Which example illustrates a chemical change

shredding paper
smashing a soda can
burning wood
chopping wood

Answers

Answer 1
burning wood because heat indicates a chemical change
Answer 2
burning wood since it is changing into a new substance, whereas the other examples are not

Related Questions

What is your carbon footprint?

the amount of carbon dioxide you use when recycling
the amount of oxygen put into the atmosphere due to your consumption of fossil fuels
the amount of carbon dioxide and oxygen in the atmosphere at any given time
the amount of carbon dioxide put into the atmosphere due to your consumption of fossil fuels

Answers

Answer:

c. .....................

Answer: the amount of carbon dioxide put into the atmosphere due to your consumption of fossil fuels

Your carbon footprint is the amount of carbon dioxide and other carbon compounds emitted, because of your use of fossil fuels.

Hope this helps!

Write the principle of separation of mixture.

Answers

Explanation:

Mixtures can be separated using a variety of techniques. Chromatography involves solvent separation on a solid medium. Distillation takes advantage of differences in boiling points. Evaporation removes a liquid from a solution to leave a solid material.

An acid-base reaction of (r)-sec-butylamine with a racemic mixture of 2-phenylpropanoic acid forms two products having different melting points and somewhat different solubilities. Draw the structure of these two products. How are the two products related? Be sure to answer all parts.

Answers

Answer:

See explanation

Explanation:

When an optically active compound reacts with a racemic mixture, two different products appear .

Hence, when (R)-sec-butylamine reacts with a racemic mixture of 2-phenylpropanoic acid as shown in the image attached.

Enantiomers are optical isomers which are mirror images of each other. The image attached was obtained from Bartleby.

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Q7. Pb + O2 PbO2

Is this combustion, single replacement, double replacement, synthesis, or decomposition

Answers

Answer:

This is a synthesis reaction.

Explanation:

Two elements are bonded together to form (synthesize) a new compound.

1. Compare and contrast the characteristics of metals and nonmetals.
2. Describe the electrochemical series and why it’s important in understanding metals.
3. Describe the theory of ionization in regard to acids and bases.
4. Identify the role of indicators.

Answers

Answer:

1. Both metals and nonmetals are types of elements and can be involved in chemical reactions. Some of their differences are highlighted in the chart below.

  Metals:    

Appearance; Shiny.    

Conduct heat or electricity; Yes.  

Malleable or ductile; Yes, both and has great mechanical strength.    

Form stable compounds; Forms stable compounds with acids; also forms oxides; replaces hydrogen in acids or water; combine with nonmetals; often becomes positive.

  Nonmetals :  

Appearance; Not shiny .  

Conduct heat or electricity; Not well .  

Malleable or ductile; Brittle and not easily molded into shapes .  

Form stable compounds; Oxides usually give acid reactions in water; often becomes negative

2. The electrochemical series is an arrangement of metals in such order that any metal in the list is displaced from its compounds by any metal above it, but displaces any metal below it. The higher up the list a metal is, the greater its activity. Knowing a metal’s placement on this chart can help you understand the activity of the metal, especially in regard to its ability to displace hydrogen in acids. Any items on the list far above hydrogen will do a good job at displacing it, those near it won’t do such a good job, and those below it won’t displace it from acids at all.

3. When placed in water, acids dissociate and form free hydrogen ions, which determine the properties of acids. The number of hydrogen ions determines the strength of an acid. Strong acids dissociate to a large degree and produce a large number of hydrogen ions. Weak acids dissociate to only a slight degree.

When placed in water, bases dissociate and form free hydroxyl ions, which determine the properties of bases. Strong bases dissociate to a great degree and produce a large number of hydroxyl ions. Weak bases dissociate to only a slight degree.

When free hydrogen ions and free hydroxyl ions are removed from solutions of acids and bases, then the acidic and basic properties disappear. This is what happens when acids and bases are mixed together in proper proportion; the hydroxyl ion will unite with the hydrogen ion to form water. The resulting salt product is neutral.

4. Indicators are used to help determine the pH value of an unknown solution. These are often papers that turn a certain color at certain pH values.

Metals are good conductors of heat and electricity but the non-metals are not.

Compare metals and non-metals

Metals are good conductors of electricity and heat whereas non-metals are poor conductors of heat and electricity. Metals have high density while on the other hand, non-metals have low density. Metals are malleable and ductile whereas non-metals are brittle.

So we can conclude that metals are good conductors of heat and electricity but the non-metals are not.

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1. An atom has 57 neutrons and 42 protons. How many electrons will this atom have if it
neutral?
57
44
42
40

Answers

Answer:

42

Explanation:

Because the proton number or atomic number is equal to electron number.

Answer:

42

In order for it to be neutral there must be the same amount of protons and neutrons

Have a nice day!   :)

What phenomenon does the Coriolis effect arise from?

Answers

Answer:

because our planet is spinning

which means the objects near the equator are moving at much faster velocities than objects at higher latitudes

I hope this helps✌

the percent composition of calcium is ?

Answers

Answer:

36%

Explanation:

This is the answer on edmentum/plato. Hope this helps. Jesus loves YOU!

Solve for Keq , given the following concentrations at equilibrium. Based on the calculated Keq, are products or reactants larger?
CO2 = 3.0 M O2 = 1.5 M CO = 2.0 M

Answers

Answer:

it blows up very lighty

Explanation:

Jamal is 8 miles away from his house. He rides his bike home toward home at a speed of 12 mph..

How far away from home is he after a half hour?

Answers

Answer: 2miles

Explanation:if he’s going 12 miles in one hour, in half an hour he would’ve made it 6 miles. 8-6=2

Answer: b. 2 miles

Explanation:

Does anybody understand this I’m stuck

Answers

Answer:

it's the first one

Explanation:

can you help me too

The answer is d I think

Which best explains how photosynthesis is helpful to humans? OIt reduces the amount of harmful rays released by the sun. O It increases the levels of carbon dioxide in the air. O It provides oxygen for humans to breathe. OIt produces proteins, which humans can eat.​

Answers

Answer:

C. sorry i am late :)

Explanation:

During photosynthesis, plants intake carbon dioxide from the air and releases oxygen. Thus, they are providing enough oxygen available for humans to breath.

What is photosynthesis?

Photosynthesis is a bio-chemical process by which green plants produces chemical energy with the aid of light energy absorbed by chlorophyll. Photosynthetic reaction is the combination of carbon dioxide and water giving molecular oxygen and glucose.

Through photosynthesis, the amount ox oxygen and carbon dioxide in the atmosphere is balanced. This balancing cycle involves respiration of animals also.

The carbon dioxide that we exhale are up taken by plants and converts to oxygen gas. This makes sufficient oxygen for all animals to breath. Therefore, photosynthesis is a stage in carbon cycle and oxygen cycle.

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Consider the reaction below. 2 Upper N Upper H Subscript 3 (g) Baseline double headed arrow Upper N Subscript 2 (g) Baseline + 3 Upper H Subscript 2 (g). What is the most likely effect to the forward reaction if there is an increase in pressure on this reaction? The reactant surface area increases. The reaction rate decreases. The reaction is not affected at all. The reaction stops completely.

Answers

Answer:

The increase in pressure of the reacting system will increase the formation of NH₃

Explanation:

The given parameters are;

2NH₃ (g) ⇄ N₂ (g) + 3H₂ (g)

The number of molecules in the reactant side of the equation = 2 molecules

The number of molecules in the product side of the equation = 1 + 3 = 4 molecules

Avogadro's law states that equal volume of all gases at a given temperature and pressure contains equal number of molecules

Therefore, given that the number of molecules of the product are twice the number of molecules of the reactant, the volume of the product is twice the volume of the reactant

If the pressure is increased, at constant temperature by Boyles law, the volume will be reduced, favoring the formation of the low volume occupying NH₃

Therefore, the reverse reaction (formation of NH₃) will preferably occur.

Answer:

The answer is B

Explanation:

The other answer is incorrect. The correct Answer is B

Trust Me

Which statement best defines potential enregy?

A. Potential energy is stored energy.

B. Potential energy is energy that can change over time.

C.Potential energy is the energy of motion.

D. Potential energy is the type of energy a roller coaster uses.

Answers

Answer:

A. Potential energy is stored energy

Explanation:

Answer:

A

Explanation:

i have the same question

which balances the equation Mg + O2 → MgO

Answers

Answer:

2Mg+[tex]O_{2}[/tex]→2MgO

Explanation:

The first step is magnesium + oxygen equals magnesium oxide

The second step is changing that into an equation which looks like Mg+[tex]O_{2}[/tex]→MgO

The third step is to 2*Mg and 2*O as well as the product has to be 2*Mg,2*O which gets the equation to become balanced as 2Mg+[tex]O_{2}[/tex]→2MgO

The coefficient 2 balance the given reaction. The balanced equation for the given reaction is given as [tex]\rm Mg + O_2 \rightarrow 2MgO[/tex].

A balanced equation is a mathematical representation of a chemical reaction that respects the law of mass conservation. It depicts the reactants and products of the reaction, as well as the relative amounts of each species. The unbalanced equation is [tex]\rm Mg + O_2 \rightarrow MgO[/tex]. One magnesium (Mg) atom on the left side and one on the right side, so the magnesium is already balanced. Balance the oxygen (O) atoms. On the left side, there are two oxygen (O) atoms present in the O2 molecule. On the right side, there is only one oxygen (O) atom in the MgO molecule. To balance the oxygen atoms, we need to add a coefficient of 2 in front of MgO: [tex]\rm Mg + O_2 \rightarrow 2MgO[/tex]. The balanced equation is [tex]\rm Mg + O_2 \rightarrow 2MgO[/tex].

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Each water molecule can form hydrogen bonds with up to _____ neighbors

Group of answer choices

6

8

2

4

Answers

Answer:

2

Explanation:

thats the answer.have good day

Please help will give brainliest

Answers

Answer:

6 g/cm³

Explanation:

Hi there !

density formula

d = m/V

V = 33.0ml - 25.0ml = 8.0 ml = 8 cm³

m = 48.0 g

replace

d = 48g/8cm³ = 6 g/cm³

Good luck !

Two liters of hydrogen gas are stored at a
pressure of 100 kPa. If the temperature
does not change, what will the volume
of the gas be when the pressure is
decreased to 25 kPa?

Answers

Answer:

the volume will expand

Explanation:

gas under pressure contracts, and expands with a lesser pressure

The volume of the hydrogen gas at 25 kPa is 8 Liters.

Explanation:

Given:

At constant temperature, 2 liters of hydrogen gas at 100kPa pressure.

To find:

The volume of the hydrogen gas at 25kPa.

Solution:

The initial pressure of the hydrogen gas =[tex]P_1=100 kPa[/tex]

The initial volume of the hydrogen gas at 100 kPa =[tex]V_1=2 L[/tex]

The final pressure of the hydrogen gas =[tex]P_2=25 kPa[/tex]

The final volume of the hydrogen gas at 25kPa = [tex]V_2=?[/tex]

Using Boyles law:

[tex]P_1V_1=P_2V_2\\100kPa\times 2 L=25 kPa\times V_2\\V_2=\frac{100 kPa\times 2L}{25 kPa}=8L[/tex]

The volume of the hydrogen gas at 25 kPa is 8 Liters.

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Which is the smallest?
A) 1.3 x 1020
B) 2.9 x 1021
C) 9.5 x 1032
d) 8.4 x 1019

Answers

Answer: A, 1.3*1020, 1326

A. 1326

B. 2960.9

C. 9804

D. 8559.6

Why is it easy for some elements to lose electrons and harder for others?

Answers

Answer:

The further away electrons are from the nucleus the easier it is for atoms to use electrons.

Explanation:

PLEASE HURRY WILL GIVE BRAINLIEST

Click Oil Basics and use the information to complete this passage that discusses how plastic production affects society.

The production of plastics makes life
{answer} , so it benefits society. On the other hand, the production of plastics causes air and water {answer} , so it also harms society.

Answers

Answer:

easier and pollution

Explanation:

I just had this question and got it right

How do combination circuits help prevent problems in circuits in a home? If it helps, think about a bedroom since all electrical work in a bedroom is on the same circuit.

Answers

‍♀️ ◻️✅◾️▫️‍◾️◻️◻️◼️

Which molecules of the following gases will
have the greatest average kinetic energy?
1. N2 at 1 atm and 298 K
2. CO2 at 1 atm and 298 K
3. H2 at 0.5 atm and 298 K
4. He at 0.1 atm and 298 K
5. All of the molecules have the same kinetic
energy

Answers

Answer:

.

Answer: 5 All of the molecules have the same kinetic energy

since the temperature is kept constant at 298 K

Explanation:

The AVERAGE kinetic energy is directly proportional to the absolute temperature.

All the molecules have the same average kinetic energy as average kinetic energy is directly proportional to the absolute temperature. So, the correct option is 5.

What is average kinetic energy?

The average kinetic energy (K) is equal to one-half of the mass (m) of each gas molecule times the root mean square speed (Vrms) squared.

We know that the average kinetic energy is directly proportional to the absolute temperature.

All of the molecules have the same kinetic energy since the temperature is kept constant at 298 K.

Therefore, All the molecules have the same average kinetic energy as average kinetic energy is directly proportional to the absolute temperature.

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Through what process is heat transferred between the warmpair in front of a
fireplace and the cooler air on the other side of the room?
A. Radiation
B. Conduction
C. Convection
D. Absorption

Answers

Answer:

c-convection

Explanation:

i think it may help you and if its helpful plzz mark as brilliant

Convection this is when warm air and cold air are in a cycle

14. How do you describe an atom in which the number of protons is equal
to the number of electrons?

Answers

the number of protons in the nucleus of the atom is equal to the atomic number (z) and the number of electrons in a neutral atom is equal to the number of protons

____ energy is the energy a roller coaster stores while moving to the top of a hill.

A. G-Force

B.Potential

C. Stirred

D. Kinetic

Answers

Answer:

B

Explanation:

trust me im 100% correct

If air temperature decreases, then
wave height will decrease
ocean temperature will also decrease the same amount
ocean temperature will also decrease, but not as much
ocean temperature will also decrease, but a greater amount
wave height will increase

Answers

Answer:

ocean temp

Explanation:

If air temperature decreases, then wave height will decrease and ocean temperature will also decrease, but not as much.

What is ocean temperature ?

The water's temperature at the surface is known as the ocean surface temperature. Depending on the measuring technique, the term "surface" might signify anything from 1 millimeter to 20 meters below the sea's surface.

Due to changes in solar radiation and the physical characteristics of water, the temperature of ocean water fluctuates depending on location, both in terms of latitude and depth.

Water contracts and gets denser as it cools. The density of water is influenced by temperature and salinity, and as a result, water moves up or down through the ocean's strata and circulates as currents.

Thus, option B is correct.

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A sealed 512 cm3 flask is full to capacity with 16 g of a substance. Determine the density of the substance.​

Answers

Answer:

The answer is 0.031 g/cm³

Explanation:

The density of a substance can be found by using the formula

[tex]density = \frac{mass}{volume} \\[/tex]

From the question

mass = 16 g

volume = 512 cm³

We have

[tex]density = \frac{16}{512} = \frac{1}{32} \\ = 0.03125[/tex]

We have the final answer as

0.031 g/cm³

Hope this helps you

I need help on Chemistry?

ANYONE PLEASE?

Answers

Answer:

1. 1g/ml

Explanation:

1. Density is mass divided by volume (g/mL).

10g/10mL = 1 g/mL

2. When you already know the density and the volume, you can use the density as a unit converter.

[tex]5mL*\frac{20g}{mL} = 100g[/tex]

3. It's the same with density and mass.

[tex]20g*\frac{1mL}{5g} = 4mL[/tex]

You just got a free ticket for a boat ride, and you can bring along
2 friends! Unfortunately, you have 5 friends who want to come along.

Answers

Answer:

10

Explanation:

Khan Academy

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