Which process is an example of a chemical change?
a. cooking a steak
b. chopping a tree
c. heating a cup of tea
d. drying clothes in the dryer

Answers

Answer 1

Answer:

A is the closest thing. You change the composition of the steak. You don't in any of the others.

Explanation:

Usually when you cook something, you are doing something to the composition of the object being cooked. A steak might not be obvious, but boiling an egg should be.

Chopping a tree is something physical. You are removing mass in such a way that the tree will fall. There's nothing chemical about that.

Heating a cup of tea looks like it might be chemical. After all steam is sometimes given off which looks like it is chemical. It's not. The water in the tea is just changing phase.

Drying clothes in a dryer. Again, this looks like something might have changed. After all the mass of the clothes just became less. But all you are doing is separating two masses (leaving one of them behind).

Answer 2
A Sounds like the most relevant one

Related Questions

How many protons and electrons are in a
Cu 2+ ion?
64
29
A 27 protons, 29 electrons
27 protons, 31 electrons
B
29 protons, 27 electrons
D
29 protons, 31 electrons

Answers

Answer:

B  29 protons, 27 electrons

Explanation:

The given specie is copper ion:

         Cu²⁺  

We are to find the number of protons and electrons it contains.

 The number of protons is the positively charged particles in the atom.

 Electrons are the negatively charged particles in the atom.

The number of protons is the same as the atomic number

Atomic number of copper  = 29

 Number of protons  = 29

 Now;

    Charge  = Number of protons  - Number of electrons

     2  = 29  - number of electrons

     -27  = - number of electrons

 Number of electrons  = 27

What is the frequency of light with a wavelength of 3.2 x 10^-16 m?

Answers

Answer:

f = 0.94 ×10²⁴  Hz

Explanation:

Given data:

Frequency of light = ?

Wavelength of light = 3.2 ×10⁻¹⁶ m

Solution:

Formula:

Speed of light = wavelength × frequency

c = λ × f

c = speed of wave = 3×10⁸ m/s

by putting values,

3×10⁸ m/s  = f × 3.2 ×10⁻¹⁶ m

f  =  3×10⁸ m/s   / 3.2 ×10⁻¹⁶ m

f  = 0.94 ×10²⁴ s⁻¹

f = 0.94 ×10²⁴  Hz (Hz = s⁻¹)

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Water stored in snow and ice can return directly to the atmosphere through the process of sublimation.

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Please select the best answer from the choices provided


T

F

Answers

I believe the answer is true:)
i think it’s true!! not sure

If 11 grams of a gas occupies 5.6 liters at STP, what is its gram molecular mass?

Answers

The molecular mass of gas = 44 g/mol

Further explanation

Given

5.6 Liters of gas

11 gram of gas

Required

The molecular mass

Solution

STP = Standart Temperature and Pressure , 1 atm 273 K

At STP , 1 mol gas = 22.4 L

So mol of 5.6 Liters gas :

= 5.6 : 22.4

= 0.25 moles

The molecular mass of gas :

= mass : mol

= 11 g : 0.25 moles

= 44 g/mol

How many grams of C3H8 are in a 7 L tank at 293 K and 5.45 atm?

Answers

1.59 moles















































112211111111111112

Which kind of energy change occurs when a candle is burning

Answers

Answer:

2 Answers. This would be chemical energy that is converted to heat. The heat from the wick melts the wax which gets absorbed in the wick and then gets burnt (which is really oxidation) to produce heat energy as well as light energy.

Explanation:

A candle must undergo a chemical reaction in order to burn, producing heat and light. As a result, energy changes from chemical energy to heat and light energy. As a result, as a candle burns, chemical energy is transformed into heat and light energy.

What is chemical energy ?

Chemical energy is the energy that is released when chemical substances engage in a chemical reaction and change into other substances. Batteries, food, and gasoline energy are some instances of chemical energy storage media.

A type of potential energy associated with the structural organization of atoms or molecules is known as chemical potential energy. Chemical connections or interactions between molecules may have led to this configuration.

They are broken down into simpler molecules, such as glucose and amino acids, which are then either reassembled and stored in various forms, such as glycogen, or consumed as energy. Chemical energy in food is essential for giving our bodies the fuel they require to keep us alive and active.

Thus, energy changes from chemical energy to heat and light energy.

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Many human activities result in carbon dioxide emissions.
Our carbon footprint is a measure of how much carbon dioxide we each cause to be produced.
(a) Why should we be concerned about our carbon footprint?
(b) Most power stations in the UK burn coal.
Coal was formed from tree-like plants over millions of years.
Suggest why burning wood instead of coal would help to reduce our carbon footprint.

Answers

Answer:

: the average human-driven CO2 emissions per year climbed 1.4%

every household makes about 7 tons worth of Co2

A C02 footprints are produced at such high rates and hurts plants and the environment

B coal is a very inexpensive and efficient way to generate electricity. Since its a large quantity of them which still produces alot co2  unlike wood, burning wood doesn't  produce as much but it's much harder to ignite and get to last because it takes coal almost 100 degrees and wood takes about 700 degrees

Sally is building a list of the types of matter that have energy. She includes liquids on her list because she can see that liquids flow. Is her list complete?

a. yes, her list with just liquids on it is complete
b. no, she should add only gases to her list
c. no, she should add only solids to her list
d. no, she should add gases and solids to her list

Answers

Answer:

I just looked up the types of matter energy has.

Explanation:

I believe the answer is D.

Sally's list of matter that have energy is not complete as all the types of matter have energy as all matter have mass , and mass and energy are related, so she should have added gases and solids to her list.

What is matter?

Matter in chemistry, is defined as any kind of substance that has mass and occupies space that means it has volume .Matter is composed up of atoms which may or not be of the  same type.

Atoms are further made up of sub atomic particles which are the protons ,neutrons and the electrons .The matter can exist in various states such as solids, liquids and gases depending on the conditions of temperature and pressure.

The states of matter are inter convertible into each other by changing the parameters of temperature and pressure.

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Large amounts of an unknown compound were isolated from seawater. The compound contained 32.0 grams ofbromine and 4.9 grams of magnesium. What is its percent composition?

Answers

Answer:

87% bromine and 13% magnesium

Explanation:

The compound contained 32.0 grams of bromine and 4.9 grams of magnesium.

We need to find its percent composition.

Mass of the sample = mass of bromine + mass of magnesium

= 32 g + 4.9 g

= 36.9  g

Percentage composition of bromine,

[tex]\%=\dfrac{32}{36.9}\times 100\\\\=86.7\\\\=87\%[/tex]

The percentage composition of magnesium,

[tex]\%=\dfrac{4.9}{36.9}\times 100\\\\=13.27\\\\=13\%[/tex]

So, its percent composition is 87% bromine and 13% magnesium.

Suppose the body is projected from the ground at 24.5 m/s, 60* above the horizontal. Find the (a) time of flight, (b) range, and (c) maximum height.
helppppppp (ᗒᗣᗕ)՞​

Answers

a. t = 4.33 s

b. R = 53.04 m

c. H = 22.97 m

Further explanation

Given

vo=initial velocity=24.5 m/s

Angle = θ = 60°

Required

(a) time of flight, (b) range, and (c) maximum height.

Solution

Parabolic motion

a. time to flight

t = (2vo sin θ) / g

t = (2 x 24.5 x sin 60) / 9.8

t = 4.33 s

b. range (horizontal range) :

R = (vo² sin2θ )/g

R =(24.5² sin 120)/9.8

R = 53.04 m

c. maximum height

H = (vo²sin²θ)/2g

H = (24.5²sin²60)/2.9.8

H = 22.97 m

Question 2
1 pts
What is the molar mass of Cr2(SO4)3?
O 148.1 g
0 288.0 g
O 344.2 g
0 392.2 g
200.0 g

Answers

Answer:

392g

Explanation:

The given compound is;

         Cr₂(SO₄)₃

To find the molar mass, we sum the atomic masses of the elements in the compounds together.

Atomic mass of Cr  = 52

                           S  = 32

                            O  = 16

So;

 Molar mass  = 2(52) + 3[32 + 4(16)]  = 392g/mol

What is the missing word in the word equation below?
sodium hydrogencarbonate → carbon dioxide + water +

Answers

Answer:

sodium carbonate

Explanation:

Sodium hydrogen carbonate (also known as sodium bicarbonate or bicarbonate of soda) has the chemical formula NaHCO3. When it is heated above about 80°C it begins to break down, forming sodium carbonate, water and carbon dioxide. This type of reaction is called a thermal decomposition.

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Rank the states of matter from the LEAST amount of energy to MOST
amount of energy

A.Liquid, Gas, Solid
B.Solid, Liquid, Gas
C.Solid, Gas, Liquid
D.Gas, Liquid, Solid

Answers

Answer:

The ranking of matter from the LEAST amount of energy to MOST amount of energy is;

B. Solid, Liquid, Gas

Explanation:

The kinetic energy of the particles that make of matter depends on the temperature of the particles and the particles are constantly vibrating

Solid state (Least amount of energy)

In the solid state, the matter is held in solid (rigid) crystal lattice and the particles are rigidly located next to other adjacent particles and stacked up layer by layer

Liquid state (Intermediate amount of energy)

As the temperature of the particles are increased by heating, the particles (atoms and molecules) gain more kinetic energy and their vibration is increased which on further heating, leads to the breaking of the lattice bond of the solid state and the particles are then readjusted to exist side by side rather than being stacked on one another and the assume the liquid state

Upon further heating the particles in the liquid acquire more energy and are  and rather than exist side-by-side, they are able to exist as individual particles in the gaseous form

Gaseous state (Most amount of energy)

From the kinetic theory of matter, the molecules of matter in the gaseous state contains enough energy which is more than the intermolecular forces of attraction such that the particles are able to move and occupy the entire volume of the container in which it is placed

Therefore, the correct option is Solid, Liquid, Gas.

Answer:

gas > liquid > solid

Explanation:

Because I said so,

And I took the test.

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Answers

Answer:

1. Hydrogen gas react with nitrogen gas to produce ammonia.

2. Phosphorus react with oxygen to produce phosphorus pentoxide

3. Iron react with water to produce hydrogen gas and Iron(III) oxide

4. Aluminum react with chlorine to produce aluminum chloride.

5. Zinc sulphide react with oxygen to produce Zinc(II) oxide and Sulphur dioxide

Explanation:

1. H₂ + N₂ —> NH₃

H₂ => Hydrogen

N₂ => Nitrogen

NH₃ => Ammonia

The word equation is:

Hydrogen gas react with nitrogen gas to produce ammonia.

2. P₄ + O₂ —> P₂O₅

P₄ => Phosphorus

O₂ => Oxygen

P₂O₅ => Phosphorus pentoxide

The word equation is:

Phosphorus react with oxygen to produce phosphorus pentoxide

3. Fe + H₂O —> H₂ + Fe₂O₃

Fe => Iron

H₂O => water

H₂ => Hydrogen gas

Fe₂O₃ => Iron(III) oxide

The word equation is:

Iron react with water to produce hydrogen gas and Iron(III) oxide.

4. Al + Cl₂ —> AlCl₃

Al => Aluminum

Cl₂ => Chlorine gas

AlCl₃ => Aluminum chloride

The word equation is:

Aluminum react with chlorine to produce aluminum chloride.

5. ZnS + O₂ —> ZnO + SO₂

ZnS => Zinc sulphide

O₂ => Oxygen

ZnO => Zinc(II) oxide

SO₂ => Sulphur dioxide

The word equation is:

Zinc sulphide react with oxygen to produce Zinc(II) oxide and Sulphur dioxide

3. A chemical reaction produces 3.81g potassium chloride (KCI). How many formula units of potassium chloride are there?* Find molar mass of KCI* Answer:__3.08 E 22 formula units of KCI​

Answers

Answer:

3.81 [tex]\frac{1}{74.55}[/tex] X [tex]\frac{6.02*10^{23} }{1}[/tex] = 3.08 X 10^22

Explanation:

74.55 is the mass

The first mass extinction that occurred between the Paleozoic and the Mesozoic Era,
caused the extinction of which organism?
O Wooly mammoth
O Dinosaurs
O Trilobites
Flying Reptiles

Answers

Answer:

O Trilobites

Explanation:

The first mass extinction that occurred between the Paleozoic and the Mesozoic era caused the extinction of the trilobites.

Extinction are catastrophic events that causes the loss of organisms on the earth surface. Several factors can lead to extinction.

The first mass extinction took place between the Paleozoic and the Mesozoic era. This wiped out one of the most successful organism on the earth surface at that time. They were the trilobites.

Which reactions are the reverse of one another? condensation and addition addition and elimination elimination and condensation substitution and addition

Answers

Answer: addition and elimination

Explanation:

In addition you add and in elimination you remove (or subtract)

The reactions that are the reverse of one another are addition and elimination. Details about types of reactions are as follows.

What is a reaction?

A reaction is the transformation in which one or more substances is converted into another by combination or decomposition.

Reactions can be of different types as follows:

AdditionEliminationSubstitutionCondensation

However, addition and elimination reactions are reverse of one another because addition involves adding substances while elimination involves removing substances.

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What are the homologous series?

Answers

Explanation:

Homologous series are the series belonging to a series of aliphatic organic compounds that differ only by the addition of a CH2 group

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The homologous series Is a family of compounds with the same general formula and similar chemical properties that show a gradual change in physical properties. The alkanes are an example of a homologous series

Does anyone know how to do it

Answers

10. The first

11. When the prefix “mono” is added that element in the chemical formula is not written with a subscript. If the prefix is greater than one you write a subscript in the formula

How many total "elements" are in the chemical equation?
H2 + O2 + H2 → H2O + H2O

1
6
12
2

Answers

Answer:

Two elements

Hydrogen and Oxygen

Give an example of a chemical reaction during which a single substance breaks
down. *

Answers

Answer:

2NaCl(l) => 2Na(s) + Cl₂(g)

Explanation:

Electrolysis of melt NaCl to form sodium (Na) metal and chlorine (Cl₂) gas.

This is a class of reaction called 'Decomposition Rxns'. For what it's worth, there are 6 distinct compound types that undergo breakdown by decomposition. The acronym C O A C H E can help remember them.

C - Carbonates => CaCO₃(s) => CaO + CO₂

O - Oxides of Metals => 2Fe₂O₃(s) => 4Fe°(s) + 3O₂(g)

A - Acids (Oxoacids) => H₂CO₃(aq) => CO₂(g) + H₂O(l)

C - Chlorates, Bromates & Iodates => 2KClO₃(s) => 2KCl(s) + 3O₂(g)

H - Hydroxides => Ca(OH)₂(s) => CaO(s) + H₂O(l)

E - Electrolysis => see above electrolysis of NaCl(l)

Answer:

2NaCl(l) => 2Na(s) + Cl₂(g)

Explanation:

An anion (negatively charged atom) contains...

Answers

2. more protons than electrons

How are sodium (Na) and potassium (K) similar?
A. They rarely react.
B. They are highly reactive.
C. They are hard metals.
D. They are soft nonmetals.

Answers

Answer:

B. They are highly reactive.

Explanation:

Answer:

B: They are highly reactive

Explanation:

Sodium(Na) and potassium(K) are in the same family/group which is the Alkali Metal group.  These groups have their ability to displace H2(g) from water and create a basic solution. Alkali metals are also known to react violently and explosively with water. This is because enough heat is given off during the exothermic reaction to ignite the H2(g). Therefore, they are similar because of their reactivity.

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What is the percentage composition for H2O in this compound Al(OH)3.2H2O?

a
50.55%
b
40.05%
c
32.73 %
d
65.09%

Answers

Answer:

32.73%

Explanation:

To solve this problem, first find the molar mass of Al(OH)₃.2H₂O

 Atomic mass of Al  = 27g/mol

                            O = 16g/mol

                            H  = 1g/mol

Molar mass = 27 + 3(16 + 1) + 2(2(1) + 16)

                    = 27 + 51 + 36

                   = 114g/mol

Percentage composition  = [tex]\frac{36}{114}[/tex] x 100 = 32.73%

A student decides to dissolve crackers in their soup as fast as possible. They must first increase the surface area of the crackers. How could this be done? a.Break the crackers into pieces b.Pile the crackers on top of each other c.Wrap the crackers in plastic to keep them fresh d.Put crackers in the bottom of the bowl

Answers

Answer: The correct option is A ( Break the crackers into pieces.)

Explanation:

The rate of reaction between two substances can be affected by the following factors:

--> surface area of reacting substances

--> concentration

--> reaction mechanism

--> temperature

--> the presence of a catalyst and

--> pressure ( if gaseous)

Reagents in solution tend to react faster than reagents in solid form. This is because molecules are freer to move about and collide more effectively in solutions. For example, a lump of zinc will not react as fast as powdered zinc with dilute hydrochloric acid to produce hydrogen. This is the same with the reaction between the crackers and soup. To increase the reaction of the substances, the crackers needs to be broken into pieces(thus,increased surface area)

Atoms gain or lose valence electrons until they have the same number of valence electrons as the closest atmospheric gas

Answers

it loses valence electrons

PLZ HELP!!!!!asapnow

Answers

Answer:

Friction of wind against the ocean surface

friction of wind against the ocean surface

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The Earth's surface is _____ water.

50 %

71 %

97 %

Answers

Answer:

71%

Explanation:

71% explanation: About 71 percent of the Earth's surface is water-covered, and the oceans hold about 96.5 percent of all Earth's water. Water also exists in the air as water vapor, in rivers and lakes, in icecaps and glaciers, in the ground as soil moisture and in aquifers, and even in you and your dog. Water is never sitting still.

Calculate the number of grams of solute in 814.2mL of 0.227 M calcium acetate

Answers

Answer:

Mass = 29.23 g

Explanation:

Given data:

Volume of solution = 814.2 mL 814.2/1000 = 0.8142 L)

Molarity of solution = 0.227 M

Mass of solute in gram = ?

Solution:

Molarity = number of moles / volume in L

By putting values,

0.227 M = number of moles / 0.8142 L

Number of moles = 0.227 M × 0.8142 L

Number of moles = 0.184 mol

Mass in gram:

Mass = number of moles × molar mass

Molar mass of calcium acetate = 158.17 g/mol

Mass = 0.184 mol × 158.17 g/mol

Mass = 29.23 g

Increasing the temperature of a given amount of gas at constant volume causes the pressure to increase because _____. there is less space where the molecules can move around there are more molecules the molecules are striking a larger area with less force the molecules are moving more quickly

Answers

Answer:

the molecules are moving more quickly

Explanation:

The  relationship between temperature and pressure is explained using the kinetic theory of matter.

As the temperature of the gas is increased, the molecules have a greater kinetic energy. This increased energy of the gas molecules make the collision between the molecules and with the walls of the container more rapid.

The correct option is;

the molecules are moving more quickly

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