Which of the following is an example of a chemical change
A. apple slices turn brown
B. toast burns
C. silver tarnishes
D. all of these are chernical changes​

Answers

Answer 1

Answer:

D. all of these are chemical changes


Related Questions

explain why division by zero is undefined​

Answers

Answer:

Division by zero is undefined because there is no other number to divide it by.

Explanation:

Unlike 2/2, 2/0 doesn't have anything to divide the 2 by which makes it undefined and impossible to solve.

The division by zero is undefined​, because whatever response we may give, we will then have to concur that the answer times 0 = 1, which is illogical because anything multiplied by zero is zero.

Why division by zero is undefined​ ?

Since any attempt at definition results in a contradiction, the outcome of a division by zero cannot be defined. a=r*b. r*0=a. (1) (1) But because r*0=0 for all r, there is no solution to the equation unless a=0 (1).

Again, mathematicians have left zero divided by zero as an open problem because they are both equally valid and, to be honest, neither of them is consistent with the rest of mathematics.

Mathematically, it is impossible to divide a number by zero, just as in this illustration. Or, at the very least, there isn't currently a means to do that. Numerous attempts have been made to figure out how to divide by zero, as mathematicians are constantly looking for solutions to intriguing mathematical issues.

Thus, The division by zero is undefined​, because whatever response we may give, we will then have to concur that the answer times 0 = 1.

To learn more about division by zero is undefined, follow the link;

https://brainly.com/question/11523699

#SPJ2

Decaying plants and animals are important to an ecosystem because they
A.
cause disease in living organisms.
B.
reduce soil erosion.
C.
recycle oxygen to the air.
D.
return nutrients to the soil.

Answers

Answer:

The option D is correct answer.

Decaying pants and animals are important to the ecosystem as they return the nutrients to the soil.

What is an ecosystem?

Ecosystem is defined as a system which consists of all living organisms  and the physical components with which the living beings interact. The abiotic and biotic components are linked to each other through nutrient cycles  and flow of energy.

Energy enters the system through the process of photosynthesis .Animals play an important role in transfer of energy as they feed on each other.As a result of this transfer of matter and energy takes place through the system .Living organisms also influence the quantity of biomass present.By decomposition of dead plants and animals by microbes nutrients are released back in to the soil.

Learn more about ecosystem,here:

https://brainly.com/question/19267717

#SPJ2

When measuring solid NaOH in pellet form, explain why you won’t be able to measure exactly 1.000 grams. What are the consequences of this?

Answers

Answer:

Explanation:

Pellet form of NaOH is highly hygroscopic . It absorbs moisture from air and its weight is increased by the time one tries to weigh one gram of it . Moreover it also reacts with carbon dioxide gas of atmosphere to form sodium carbonate .

2 NaOH + CO₂ = Na₂CO₃ + H₂0.

It also increases its weight .

In which of does the convection only occur in

A. Gases
B. Fluids
C. Liquids
D. Solids

Answers

Answer:

B. Fluids

I hope this helps!

Answer:

B

Explanation:

find the R when p=6000,T=3 yrs 6 month ,I=1155​

Answers

Answer:770R=I×100/P×T

R= 1155×100/6000×3/12

R= 1155×2/3

R=770

1
Select the correct answer.
Which statement about the relationship between laws, hypotheses, and theories is true?

A.
Laws that remain true over an extended period of time are considered theories.
B.
A theory that holds true for a long time is considered a law.
C.
If a law is not contradicted after a lot of testing, it may be considered a hypothesis.
D.
If a hypothesis is not contradicted after a lot of testing, it may be considered a law.

Answers

Answer:

the answer is D

Explanation:

If ΔH vaporization of water (H2O) is 40.7 kJ/mol,
and the ΔS for vaporization of H2O is 109 J/mol K,
what is ΔG for water vaporization at 350K?
Include units.

Answers

Answer:

2.6 kJ/mol

Explanation:

Step 1: Given data

Standard enthalpy of vaporization of water (ΔH°): 40.7 kJ/molStandard entropy of vaporization of water (ΔS°): 109 J/mol.KAbsolute temperature (T): 350 KStandard Gibbs free energy of vaporization of water (ΔG°): ?

Step 2: Calculate ΔG°

We can calculate ΔG° using the following expression.

ΔG° = ΔH° - T × ΔS°

ΔG° = 40.7 kJ/mol - 350 K × 0.109 kJ/mol.K

ΔG° = 2.6 kJ/mol

The change in Gibbs free energy, ΔG for the water is 2.55 KJ/mol

Data obtained from the question

From the question given above, the following data were obtained:

Standard enthalpy of vaporization of water (ΔH°) = 40.7 kJ/molStandard entropy of vaporization of water (ΔS°) = 109 J/Kmol = 109 / 1000 = 0.109 KJ/Kmol Absolute temperature (T) = 350 KStandard Gibbs free energy (ΔG°) =?

How to determine the Gibbs free energy, ΔG°

The Gibbs free energy, ΔG° can be obtained as illustrated below:

ΔG° = ΔH° – TΔS°

ΔG° = 40.7 – (350 × 0.109)

ΔG° = 40.7 – 38.15

ΔG° = 2.55 KJ/mol

Learn more about Gibbs free energy:

https://brainly.com/question/9256736

chemical test of acetylene in the laboratory​

Answers

Using tweezers a calcium carbide granule is dropped in the water in the container and bubbles of acetylene gas begin to be produced. A test tube full of water is inverted and placed over the evolving gas. The gas displaces the water and the entire test tube fills with acetylene.
Hope that helps

1- Science that deals with the identification and quantification of the components of material systems
A)Analytical Science
B)Biochemistry
C)Organic Chemistry
D) Inorganic Chemistry
Q1-(30 Marks) Choose the correct answer​

Answers

Answer:

Analytical science

Explanation:

What is the mass, in grams, of the ethyl alcohol that exactly fills a 220 mL container? The density of ethyl alcohol is 0.789 g/mL. Group of answer choices 170 g 173.58 g 280 g 278.833967 g

Answers

Answer:

[tex]m=173.58g[/tex]

Explanation:

Hello,

In this case, since the density is the ratio of the mass and volume:

[tex]\rho =\frac{m}{V}[/tex]

For the given density and volume, the correct mass which fills the given volume is:

[tex]m=\rho *V=0.789g/mL*220mL\\\\m=173.58g[/tex]

Best regards.

What is the volume of a sample of matter with a density of 6 and a mass of 6 cm3?

Answers

Answer:

We have the final answer as

1.0 cm³

Explanation:

The volume of a substance when given the density and mass can be found by using the formula

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

From the question

mass = 6 g

density = 6 g/cm³

It's volume is

[tex]volume = \frac{6}{6} = 1 \\ [/tex]

We have the final answer as

1.0 cm³

Hope this helps you

How many grams are there in 1.00x10 24 molecules of BCI3

Answers

Answer:

194.569 g

Explanation:

6.022×10^23 molecules = 117.17 g

1 molecules = 117.17/ 6.022×10^23

So, 1×10^24 molecules = (117.17×1×10^24)/(6.022×10^23)= 194.569 g

a nucleus with 4 protons has a positive charge of _____ PLEASE LET ME KNOW

Answers

Answer:

if were talking about berylium then the answer should be 2 because it wants to move 2 spaces back (losing electrons) to become a nobel gas so the answer is 2+

Explanation:

it has 2 valence electrons YW :)    

A nucleus with 4 protons has a positive charge of +2.

What are Protons?

Protons may be defined as the type of sub-atomic particles that are present in the nucleus of an atom along with the neutrons. These sub-atomic particles possess a positive charge in nature. It may be thought that protons are discovered by Ernest Rutherford.

Beryllium has a nucleus with 4 protons, which means that it has an atomic number of 4. This element belongs to the alkaline earth metals in group 2. Beryllium has the capability to lose two electrons in order to attain a noble gas configuration and occupy stability. It has an electronic configuration [tex]1s^2, 2s^2[/tex]. So, in order to make it octet fulfilled, it loses two electrons and becomes positively charged.

Therefore, a nucleus with 4 protons has a positive charge of +2.

To learn more about Protons, refer to the link:

https://brainly.com/question/1805828

#SPJ2

Which of the following is considered an ionic solid? a) (NH4)2CO3 b) CBr4 c) SeBr2 d) XeF4 e) None of the above is an ionic solid.

Answers

Answer: NH4)2CO3

Explanation:

Ionic solids are the solids that are simply held together by ionic bonds. Ionic bonds are lattices that are typically made up of oppositely charged ions and they usually possess a high melting point.

An example of ionic bond is NH₄)₂CO₃ which is referred to as Ammonium carbonate. This is a salt and it readily degrades upon heating to carbon dioxide and gaseous ammonia.

PLEASE HELP ME, I HAVE NO IDEA HOW TO DO THIS :(

Answers

Lol . same here. If u get any ideas please let me know

Answer:

See the picture you have to write like this

3. Calculate each of the following:
a) kg of 4.6x1021 molecules of nitrogen dioxide
b) moles of chlorine atoms in 0.615 g of C2H4Cl2
c) number of hydride ions in 5.82 g of strontium hydride

Answers

Answer:

the answers are at the very bottom of each picture

Explanation:

i really hope this helps you:)

Oxalic acid, H2C2O4*2H2O (molar mass = 126.07 g/mol) is oftenused as a primary standard for the standardization of a NaOHsolution. If 0.147 g of oxalic acid dihydrate is nutralizedby 23.64mL of a NaOH solution, what is the molar concentration ofthe NAOH solution? Oxalic acid is a diprotic acid. (What is thebalanced equation?)

Answers

Answer:

0.09865M of NaOH

Explanation:

As a diprotic acid, 1 mole of oxalic acid reacts with 2 moles of NaOH as follows:

H2C2O4 + 2 NaOH → 2 H2O + Na2C2O4

With the mass of the acid and its molar mass we can obtain the moles of oxalic acid. Twice these moles are the moles of NaOH in the solution. As you required 23.64mL = 0.02364L of the NaOH, you can knkow molarity, thus:

Moles Oxalic acid:

0.147g * (1mol / 126.07g) = 1.166x10⁻³ moles Oxalic acid.

Moles NaOH:

1.166x10⁻³ moles Oxalic acid * (2 moles NaOH / 1 mole H2C2O4) = 2.332x10⁻³ moles NaOH

Molarity:

2.332x10⁻³ moles NaOH / 0.02364L =

0.09865M of NaOH

Over the course of many years, a rural farm town becomes more urban. Which of the following will most likely happen in the town as a result of this urbanization?

Answers

Answer:

Explanation:

Rivers may be contaminated by sewage.

I do hope I helped you! :)

3 points
What is the energy (Joules) of violet light with a frequency = 3.43 x 10^14
1/s? *
4.54x10^-19 J
1.99x10^-25 J
1.93 x 10^-48 J
O 2.27 x 10^-19 J
Pls help me

Answers

Answer:

4.54x10^-19 J

1.99x10^-25 J

1.93 x 10^-48 J

In a compound the elements are _____ together, whereas in a mixture the substances are blended together.

Answers

Answer:

bonded

Explanation:

Compounds are two elements bonded together.

A mixture is multiple substances blended together.  The substances aren't bonded together and can easily be extracted  from each other.

The flask contains 10.0 mL of HCl and a few drops of phenolphthalein indicator. The buret contains 0.160 M NaOH. It requires 18.2 mL of the NaOH solution to reach the end point of the titration. A buret filled with a titrant is held above a graduated cylinder containing an analyte solution. What is the initial concentration of HCl

Answers

Answer:

Approximately [tex]0.291\; \rm M[/tex] (rounded to two significant figures.)

Explanation:

The unit of concentration [tex]\rm M[/tex] is the same as [tex]\rm mol \cdot L^{-1}[/tex] (moles per liter.) On the other hand, the volume of both the [tex]\rm NaOH[/tex] solution and the original [tex]\rm HCl[/tex] solution here are in milliliters. Convert these two volumes to liters:

[tex]V(\mathrm{NaOH}) = 18.2\; \rm mL = 18.2 \times 10^{-3}\; \rm L = 0.0182\; \rm L[/tex].[tex]V(\text{$\mathrm{HCl}$, original}) = 10.0\; \rm mL = 10.0\times 10^{-3}\; \rm L = 0.0100\; \rm L[/tex].

Calculate the number of moles of [tex]\rm NaOH[/tex] in that [tex]0.0182\; \rm L[/tex] of [tex]0.160\; \rm M[/tex] solution:

[tex]\begin{aligned} n(\mathrm{NaOH}) &= c(\mathrm{NaOH})\cdot V(\mathrm{NaOH})\\ &= 0.160\; \rm mol \cdot L^{-1} \times 0.0182\; \rm L \approx 0.00291\; \rm mol\end{aligned}[/tex].

[tex]\rm HCl[/tex] reacts with [tex]\rm NaOH[/tex] at a one-to-one ratio:

[tex]\rm HCl\; (aq) + NaOH\; (aq) \to NaCl\; (aq) + H_2O\; (l)[/tex].

Coefficient ratio:

[tex]\displaystyle \frac{n(\mathrm{HCl})}{n(\mathrm{NaOH})} = 1[/tex].

In other words, one mole of [tex]\rm NaOH[/tex] would neutralize exactly one mole of [tex]\rm HCl[/tex]. In this titration, [tex]0.291\; \rm mol[/tex] of [tex]\rm NaOH\![/tex] was required. Therefore, the same amount of [tex]\rm HC[/tex] should be present in the original solution:

[tex]\begin{aligned}&n(\text{$\mathrm{HCl}$, original})\\ &= n(\mathrm{NaOH})\cdot \frac{n(\mathrm{HCl})}{n(\mathrm{NaOH})} \\ &\approx 0.00291\; \rm mol \times 1 = 0.00291\; \rm mol\end{aligned}[/tex].

Calculate the concentration of the original [tex]\rm HCl[/tex] solution:

[tex]\displaystyle c(\text{$\mathrm{HCl}$, original}) = \frac{n(\text{$\mathrm{HCl}$, original})}{V(\text{$\mathrm{HCl}$, original})} \approx \frac{0.00291\; \rm mol}{0.0100\; \rm L} \approx 0.291\; \rm M[/tex].

Be sure to answer all parts. Calculate the mass of each product formed when 70.76 g of diborane (B2H6) reacts with excess water: B2H6(g) + H2O(l) → H3BO3(s) + H2(g) [unbalanced] Mass of H3BO3: g Mass of H2: g

Answers

Answer:

A. 313.37 g of H3BO3.

B. 30.33 g of H2.

Explanation:

We'll begin by writing a balanced equation for the reaction. This is given below:

B2H6 + 6H2O → 2H3BO3 + 6H2

Next, we shall determine the mass of B2H6 that reacted and the masses of H3BO3 and H2 produced from the balanced equation equation. This can be obtained as follow:

Molar mass of B2H6 = (2×11) + (1×6) = 22 + 6 = 28 g/mol

Mass of B2H6 from the balanced equation = 1 × 28 = 28 g

Molar mass of H3BO3 = (1×3) + 11 + (3×16) = 3 + 11 + 48 = 62 g/mol

Mass of H3BO3 from the balanced equation = 2 × 62 = 124 g

Molar mass of H2 = 2×1 = 2 g/mol

Mass of H2 from the balanced equation = 6 × 2 = 12 g

From the balanced equation above:

28 g of B2H6 reacted to produce 124 g of H3BO3 and 12 g of H2.

A. Determination of the mass of H3BO3 produced from the reaction.

This can be obtained as follow:

From the balanced equation above,

28 g of B2H6 reacted to produce 124 g of H3BO3.

Therefore, 70.76 g of B2H6 will react to produce = (70.76 × 124)/28 = 313.37 g of H3BO3.

Therefore, 313.37 g of H3BO3 were obtained from the reaction.

B. Determination of the mass of H2 produced from the reaction.

This can be obtained as follow:

From the balanced equation above,

28 g of B2H6 reacted to produce 12 g of H2.

Therefore, 70.76 g of B2H6 will react to produce = ((70.76 × 12)/28 = 30.33 g of H2.

Therefore, 30.33 g of H2 were obtained from the reaction.

can some one help The function of the cell wall in a plant cell is Question 2 options: Allowing material to pass in and out of the cell Uses carbon dioxide, water and energy from the sun to make sugar Breaks sugar down into ATP which the cell can use for energy Provides support and protection for the cell

Answers

Answer:

the protection one

Explanation:

the cell wall acts a barrier

E
1
1 point
Which of the following is an elemental substance?
Select all the correct answers.
Mercury
2
Oxygen (O2)
3
Platinum
Chlorine (C12)
Carbon Dioxide (CO2)

Answers

Answer:

oxygen and Carbon dioxide

A pure copper penny contains approximately 2.9×1022 copper atoms. Use the following definitions to determine how many ______ of copper atoms are in a penny. 1doz=12 1gross=144 1ream=500 1mol=6.022×1023 Part A dozens Express your answer in dozens to two significant figures.

Answers

Complete question is;

A pure copper penny contains approximately 2.9 × 10^(22) copper atoms.

1 doz = 12

1 gross = 144

1 ream = 500

1 mol = 6.022 × 10^(23)

Use these definitions to determine the following:

A) How many dozens of copper atoms are in a penny.

B) How many gross of copper atoms are in a penny

C) How many reams of copper atoms are in a penny.

D) how many moles of copper atoms are in a penny?

All answers can be rounded to two significant figures

Answer:

A) 2.4 × 10^(21) dozens

B) 2.01 × 10^(20) gross

C) 5.8 × 10^(19) reams

D) 0.048 mol

Explanation:

A) A dozen contains 12.

Therefore, 2.9 × 10^(22) copper atoms will contain;

(2.9 × 10^(22))/12 dozens = 2.42 × 10^(21).

In 2 significant figures, we have;

2.4 × 10^(21) dozens

B) 1 gross = 144

Therefore, 2.9 × 10^(22) copper atoms will contain;

(2.9 × 10^(22))/144 gross ≈ 2.01 × 10^(20) gross

C) 1 ream = 500

Therefore, 2.9 × 10^(22) copper atoms will contain;

(2.9 × 10^(22))/500 reams = 5.8 × 10^(19) reams

D) 1 mol = 6.022 × 10^(23)

Therefore, 2.9 × 10^(22) copper atoms will contain;

(2.9 × 10^(22))/(6.022 × 10^(23)) = 0.048 mol

You bought a new car and estimated that your monthly payment would be $312. However, your actual payment amount is $325. How much error was in your estimate?

Answers

There was a $13 difference

Which of the following is a buffer system?
A. NaCl and NaNO3
B. H2CO3 and KHCO3
C. HCl and NaOH
D. H2O and HCl
E. NaCl and NaOH

Answers

Answer:

B. H2CO3 and KHCO3

Explanation:

The buffer system is a system in which the solution deny for change in the ph level i.e. at the time when the acid is added to it. It can be made either in a weak acid and salt or can be a weak base and its salt. Now when the acid is added to a buffer so the ratio is not impacted due to which it does not change sufficient for pH level

As per the given options, the third one is correct as the H2CO3 denotes a weak acid and the KHCO3 represents the salt. And these two solution does not create any change in the level of pH

Therefore the option B is correct

Part Of flowers that contains pollen is


Please answer right

Answers

Answer:

its the stamen, it also supports the Anther.

Answer:

The Stamen

Explanation:

The stamen is a slender filament supporting the anther, it is what produces and holds pollen in flowers.

how many atoms are in 2 miles of h2o

Answers

Answer:

one mole of water contains 6.02 x 1023 MOLECULES of water.

But each molecule of water contains 2 H and 1 O atom = 3 atoms, so there are approximately 1.8 x 1024 atoms in a mole of water.

Explanation:

hope it helps you paigegeorge

A state of dynamic equilibrium, Ag2CO3(s) 2Ag^+(aq) + CO3^2-, exists in solution.
What shift occurs in the equilibrium if HCl (aq) is added to the system? Explain please

Answers

Answer:

The equilibrium will shift to the right producing more Ag⁺ and CO₃²⁻

Explanation:

In the equilibrium:

Ag₂CO₃(s) ⇄ 2Ag⁺(aq) + CO₃²⁻(aq)

The change in concentration of Ag⁺ or CO₃²⁻ will shift the equilibrium

The addition of HCl(aq) (Dissociates in H⁺ and Cl⁻ ions) produce the formation of AgCl. The reaction is:

Ag⁺(aq) + Cl⁻(aq) ⇄ AgCl(s)

That means the addition of HCl decrease concentration of Ag⁺.

Based on LeChatelier's principle: As the Ag⁺ decreases, the equilibrium will decrease amount of Ag₂CO₃ producing more Ag⁺ and CO₃²⁻. That is:

The equilibrium will shift to the right producing more Ag⁺ and CO₃²⁻
Other Questions
A car reversing at -7.2 m/s has a displacement of -21.6 m. How long did this take? Lola bought 9 pounds of apples for $15.75What is the price per pound for the apples she bought NEED HELP ASAP WILL GIVE BRAINLY AWARD A company produces 4.56 times 10 Superscript 3 light bulbs each week. Written in scientific notation, which is the best estimate of how many light bulbs the company will make in 9.36 times 10 Superscript 2 weeks?4.5 times 10 Superscript 1 light bulbs1.4 times 10 Superscript 5 light bulbs4.5 times 10 Superscript 6 light bulbs45 times 10 Superscript 6 light bulbs When a salesperson asks for the sale, he or she is trying to:_________. a recipe for one batch of cookies calls for 5 cups of flour and 2 teaspoons of vanilla.how many batches can you make with 15 cups of flour and 6 teaspoons of vanilla? Jamie has 175 in her savings account every year 75 is added to her account tanner has 50 in his savings account every year 100 is added to his account and how many do you have a what do i have in common with a tree? I cant figure out___left the note on my desk Who Whom Qu es lo ms divertido del mundo de acuerdo a la historia? I need help to make it positive PLEASE HELP THIS IS THE LAST QUESTION AND I WANT TO GO TO BED. PLEASE EXPLAIN SO I CAN DO IT FOR NEXT TIME AS WELL An_____transaction involves an exchange between the company and a separate economic entity. How did the emperor constantine help the spread of christianity 47.469 rounded to the nearest foot PLEASE HELP MEFactor the common factor out of each expression 2) 7b + 28b Researchers randomly divide participants into groups. Each group takes a different amount of omega-3 fatty acid supplements daily for a month. One group receives a placebo. The researchers measure the impact on cholesterol levels in the blood. What is the purpose of random assignment in this experiment a deer stands cast a shadow 15 feet long at the same time that a 4-foot-tall casts a shadow that is 6feet long. how tall is the deer stand 2x-2 ??????????????????????????????????????????????????? An angle measuring 3.6 radians is drawn in standard position?In what quadrant will the terminal side of this angle lie?Express your answer as a Roman numeral.