an ion, it undergoes a process called electron gain or electron attachment. In this case, sulfur (S) has six valence electrons (electron configuration: 1s² 2s² 2p⁶ 3s² 3p⁴). It tends to gain two electrons to achieve a stable electron configuration similar to the nearest noble gas, argon (Ar: 1s² 2s² 2p⁶ 3s² 3p⁶). By gaining two electrons, sulfur forms the sulfide ion (S⁻²), which has an electron configuration of 1s² 2s² 2p⁶ 3s² 3p⁶.

When an atom gains electrons to become an ion, it forms a negatively charged ion, and this is the case for S⁻². The extra electrons in the ion's electron cloud cause repulsion, leading to an increase in the ion's size compared to the neutral atom. In other words, the addition of two extra electrons in the S⁻² ion increases its electron cloud's size, making it larger than the S atom.

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Complete combustion of an alkane (methane)

You're essentially burning CH4 in the excess presence of oxygen gas, which results in the liberation of water and carbon dioxide