Choose all of the examples that show a chemical change.
A) A woodpecker digs in the bark.
B) A dead tree rots on the ground.
C) A forest fire burns a lot of trees.
D) A farmer is cutting logs with an axe.
E) A tree drops rainwater from its leaves.

Answers

Answer 1

Answer:

B and C

Explanation:

Answer 2

Answer:

B) A dead tree rots on the ground.

C) A forest fire burns a lot of trees.

Explanation:

It cannot return the the state it was in before or have the same composition it had before.


Related Questions

why are we always at the center of a rainbow? and why can we see a rainbow?

Answers

Answer:

the sun is directly behind your head

Explanation:

The reason why we can see a rainbow is caused by sunlight and atmospheric conditions

which pair of atoms constitutes a pair of isotopes of the same element?

Answers

Answer:

element with same number of protons but different number of neutrons

brainliest plzzzzz

Four students presented different analogies to describe the formation of an ionic bond.

Student A: A tug of war between seven middle school students and a high school student
Student B: A small dog and a big dog tugging at a bone with equal strength
Student C: Two neighbors carpooling to work
Student D: A group of high school students reading from the same book in the library

Which student presented a correct analogy?

A
B
C
D

Answers

Answer:

the correct answer is A

Explanation:

I took the test!

Answer:

A probably because its ionic

what natural resources are used to make plastic bags

Answers

Answer:patrolieum

Explanation:

2.3g of sodium metal is burned completely in oxygen of air.
(Na =23, O =16, at STP : 32g of O2 has 22.4L)
Find mass of the obtained oxide?
Find volume of the required air?

Answers

Answer:

mass of Na2O= 3.1 grams

volume of O2= 0.56 L

Explanation:

First what you need to do is establish the balanced equation for the reaction that they're giving you. In this case would be:

4Na + O2 > 2Na2O

And then, you can read the stequiometry of the reaction:

4 moles of Na react with one mole of oxygen to produce 2 moles of sodium oxide.

So now you know that you have 2.3 grams of sodium so you have to obtain the quantity of moles that are present in 2.3 grams of sodium. The molar mass the (the grams by which you will have exactly one mole) so all you have to do is divide 2.3g ÷ 23g/mol= 0.1 mol

So here you have 0.1 mol of sodium, and you know for a fact that for each 4 moles of sodium, one mole of oxygen reacts, so you simply divide the quantity of moles of sodium you have by the 4 moles of oxygen present in the balanced equation.

0.1 moles ÷ 4 moles = 0.025.

So for each 0.1 moles of sodium that react, 0.025 moles of Oxygen react.

Now what you need to do is to find the limitant reactor (the reactor that's according to the comparison to the balanced equation is in a smaller ratio to the other element, that would be in excess.

In this case, both elements are in a ratio that respects the balanced equation so neither of them is in excess or is limitant.

Now, to determine the amount of Na2O, you simply know that one mole of oxygen react to produce to moles of sodium oxide, So all you have to do is establish the factor of conversion:

0.025 moles O2 x 2 moles Na2O/ 1 mol O2= 0.05 moles of Na2O

Then you convert that to grams by multiplying 0.05 by the molar mass of Sodium oxide and it will be:

0.05 mol Na2O x 62 g/mol= 3.1 grams of Na2O

Now what you need to do is find the volume by which O2 is reacting in the reaction so you can use the equation of the ideal gas law.

PV=nRT at standard temperature and pressure (273 K and 1 Atm)

P=Pressure

V=Volume

n=Number of atoms

R=constant of gases (0.082 Atm L/ mol K)

T=Temperature

V=nRT/P (because you need to find the volume)

V= (0.025 mol)(0.082)(273 K)/1 atm

V=0.56 L

And there you go :)

Copper has a density of 8.96 g/cm^3. What is the mass of a piece of copper with a volume of 2.62 cm^3?

Answers

Answer:

23.48

Explanation:

Good Luck!

Answer: 23.48 g

Explanation:

formula: mass = density x volume

Volume of copper = 2.62 cm^3

Density of copper = 8.96 g/cm^3

mass = 8.96 x 2.62 = 23.4752

which bond shown are triple bonds

Answers

Answer:

Hey mate.....

Explanation:

This is ur answer.....

A triple bond is made of two pi bonds and one sigma bond. Examples of compounds with triple bonds include nitrogen gas, the cyanide ion, acetylene and carbon monoxide.

Hope it helps!

Brainliest pls!

Follow me! :)

What are 2 substances that can CAN conduct electricity? Plz explain.

Answers

Answer:

[tex]\huge\color{magenta}\boxed{\colorbox{skyblue}{Answer ☘}}[/tex]

thє ѕuвѕtαncєѕ thαt cσnduct єlєctrícítч αrє cαllєd cσnductσrѕ.

thє єхαmplєѕ σf cσnductσrѕ αrє -

ѕílvєr cσppєr gσld

hσpє hєlpful~

~ єхhαuѕtєd zσmвíє

Answer:

There are two categories of materials that are good conductors of electricity: metals and plastics. Metals conduct in the solid state because they contain mobile electrons, or electrons that may move about freely. When a copper wire is utilized in an electrical circuit, electrons pass through it every time the switch is flipped...

Explanation:

Concentracion de las siguientes soluciones

Answers

Answer:

wwwwwwwwww

Explanation:

SERIOUS INQUIRES ONLY
does anyone like pistachio ice cream? fr fr bc like everyone says it’s weird but it’s so good yk like fr. don’t just be answering me for point yo i’ll come after you.

Answers

Answer:

I feel it's an extremely underrated Ice cream flavor!

Explanation:

Answer:

it's pretty good

Explanation:

calculate the volume in dm3 occupied by 26.4 g of carbon dioxide​

Answers

Density of carbon dioxide=1564kg/m^3Mass=26.4g=0.0264kg

[tex]\\ \sf\longmapsto Density=\dfrac{Mass}{Volume}[/tex]

[tex]\\ \sf\longmapsto Volume=\dfrac{Mass}{Density}[/tex]

[tex]\\ \sf\longmapsto Volume=\dfrac{0.0264}{1564}[/tex]

[tex]\\ \sf\longmapsto Volume=1.687m^3=1.69m^3[/tex]

1m^3=1000dm^3

[tex]\\ \sf\longmapsto Volume=1.69(1000)=1690dm^3[/tex]

Rank the following in terms of increasing ionization energy: Sulfur, oxygen, hydrogen, and fluorine.

Answers

Answer:

Ranked from lowest to highest:

Sulfur - 999.6 kJ/mol

Hydrogen - 13.5984 kJ/mol

Oxygen - 13.6181 kJ/mol

Fluorine - 17.4228 kJ/mol

Suppose you have samples of three unknown solids. Explain how you could use their properties to determine whether or not they are ionic solids.

Answers

Given a sample of three unknown solids, we would be able to deduce which are ionic solids by their melting and boiling points, conductivity in water, and the insulation they provide.

What are Ionic solids?An ionic solid is a solid formed by ionic bonds. They are the solid version of ionic compounds, which are held together by strong electrostatic energies.

What properties do they possess?Among their many properties, ionic solids possess high melting and boiling points.These solids are also known to conduct electricity well when dissolved into water, however, this can be tested after melting them as they will not conduct electricity in a solid state.A final property that we can use to identify them is that they provide a good means of insulation.Each of these properties can be tested and will allow us to determine the ionic solids amongst the samples.

Therefore, we can find the ionic solids amongst the samples by testing their melting and boiling points, conductivity in water, and the insulation they provide, given that each of these should provide high values to indicate an ionic solid.

To learn more about ionic solids visit:

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1. Which of the following statements about the properties of elements related to an
atomic emission spectrum are true? Select all that apply. (3 are correct)

Answers

The emission spectrum of an atom consists of limited lines that are unique to a given element.

According to the Bohr model of the atom, energy is absorbed or emitted when an atom moves from one energy level to another. Since energy is quantized, the spectrum of atoms often consists of single lines.

Hence, the true statement about atomic spectrum is that; "the light that an element emits is made up of a limited number of narrow lines that produce a unique pattern or atomic emissions spectrum for that element."

Learn more about atomic spectrum: https://brainly.com/question/2049494

Why are the melting and boiling points of an
element or a compound are called its fixed points.

Answers

Substances having fixed chemical proportions will have fixed boiling and melting points. This is the reason that Pure substances have specific melting and boiling points because their chemical proportions are fixed. Mixtures melt and boil over a range of temperatures

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9. Name the element which has the following numbers of particles:
I

Answers

A. iron

B. iodine

C. Helium

D. calcium

E. lead

F. hydrogen

check your periodic table to see if they are correct

atomic number, proton number and electron are the same

to find neutron = mass number - atomic number

Who has an aesthetic room

Answers

Me I have a aesthetic room

I need help!!!!!!!!!!!!!!!

Answers

Answer:

I think the answer is A.

Explanation:

hope this helps.

Perform the following
mathematical operation, and
report the answer to the correct
number of significant figures.
3.22 x 0.17 = [?]

Answers

Answer:

0.5474

Explanation:

3.22 x 0.17

     \/

322 x 17 = 5,474

[] There are four places "after" the decimal in 3.22 and 0.17 combined, meaning we move the decimal to the right four times in our current answer

-> 5,474 becomes 0.5474

Have a nice day!

     I hope this is what you are looking for, but if not - comment! I will edit and update my answer accordingly. (ノ^∇^)

- Heather

Answer:0.55

Explanation:

3.22 × 0.17 calculated with significant figures is 0.55, which has 2 sig figs and 2 decimals. There are 2 steps to calculate 3.22 × 0.17 with sig figs. 0.55 rounded to 1 sig figs is 0.6.

The paths that planets follow around the sun are called ____ , and they are shaped like an ellipse.

Answers

The path that planets follow around the sun are called orbitals.

The paths that planets follow around the sun are called as orbit, and they are shaped like an ellipse.

What is orbit ?

The orbits of the planets around the sun are elliptical. Kepler, an astronomer, provided a clear definition of these orbits. The three rules he created are referred to as Kepler's laws of planetary motion. It says that every planet does an orbit around the sun.

The plane of Earth's orbit around the sun serves as the definition of the ecliptic. The primary planets of our solar system, their moons, some asteroids, and their orbits all roughly follow this plane.

An orbit is a curved path taken by an object, such as a planet's path around a star, a natural satellite's path around a planet, or a man-made satellite's path around a planet, moon, or asteroid.

Thus, the paths that planets follow around the sun are called as orbit.

To learn more about an orbit, follow the link;

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Which statement does NOT describe subduction zones?

A.
Earthquakes and volcanoes occur at these boundaries.

B.
Old crust is recycled into Earth's mantle.

C.
Volcanic mountains can form at these boundaries.

D.
New crust forms by seafloor spreading

Answers

the answer is C but i might be wrong

what do you think will happen to the kidneys if any of these parts were damaged?

Answers

Answer:

When your kidneys are damage waste products and fluid can build up in your body. That can cause swelling in your ankles nausea weakness poor sleep and shortness of breath. so without treatement the damage can get worse and your kidney may eventually stop working.

kcal/mole
EE E E
SODIUM
1s 2s 2p 3s
118
1091
1653
MAGNESIUM 1s 2s 2p 3s2
175
345
1838
2526
ALUMINIUM
1s 2s 2p 3s 3p
138
434
656
2767
If the valence electrons were removed, what would be the lon charge of the element?
Na =
O-1
+1
0-3
+3

Answers

Answer:

+1

Explanation:

your removing a electron and it was already balanced

what is the empirical formula of cinnamaldehyde?​

Answers

C9H8O. .....................

2870 j of energy is required to heat and boil one gram of water at 20 °c. how much water at this temperature can 7.14 × 1010 j of energy heat and boil?

Answers

Answer:

Explanation:

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The mass of water is equal to 2.48 × 10⁷ g, needs the energy of 7.14 ×10¹⁰ J to heat and boil.

What is the specific heat capacity?

The specific heat capacity can be demonstrated as the quantity of energy needed to increase the temperature by one-degree Celcius in one unit of substance.

The temperature will be changed whenever there is a loss or absorption of energy by any substance.

Q = mCΔT

Therefore, there is a direct relationship between the mass of water and the amount of energy.

m ∝ q

[tex]{\displaystyle {\frac{m_1}{m_2} =\frac{q_1}{q_2}[/tex]

[tex]{\displaystyle {m_2} =\frac{q_2}{q_1} \times m_1[/tex]

Given, the energy required to heat mass(m₂) of water, q₂ = 7.14 ×10¹⁰ J

The energy to heat 1 gram of water, q₁ = 2870 J

[tex]{\displaystyle {m_2} =\frac{7.14\times 10^{14}}{2870} \times 1[/tex]

m₂ = 2.48 × 10⁷ g

Therefore, the mass of water is equal to  2.48 × 10⁷ g.

Learn more about specific heat capacity, here:

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YOU WOULD BE A LITERAL LIFESAVER IF U HELP ME. THANK YOUUUU

Answers

Answer:

160 g

Explanation:

5 x 32 = 160g, but if according to the periodic table u provided it would be 5 x 32.06

Answer:

160.3 g S

Explanation:

Saliva, produced by glands in the mouth, plays an important role in the digestion of food. Saliva contains a chemical, called amylase, that breaks down starch in the food we eat. A scientist conducts an experiment to investigate at which temperatures amylase works the best. He hypothesizes that the reaction will occur fastest if the amylase reaction is conducted near the normal human body temperature of 37ºC (degrees Celsius). In order to test his hypothesis, the scientist measures the reaction rate, which is how fast the amylase breaks down the starch at six different temperatures. The reaction rate is rated on a scale of 0 to 10, with 0 meaning no reaction and 10 meaning the fastest reaction. The results are recorded in the data table.

AMYLASE REACTION RATE BY TEMPERATURE

Temperature (ºC)

Reaction Rate

0

2

20 4
40 10
60 8
80 2
100 0
Based on the data, should the scientist accept or reject his hypothesis?

Answers

Answer:

The digestive functions of saliva include moistening food, and helping to create a food bolus, so it can be swallowed easily. Saliva contains the enzyme amylase that breaks some starches down into maltose and dextrin. Thus, digestion of food occurs within the mouth, even before food reaches the stomach.

Explanation:

Which statement about electronegativity is incorrect?
A) Within a periodic table group, electronegativity increases from bottom to top.
B) Metals generally have higher electronegativity values than nonmetals.
C) Within a periodic table row, electronegativity increases from left to right.
D) Fluorine is the most electronegative atom of all the elements.

Answers

Answer:

A

Explanation:

refer to your text book

what was transferred from the hydrochloric acid to the water molecule

Answers

A proton (H⁺) is transferred from the hydrochloric acid to the water molecule.

What is Bronsted-Lowry theory?

Bronsted-Lowry theory is used to classify acids and bases.

Acid: is a substance that donates H⁺.Base: is a substance that accepts H⁺.

Hydrochloric acid is an acid and when it reacts with water, it transfers an H⁺ ion, according to the following equation.

HCl + H₂O ⇒ Cl⁻ + H₃O⁺

A proton (H⁺) is transferred from the hydrochloric acid to the water molecule.

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Explain why the melting temperature of boron trichloride is much lower than that of sodium chloride​

Answers

Boron trichloride has a simple molecular structure, whereas sodium chloride has a giant ionic lattice structure. The ionic bonding between oppositely charged ions in NaCl is stronger than the covalent intramolecular bonding in BCl3. Therefore, less energy is required to break the intramolecular covalent bonds in BCl3, hence a lower melting temperature
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