What is evidence that a chemical change has happened?
O A. The temperature of a substance increases or decreases.
B. The amount of matter increases.
C. A substance changes into a new kind of substance.
O D. You observe a color change.

Answers

Answer 1
i think the answer is D

Related Questions

can someone solve this plz
βeta decay
carbon atomic mass 14
atomic # 6

Answers

Answer:

14/6C your welcome

Explanation:

Metals react by losing valence electrons. Which of the alkali metals loses its valence electrons most easily? Explain.

Answers

Answer:

lol you have an aot profile pic

Is cell membrane a plant or animals cell

Answers

Answer:

They both have a cell membrane, however a plant also has a cell wall.

Explanation:

need helpppppp hurry pls, i just really need help

Answers

Answer:

6.8 mole of O₂

Explanation:

Given expression:

       2H₂   +   O₂   →   2H₂O

Number of moles of H₂ = 13.6moles

Unknown:

Number of moles of O₂  = ?

Solution:

In the given problem, we are to find the number of moles of oxygen gas that will use up 13.6mole of hydrogen gas;

 From the reaction equation;

             2 mole of H₂ will completely react with 1 mole of O₂

         13.6 moles of H₂ will completely be used up by [tex]\frac{13.6}{2}[/tex] mole of  O₂

                                                                                        = 6.8 mole of O₂

Which element wants to gain valence electrons while bonding?
a. Neon (Ne)

b. Fluorine (FI)

c. Lithium (Li)

d. Magnesium (Mg)

Answers

Answer:

b. Fluorine (FI)

Explanation:

From the given choices, only fluorine wants to gain valence electrons while bonding.

This is because fluorine is the most electronegative specie from the given choices. An electronegative substance have a high tendency to attract electrons to itself in a bond.

Neon is a noble gas and it is stable. Lithium and Magnesium are metals that are electropositive. They prefer to lose electrons than to gain electrons.

the first 5 elements (in increasing order) that are found in group 18

Answers

Answer:

Today, I will present the first eighteen elements which are Hydrogen, Helium, Lithium, Beryllium, Boron, Carbon, Nitrogen, Oxygen, Fluorine, Neon, Sodium, Magnesium, Aluminum, Silicon, Phosphorus, Sulfur, Chlorine, and Argon.

First 5: Hydrogen. The first and simplest element on the periodic table.

Helium. a very light colorless element that is one of the six inert gasses.

Lithium. A very soft, light metal.

Beryllium. A very light metal; although it is 3 1/2 times the density of Lithium.

Boron. The fifth element in the periodic table.

Explanation:

the diagram below shows three containers of gas.
Which list correctly describes the gases in containers R, S, and T?

a R= element s = compound t = mixture
b R= compound s = element T= mixture
cR= element s = mixture t= compound
d r = mixture s= emelem t = compound
ASAP

Answers

Answer:

d

Explanation:

The correctly describes the gases in containers R, S, and T is  R = mixture S = element and  T = compound. Hence option d is correct.

What are gases?

Gases are defined as the state of matter where particles often travel very swiftly, far apart from one another, and with little or no attraction to one another. They take up much more space than the liquids or solids from which they are formed, are simple to compress, and expand to fill their containers.

Particles make up all matter; these particles can be single atoms or atoms that have been chemically combined to form molecules. This fact allows us to divide matter into three general categories: elements, compounds, and mixtures. All the atoms in an element are of the same kind. A compound is created when more than one kind of atom is chemically bonded.

Thus, the correctly describes the gases in containers R, S, and T is  R = mixture S = element and  T = compound. Hence option d is correct.

To learn more about gases, refer to the link below:

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Butane and methyl propane are an example of a pair of

Answers

They are a pair of structural isomers because they both have the same chemical formula of C4H10 ingrained in each other
The answer is isomers pair

The data table below shows four different chemical reactions, the temperature change of each, and the duration of the change in temperature. Based on this data, which reaction would be classified as an exothermic reaction? Explain your answer. ALL TEMPS ARE IN CELSIUS
Reaction 1: temp change: -25 degrees; duration of temp change: 25 mins
Reaction 2: temp change: -23 degrees; duration of temp change: 15 mins
Reaction 3: temp change: -30 degrees; duration of temp change: 25 mins
Reaction 4: temp change +22 degrees; duration of temp change: 30 mins

Answers

Answer:

Reaction 4

Explanation:

exothermic reaction is reaction in which reaction takes place evolving heat

Answer:

NO

Explanation:

the reson is because nobody wanna answer my questions

HELP DUE TOMMOROW! FAILING CLASS!!! When it would be appropriate to use Radiocarbon dating, Rubidium-Strontium dating, Uranium-Lead dating, and Potassium-Argon dating. Include if the types of dating are used for organic or inorganic things and the time range they are useful for.

Answers

Answer:

Uhm if you're failing the class why are you still using brainly to get answers... Where's your momma boy?

Explanation:

It izzz what it izzz

The Environmental Protection Agency and health officials nationwide are concerned about the levels
of Radon gas in homes. The half-life of Radon-222 isotope is 3.8 days. If a sample of gas taken from
basement contains 4.38 ug of Radon-222, how long will it be until 0.55 ug will remain? How many half lives?

Answers

It takes 11.4 days⇒three half-lives

Further explanation

General formulas used in decay:  

[tex]\large{\boxed{\bold{N_t=N_0(\dfrac{1}{2})^{t/t\frac{1}{2} }}}[/tex]

T = duration of decay  

t 1/2 = half-life  

N₀ = the number of initial radioactive atoms  

Nt = the number of radioactive atoms left after decaying during T time  

t1/2=3.8 days

No=4.38 μg

Nt=0.55 μg

[tex]\tt 0.55=4.38\dfrac{1}{2}^{t/3.8}\\\\0.125=\dfrac{1}{2}^{t/3.8}\\\\\dfrac{1}{2}^3=\dfrac{1}{2}^{t/3.8}\\\\3=t/3.8\rightarrow t=3.8\times 3=11.4~days[/tex]

Calculate the percent composition of C6H12O6

Answers

Answer:

Did you just let your cat walk on your keyboard? XD

Could you explain this a bit better please?

I'll answer the question in the replies of this comment if you can give me a bit more information.

Explanation:

May I have brainliest please? :)

Analyze how friction can be both a positive and negative aspect in our everyday lives. Use examples to support your statements.

Answers

Answer:

For example, friction between our shoes and the floor stop us from slipping and friction between tyres and the road stop cars from skidding. Friction is sometimes unhelpful. For example, if you don't lubricate your bike regularly with oil, the friction in the chain and axles increases.

Explanation:

A 23.7 g piece of iron at 54.9°C is cooled and releases 338 J of heat. The specific heat of iron is 0.450 J/g°C.

Answers

Answer:

The heat capacity and the specific heat are related by C=cm or c=C/m. The mass m, specific heat c, change in temperature ΔT, and heat added (or subtracted) Q are related by the equation: Q=mcΔT. Values of specific heat are dependent on the properties and phase of a given substance.

Explanation:

Answer:

23.2 degrees c

Explanation:

how can you use these materials to test whether land or water heats faster?

Materials:
sand
water
heat lamps
thermometers
cups

Answers

Answer:

Put sand in one cup and water in the other. Put two heat lamps at equal height and under each one put the water and sand, this must be done at the same exact time. Set a timer for 5, then 10, then 15, and so forth minutes. Each time measure the temperature of each with the thermometers and write the down. Have a certain temperature you want them to get to and see which gets to it quicker. Then set a new temp 3 times to see if the answer is consistent.

Explanation:

Doing this would test whether land or water heats quicker.

Answer:

heat lamps

Explanation:

How many moles of carbon dioxide molecules
are there in 50g of carbon dioxide?

Answers

Answer:

3.011×1023 individual carbon dioxide molecules

When the moon is between the earth and the sun what moon phase will this be

Answers

Answer: New Moon Phase

Explanation:

Answer:

The New Moon phase

Explanation:

The moon in between the earth and the sun will cause it being a new moon because the sun's light doesn't reach the side of the moon thats facing the earth

Time Period Duration (Millions of Years ago)

Cenozoic 66-0

Mesozoic 252-66

Paleozoic 541-252

Trilobites appeared approximately 521 years ago and disappeared approximately 250 million years ago. During which era did the trilobites live?

a
Cenozoic
b
Mesozoic
c
Paleozoic
d
None of These

Answers

Answer:

B

Explanation:

The chemical equation below shows the amount of the reactants used and the amount of only one of the products formed. How much water (H2O) should be formed in this chemical reaction? CH4 mass 4 + 2O2 mass 16 CO2 11 + 2h2O mass ?

Answers

Answer:

CH4 + 2O2 → CO2 + 2H2O

Explanation:

This is all i could come up with im sorry.

The amount of water formed in the given chemical reaction is 9 grams.

What is Stoichiometry?

Stoichiometry is the calculation for the determination of the relative amount of reactants and products in chemical reactions. Stoichiometry is based on the law of conservation of mass where the total mass of the reactants in reaction equals the total mass of the products.

If the quantity of one reactant is known and the quantity of the product can be determined empirically, then the quantity of the other reactants can be calculated.

Given chemical equation is:

CH₄  +   2O₂  [tex]\longrightarrow[/tex]   CO₂   +   2H₂O

16g        32g         44g           32g        (from their molecular masses)

The amount of methane, oxygen, and carbon dioxide is 4g, 16g, and 32 g respectively.

16g of methane react with oxygen = 32g

4g of  methane will react with oxygen = 8g

It means here methane is the limiting reagent as the given amount of oxygen is more than reacted one.  So CH₄ will decide the amount of water.

16g of methane produces water = 32g

Then 4g of methane will produce water = (32/16) × 4 = 9 g

Therefore, 9 grams of water should be formed in this reaction.

Learn more about Stoichiometry, here:

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What is the change in entropy (AS) when sodium chloride dissolves in water?​

Answers

Answer:

D. Greater than 0

Explanation:

Sodium chloride(NaCl) in water is a endothermic reaction, which means the heat is absorbed.

Carbon makes up part of all life forms on Earth. The human body, for example, is about blank % carbon.​

Answers

about 18% of the human body is made of carbon!!! hope this helps!

What is the role of CdKs? to create enzymes that produce chemical changes to signal the cell to move to the next phase of the cell cycle to build structural components of DNA and energy-rich substances to activate the cyclins that cause progression of the cell cycle

Answers

Answer:

It’s b

Explanation:

Answer:

Regulation of the cell cycle is carried out by which of the following? Check all that apply.

CdKs  

cyclins

What is the role of CdKs?

to signal the cell to move to the next phase of the cell cycle

Explanation:

As the frequency decreases the wavelength...

Answers

Answer:

Increase

Explanation:

Assuming a sinusoidal wave moving at a fixed wave speed, wavelength is inversely proportional to frequency of the wave: waves with higher frequencies have shorter wavelengths, and lower frequencies have longer wavelengths.


If you have 100 particles of hydrogen and 100 particles of oxygen, how many units of water can you form? Will you use all the particles of both
elements? If not, what will remain?

Answers

Answer:

82

Explanation:

i took the assingment

1. Which of these is not one of the main 6 forms of energy?
O a. Nuclear energy
O b. Chemical energy
O c. Light energy
O d. Electromagnetic energy

Answers

Answer:

Chemical energy

Explanation:

Chemical Energy

what is atomic?................................................

Answers

Answer:

oh I'm here thanks for your points

Answer:

thanx for the points

Explanation:

3. IDENTIFY the following reactions as Oxidation / Reduction reactions ?
a) PbO + H2 --> Pb + H2O
b) ZnO + C --> Zn + CO
c) H2S + Cl2--> 2HCl + S
d) Fe203 + 3C0 --> 2Fe + 3CO2
e) PbS + 4H202 --- PbSO4 + 4H2O​

Answers

a) Is reduction AND oxidation
[ Reduction: since there is a loss of oxygen in Pb]
[Oxidation: since there is a gain of oxygen in H2O]

b) Reduction AND oxidation
[Reduction: since there is a loss of oxygen in Zn]
[Oxidation: since there is gain of oxygen in CO]

c) Oxidisation AND reduction
[Oxidisation: since there is a loss of electrons in S]
[Reduction: since there is a gain of electrons in Cl^-1]

d)Reduction AND oxidation
[Reduction: since there is a loss of oxygen in 2Fe]
[Oxidation: since there is a gain of oxygen in 3CO2]

e) Oxidation AND Reduction
[Oxidation: since there is a gain of oxygen in PbSO4]
[Reduction: since there is a loss of oxygen in 4H2O]

( Hope this was helpful... And I apologize if any of the answers are incorrect.... I just did this chapter as well!)

Remember: Oxidation requires—Gain of O2
—Loss of H2
—Loss of elections

Reduction requires—loss of O2
—Gain of H2
—gain of electrons

Help pls!! Due in 30 mins!

Which equation represents a single replacement reaction?
1. 2Al(s) + 3Cl2(g) → 2AlCl3(s)

2. 2Al(s) + 6HCl(aq) + 2AlCl3(aq) + 3H2(g)

3. 2AlCl3(s) → 2Al(s) + Cl2(g)

4. AlCl3(aq) + 3KOH(aq) + Al(OH)3(s) + 3KCl(aq)

Answers

2. 2Al(s) + 6HCl(aq) + 2AlCl3(aq) + 3H2(g) represents a single replacement reaction

Further explanation

A single replacement reaction is a chemical reaction in which one element replaces the other elements of a compound to produce new elements and compounds

Not all of these reactions can occur. We can use the activity series(voltaic series), which is a list of elements that can replace other elements below / to the right of them in a single replacement reaction.

1. 2Al(s) + 3Cl2(g) → 2AlCl3(s)

Syntesis/combination reaction

2. 2Al(s) + 6HCl(aq) ⇒2AlCl3(aq) + 3H2(g)

Single replacement reaction

3. 2AlCl3(s) → 2Al(s) + Cl2(g)

Decomposition reaction

4. AlCl3(aq) + 3KOH(aq) + Al(OH)3(s) + 3KCl(aq)

Double  replacement reaction

In a single replacement reaction, one element replaces another one. The reaction that shows the single replacement reaction is:

[tex]\bold { 2Al(s) + 6HCl(aq) \rightarrow 2AlCl_3(aq) + 3H_2(g)}[/tex]

 

Single replacement reaction:It is a chemical reaction in which one element of the reactant compound replaces the other elements of another compound to form a new molecule.In these reactions, a more active element replaces the less active element.

[tex]\bold { 2Al(s) + 6HCl(aq) \rightarrow 2AlCl_3(aq) + 3H_2(g)}[/tex]

In the given reaction, aluminum replaces the hydrogen from hydrochloric acid to form Aluminum chloride.

Therefore, the reaction that shows the single replacement reaction is:

[tex]\bold { 2Al(s) + 6HCl(aq) \rightarrow 2AlCl_3(aq) + 3H_2(g)}[/tex]

Learn more about Single replacement reaction:

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For the water, what color is the hydrogen molecule?

Answers

Answer:

White is the color of a hydrogen molecule

Answer:

green. It is white when separate, but it turns green when it's formed into water.

Explanation:

Benzoic acid, C6H5COOH, is another derivative of benzene. The pH of an aqueous solution of benzoic acid at 298 K is 2.95. Determine the concentration of hydroxide ions in the solution,

Answers

Answer:

[OH⁻] = 8.91x10⁻¹²M

Explanation:

In aqueous solutions, the [OH] and [H⁺] are associated in the equation of hydrolisis of water:

1x10⁻¹⁴ = [OH⁻] [H⁺]

With pH, we can solve for [H⁺] and obtain, the [OH⁻] using this equation:

pH = -log [H⁺]

[H⁺]= 10^-pH

[H⁺] = 1.122x10⁻³M

1x10⁻¹⁴ = [OH⁻] [1.122x10⁻³M]

[OH⁻] = 8.91x10⁻¹²M

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