Which of the following is an example of a chemical change?

a
Boiling water

b
Burning paper

c
Dissolving sugar in water

d
Melting gold

Answers

Answer 1

b. burning paper

hope it helps


Related Questions

Which formula represents Snell's law?
On₁ +sine₁ = n₂+ sing₂
n₁sine₁ =n₂sin82
On₁cose₁ = n₂cose₂
n₁ + cose₁ = n₂+ cose ₂

Answers

Answer:

Snell's Law:    N1 sin θ1 = N2 sin θ2

n1 sine1 = n2 sin 82 fits this description

The formula that represents Snell's law is n₁sinθ₁ = n₂sinθ₂. Thus, the correct solution is option B.

What is Snell's law?

When light rays from one medium enter into another medium (rarer to denser medium), the speed of light rays is decreased when light rays enter from rarer to denser medium. This is called as refraction of light rays.

The laws of refraction give Snell's law. The ratio of the sine of the angle of incidence and the ratio of the sine of the angle of refraction is equal to constant (μ) is called Snell's law.

The Snells law, sin i / sin r = μ, where i is the angle of incidence and r is the angle of refraction. μ is the refractive index of the medium. The refractive index remains constant for the medium.

From the given,

Snell's law is written as, sin i / sin r = n₁/n₂, where n₁ and n₂ is the refractive index of the medium. Thus, n₁sin(i) = n₂sin(r).

Thus, the ideal solution is option B.

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PLE HELP

What is the best description of temperature?

Temperature is the same thing as heat.
Temperature measures the number of Kelvins in a substance.

Temperature is the measurement of kinetic energy (movement of molecules).

Temperature only measures an increase in heat energy.

Answers

Temperature is a measurement of the average kinetic energy of an object’s molecules

which statement best describes balancing equations and the law of conservation of mass?
There are more atoms in the reactants than in the products, and the total mass is the same in the reactants and in
The number of atoms is the same in the reactants and in the products, and the total mass is the same in the
reactants and in the products.
There are fewer atoms in the reactants than in the products, and the total mass is less in the reactants than in the
There are more atoms in the reactants than in the products, and the total mass is higher in the reactants than in
the products
Go

Answers

Answer:

The number of atoms is the same in the reactants and in the products, and the total mass is the same in the reactants and in the products.

Suppose u are running at constant velocity and wish to throw a ball such that you Will catch it as it comes back down.
in what direction should you throw aball relative to you?

Answers

Answer:

straight up

Explanation:

the ball will move at the same speed as you are and in the same direction as you are if you simply throw it straight up as you move

light from proxima centauri takes 4.3 years to reach the earth. How far away is the Proxima Centauri?

Answers

Answer:

4.246 light years

Explanation:

4.246 light years

The closest star, Proxima Centauri, is 4.24 light-years away. A light-year is 9.44 trillion km, or 5.88 trillion miles. That is an incredibly large distance. Walking to Proxima Centauri would take 950 million years.

HOPE IT HELPS.

PLEASE MARK ME AS BRAINLIEST.

Answer:

4.25 light years

Explanation:

a light year is the distance light travels in one year it is equal to 9.461 x 1012 km. alpha centauri A & B are roughly 4.35 light years away from us. proxima centauri is slightly closer at 4.25 light years.

A student rubs one side of an inflated balloon on her hair. This side of the balloon becomes positively charged. Explain this.

Answers

Answer:

Friction

Explanation:

Friction between two conductive objects creates static energy in this example making the hair stick up as if it is connected to the balloon. Hope this helps!

A car accelerates uniformly in a straight line from rest at the rate of 2.3 m/s2. What is the speed of the car after it has traveled 55 m?

Answers

Answer:

The speed is =15.91ms−1. The time is =6.92s

Explanation:

A coil with 50 turns of wire is wrapped around a hollow tube with an area of 3.6 m2. Each turn has the same area as the tube. A uniform magnetic field is applied at a right angle to the plane of the coil. If the field increases uniformly from 0.00 T to 0.88 T in 1.85 s, find the magnitude of the induced emf in the coil. If the resistance in the coil is 5.0 Ω, find the magnitude of the induced current in the coil.

Answers

Hi there!

Using Faraday's and Lenz's Law:
[tex]\epsilon = -N\frac{d\Phi_B}{dt}[/tex]

ε = Induced emf (V)

N = number of loops/turns
Φ = Magnetic flux (Wb)

Magnetic flux is given as:
[tex]\Phi_B = \oint B \cdot dA = B\cdot A[/tex]
Since the area of the loops remains constant, we can take area out of the time derivative. Thus:
[tex]\frac{d\Phi_B}{dt} = A * \frac{dB}{dt} = A * \frac{\Delta B}{\Delta t}[/tex]

Also, since the magnetic field is applied at a right angle to the plane of the coil, that means that the field is PARALLEL to the area vector of the plane of the coil. (points normal to the surface). This means we can disregard the dot product since cos(180) = 1.

Plug in the given values.

[tex]\epsilon = - 50 * 3.6 * \frac{0.88 - 0}{1.85} = -85.622 V[/tex]

The negative sign simply means that the induced emf is in the opposite direction in order to oppose the increase in magnetic flux, so the magnitude is simply:

[tex]\epsilon = \boxed{85.622 V}[/tex]

For the current, we can use Ohm's Law:
[tex]i = \frac{\epsilon}{R}\\\\i = \frac{85.622}{5} = \boxed{17.124 A}[/tex]

An elevator is moving with an acceleration of 2.5 m/s. Find the tension in the cables if the total mass of a man and elevator is 80kg. When;
a) Moving up
b) Moving down​

Answers

The tension in the cables are :  a) 984 N when moving up,

b) 584 N when movng down

Given data:

mass = 80 kg

Acceleration = 2.5 m/s

Determine the tension in the cables

A) When moving up

Tension in the cable = m*g + m*a

                                  = 80 * 9.8 + 80 * 2.5

                                  =  984 N

B) When moving down

Tension in the cable = m*g - m*a

                                  = 80 * 9.8 - 80 * 2.5

                                  = 584 N

Hence we can conclude that the tension in the cable are 984 N moving up and 584 moving down.

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Compared to a soft sound, a loud sound at the same pitch....(check all true statements)

a. has a greater wavelength
b. carries more energy
c. has more speed

Answers

Answer:

One might think of a plucked guitar string - the sound would depend on the original amplitude of the disturbance -

Speed and velocity would still be the same

(b) is correct because the energy transfer depends on the original energy applied.

Explain how the charges on objects determine the electric force between them?

Answers

Answer:

1. Objects with the same charge repel each other

2. The objects in interaction A are farther apart

3. The atoms in glass hold on tightly to their NEGATIVELY charged particles

4. Insulators have high resistance, while conductors have low resistance

5. If the current in circuit Q is greater than the current in circuit B then the resistance in circuit A is LESS THAN the resistance in circuit B

6. The resistor decreases the current by transforming electrical energy into different types

7. Electrical energy from the outlet is converted to heat and light energy for the toaster

8. Energy from the sun might be greater than the energy needs of the house, so some will be stored or wasted

9. The switch is open

10. Load

11. P, Q, R

12. When a current runs through a conductor

13. You're on your own.

Explanation:

(50 Points) Will Mark Brainliest

Explain how an electric current affects the charged atoms in a piezoelectric crystal and how this allows the crystal to push a robotic forward

Answers

Answer:

Certain crystals such as quartz are piezoelectric. That means that when they are compressed or struck, they generate an electric charge. It works the other way as well: If you run an electric current through a piezoelectric crystal, the crystal changes shape slightly.

Explanation:

A ray of light, incident on an equilateral glass prism of refractive index √3, moves parallel to the base line of the prism inside it. Find the angle of incidence​

Answers

As the ray of light moves parallel to the base line of the prism inside it, so angle of refraction = r = 30° (equilateral prism)

Now, we know that:

[tex]{:\implies \quad \sf \sin (i)=\mu \sin (r)}[/tex]

[tex]{:\implies \quad \sf \sin (i)=\sqrt{3}\sin (30^{\degree})}[/tex]

[tex]{:\implies \quad \sf \sin (i)=\dfrac{\sqrt{3}}{2}}[/tex]

[tex]{:\implies \quad \sf \sin (i)=\sin (60^{\degree})}[/tex]

Therefore, angle of incidence is 60°

Given ,

[tex]r = \sqrt{3}[/tex]

Now ,

[tex] \longrightarrow \sin(i) = \sqrt{3} \: \sin(30°)[/tex]

[tex] \: \: \: \: \: \: \: \: \: \: \: \: [/tex]

[tex]\longrightarrow \sin(i)= \sqrt{ \frac{3}{2} }[/tex]

[tex] \: \: \: \: \: \: \: \: \: \: \: \: [/tex]

[tex] \longrightarrow \: i = 60°[/tex]

The angle of incidence is 60°.

a wave with a frequency of 500hz is traveling at a speed of 1000m/s whats the wavelength?

Answers

The answer would be 0.4m

PLS HELP! Answer these questions pls. I will mark BRAINLIEST, FIVE STARS AND THANKS. The second question in the pic has three answers. *50 POINTS!*

Answers

Answer:

First one is hydrogen and oxygen

Second one is color change, solid dissolves, and temperature increases

Explanation:

Electrolysis is the process of using electricity to decompose water into hydrogen and oxygen.

Odors and change of states are physical changes while the rest are chemical changes.

Hope this helped!

For question one it’s Hydrogen and Oxygen!
For the second question , it’s colour change since the temperature increases

For the first one the general idea is that Hydrogen molecules violently react with oxygen when the existing molecular bonds break and new bonds are formed between oxygen and hydrogen atoms. As the products of the reaction are at a lower energy level than the reactants, the result is an explosive release of energy and the production of water

Second one is harder to remember but, changes of state (colour) are physical changes whereas the other changes are purely chemical

Students measure how far a snail can travel per minute. The graph shows their data. What is the speed of the snail?

Answers

Answer:

4.00 cm/min

Explanation:

v=d/t

v=10/2=20/4=30/6=5 cm/min

Which of the following is a function of the cardiovascular system?
A. transportation of oxygen
B. removal of carbon dioxide
C. assistance with immune function
D. All of the above

Answers

Answer:

D

Explanation:

The CV system does all of the above

An object has moved through a distance. Can it have zero displacement? Justify your answer.PLEASE I WILL MARKK AS BRAINLIESTT

Answers

Answer:

Explanation:

yes object can move through a distance  and can have zero displacement  

as displacement is the shortest distance between two points eg: if a person has moved a distance of 20 m and comes back to his original place by moving back 20m in such a case  distance moved by the person is 40m but his displacement is 0 as shortest distance covered by him is 0 as he is in his original place

Yes, it is possible for a body to have traveled a distance yet have a displacement of zero.

Distance traveled by a body is the length of the path covered by it.

On the other hand displacement of a body is the shortest distance between the initial and the final point of a body.

When a body is traveling such that it ends at the point from where it started its journey, it covers a distance but the displacement of the body is zero.

So a body that has moved through a distance can have zero displacement.

Explain why rubbing one side of a metal sphere does not cause it to become charged.

Answers

The reason is that in a metal the charges are free to move inside the material.

(b) After 2.0 second the box is being pulled by a constant force 12 N. Determine the size of frictional forces acting on the box at this time.

Answers

The frictional forces acting on the box at this time will be 2.88 N.

What is the friction force?

It is a type of opposition force acting on the surface of the body that tries to oppose the motion of the body. its unit is Newton (N).

Mathematically, it is defined as the product of the coefficient of friction and normal reaction.

The reaction force on the box is;

R=mg

R=F

R=12 N

The friction force is;

F=μR

F=0.24×12

F=2.88 N

Hence,the frictional forces acting on the box at this time will be 2.88 N.

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Differentiate amihan and habagat

Answers

Answer:

Amihan is known as the Northeast monsoon while Habagat is known as the Southwest monsoon.

Two 74.0-kg hockey players skating at 6.15 m/s collide and stick together.

If the angle between their initial directions was 90 ∘ , what is their speed after the collision?

Answers

If the angle between their initial directions was 90 ∘ , their speed after the collision will be 4.35 m/s.

What is inelastic collision?

When two moving bodies after colliding stick to each other and move together is called the inelastic collision.

In inelastic collision , momentum is remains conserved.

Initial momentum =Final momentum

m₁u₁ +m₂u₂ = (m₁ +m₂ )v

where, u₁ and u₂ represents initial velocities of two hockey players and v₁ and v₂ shows the final velocities.

m₁ =m₂ =m and u₁ = u₂ =u

Substitute the values from the question, we get

2mu = 2mv

u =v

u = v x cos (θ/2)

u = 6.15 cos(90/2)

u = v = 4.35 m/s

Thus, the speed after collision is 4.35 m/s.

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Light does not pass through some materials. What do you think happens
to the energy of photons when photons strike a surface and are
absorbed? What indicators would tell you that the energy of the photons
?
has been transformed?

Answers

Answer:

When an electron is hit by a photon of light, it absorbs the quanta of energy the photon was carrying and moves to a higher energy state. One way of thinking about this higher energy state is to imagine that the electron is now moving faster, (it has just been "hit" by a rapidly moving photon)

A photon is a quantum of EM radiation. Its energy is given by E = hf and is related to the frequency f and wavelength λ of the radiation by. E=hf=hcλ(energy of a photon) E = h f = h c λ (energy of a photon) , where E is the energy of a single photon and c is the speed of light.

Kyle travels at an average speed of 64km/h to get from his home to the Maryborough show. Determine
how many minutes (to 2 decimal places) this would take if the distance Kyle needed to travel was
37.6km.

Answers

t = d : v

t = 37.6 km : 64 km/h

t = 0.5875 h = 35.25 min  

A current of 2A flows for 2minutes through the wire in a motor. (1) how much charge passes through a wire this time​

Answers

Answer:

240 C

Explanation:

Given:

I = 2At = 2 minutes = 120 seconds

To find:

Charge passing through the wire (Q)

Solution: Formula relating Q, I and t is given as:

Q = It Plugging the values of I and t in the above equation, we find:Q = 2 * 120-> Q = 240 C

Thus, 240 Coulomb charge will pass through the wire.

Work _____ energy.
A. reduce
B. reflects
c. transfers
D.stops

Answers

Answer:

b

Explanation:

Answer:

C. transfers.

Explanationbecause ive done this question before lol

According to kinetic theory, which two factors are important for a successful reaction to occur?

Answers

Answer:

Molecules must collide with sufficient energy, known as the activation energy, so that chemical bonds can break. Molecules must collide with the proper orientation.

Explanation:

A collision that meets these two criteria, and that results in a chemical reaction, is known as a successful collision or an effective collision.

How would you throw an egg without breaking it?
A. Boil the egg
B. Throw it against a net
C. Throw it against the rotation of the Earth
D. Freeze the egg

Answers

Answer:

b. throw it against a net i think

A wire carrying 0.244 A of current is
0.0870 m from a compass. How
much magnetic field does it create
there?
[?] x 10!?!T

Answers

The magnetic field created by the wire at the given position is determined as 5.61  x 10⁻⁷ T.

Magnetic field created by the wire

The magnetic field created by the wire is calculated as follows;

B = μI/2πr

where;

μ is permeability of free spaceI is current in the wirer is distance of the wire

B = (4π x 10⁻⁷ x 0.244) / (2π x 0.087)

B = 5.61  x 10⁻⁷ T

Thus, the magnetic field created by the wire at the given position is determined as 5.61  x 10⁻⁷ T.

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what is the radius of the 5th orbital in hydrogen?

Answers

Answer:

So, the radius of fifth Bohr orbital of hydrogen is 1. 3225 nm.

Explanation:

pls mark me brainless hope this helps loves x!

[tex]\\ \rm\Rrightarrow r=0.529\dfrac{n^2}{Z^2}[/tex]

For hydrogen Z=1

[tex]\\ \rm\Rrightarrow r=0.529(5)²[/tex]

[tex]\\ \rm\Rrightarrow r=0.529(25)[/tex]

[tex]\\ \rm\Rrightarrow r=1.3225nm[/tex]

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