A student in a lab holds an iron nail over an open flame, and no reaction occurs. The nail is then filed, creating small pieces of iron shavings. These pieces burn brightly when placed over an open flame.

Which statement accurately identifies one of the changes that occurs as a physical or chemical change?

A. Filing the nail is a chemical change because the composition of the material does not change but the general appearance of the iron does change.

B. Burning the iron filings is a chemical change because the composition of the material does not change but the general appearance of the iron does change.


C. Filing the nail is a physical change because the composition of the material does not change but the general appearance of the iron does change.


D. Burning the iron filings is a physical change because the composition of the material does not change but the general appearance of the iron does change.

Answers

Answer 1

Answer:

A - Filing the nail is a physical change because the composition of the material does not change but the general appearance of the iron does change.

Explanation

yeah its just the right answer

Answer 2

The following statement accurately identifies one of the changes that occurs as a physical or chemical change;  "Filing the nail is a physical change because the composition of the material does not change but the general appearance of the iron does change."

The most important aspect of chemical change is that  the composition of a substance changes when the substance undergoes a chemical change. This is not the case when the substance undergoes a physical change.

After a physical change, the form, size or appearance may change but never in composition.

Hence the appropriate answer is;  "Filing the nail is a physical change because the composition of the material does not change but the general appearance of the iron does change."

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Related Questions

Into what genre does a novel fit that
takes place in a made-up world and
has events that couldn't really
happen?
A. non-fiction
B. mystery
C. fantasy

Answers

Answer:

A. non fiction or a ajami to download

Part A
In the year 2012, an estimated amount of 31.6 billion metric tons (1 metric ton = 1000 kg) of carbon dioxide (CO2) was emitted worldwide due to fossil fuel combustion
and cement production. Express this mass of CO2 in grams without exponential notation, using an appropriate metric prefix

Answers

The mass of CO₂ in grams without exponential notation and with the appropriate metric prefix is 31.6 Eg.  

First, let's calculate the amount of mass in grams of 31.6 billion metric tons.

Knowing that 1 metric ton is equal to 1000 kg, 31.6 billion metric tons is:

[tex]m = \frac{1000 kg}{1 \: metric \: ton}*\frac{1000 g}{1 kg}*31.6 \cdot 10^{12} \: metric \: ton = 3.16 \cdot 10^{19} g[/tex]              

The metric prefix that is close to the above result is exa (E), which is equal to 10¹⁸.

Therefore, the mass of CO₂ in grams without exponential notation and with the appropriate metric prefix is 31.6 Eg (exa-gram).  

To learn more about metric prefixes go here: https://brainly.com/question/20712978?referrer=searchResults

I hope it helps you!

lidocain có tính bazơ không

Answers

Answer:

Lidocain là cơ bản.

Tôi hy vọng câu trả lời của tôi là hữu ích cho bạn.

CHAPTER 8 FORCE AND MOTION

Choose the S.I. unit for pressure.

1. Watt
2. Joule
3. Pascal
4.Newton

Answers

SI unit for pressure is Pascal

Please help me out in this question am giving the brainliest

Answers

concentration of NaOH = moles of NaOH/total volume of solution

moles of NaOH = mass/Mr = 120g/(23+16+1) = 3moles

concentration of NaOH = 3moles/2L =1.5M

how to find the average speed of something

Answers

Answer:

if you want to find average speed so u need to use this formula

Average speed = [tex]\frac{Total Displacement}{Total Time}[/tex]

Which formula can be used to calculate the percent yield?
a.(Theoretical yield ÷ actual yield) x 100
b.(Actual yield ÷ theoretical yield) x 100
c.(Amount of reactants ÷ amount of products) x 100
d.(Amount of products ÷ amount of reactants) x 100

Answers

The answer to this question is the second one (B)
B is the correct answer

A sealed reaction vessel initially contains 1.113×10-2 moles of water vapor and 1.490×10-2 moles of CO(g).

H20(g) +CO(g) <==> H2(g) + CO2(g)

After the above reaction has come to equilibrium, the vessel contains 8.326×10-3 moles of CO2(g).

What is the value of the equilibrium constant Kc of the reaction at the temperature of the vessel?

Answers

Answer:

Kc =[tex]\frac{[8.326x10-3]^{1} }{[1.113x10-2]^{1}[1.490x10-2]^{1} }[/tex]

Kc = 50.2059

Explanation:

1. Balance the equation

2. Use the Kc formula

Remember that pure substances, like H2 are not included on the Kc formula

The value of the equilibrium constant Kc of the reaction at the temperature of the vessel is 0.05.

Calculation,

The balanced chemical equation is given as,

                      [tex]2H_{2}O[/tex]             +         [tex]2CO[/tex]            →            [tex]2H_{2}[/tex]       +     [tex]2CO_{2}[/tex]

At t=0          1.113×[tex]10^{-2}[/tex]                 1.490×[tex]10^{-2}[/tex]                                         0

At [tex]t=t_{eq}[/tex] 1.113×[tex]10^{-2}[/tex]-8.326×[tex]10^{-3}[/tex]   1.490×[tex]10^{-2}[/tex]-8.326×[tex]10^{-3}[/tex]            8.326×[tex]10^{-3}[/tex]  

The number of moles of [tex]H_{2}O[/tex] at equilibrium  =  1.113×[tex]10^{-2}[/tex]-8.326×[tex]10^{-3}[/tex]

The number of moles of [tex]CO[/tex] at equilibrium  = 1.490×[tex]10^{-2}[/tex]-8.326×[tex]10^{-3}[/tex]

The number of moles of  [tex]CO_{2}[/tex]   at equilibrium =   8.326×[tex]10^{-3}[/tex]  

What is equilibrium constant?

Equilibrium constant is calculated bt ratio of product of concentration of reactant by product.

K = [tex][H_{2}O]^{2}[/tex]×[tex][CO]^{2}[/tex]/[tex][CO_{2}]^{2}[/tex]

K =( 1.113×[tex]10^{-2}[/tex]-8.326×[tex]10^{-3}[/tex] )∧2× (1.490×[tex]10^{-2}[/tex]-8.326×[tex]10^{-3}[/tex])∧2/(8.326×[tex]10^{-3}[/tex])∧2

K = 0.049 ≈ 0.05

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Which benzene derivative would be the least reactive in an electrophilic aromatic substitution reaction

Answers

benzene with electron withdrawing group as a substituent will be least reactive in an electrophilic aromatic substitution

example of electron withdrawing group are: NO2, carbonyls

Choose the best possible answer for Q.No. A, B, and C.

The following is an acid-base reaction between sulfuric acid and aluminum hydroxide. Use the provided molar masses to answer the questions below:

molar

mass

3 H2SO4

+

2 Al(OH)3



Al2(SO4)3

+

6 H2O

g/mol

98.08



78.00



342.15



18.02

Note: You need to upload the documents for A, B, and C to show your work.



A. How many moles of sulfuric acid would be required to form 65.21g of Water?

moles of H2SO4 = ________
[ Select ]



B. How many grams of Aluminum Sulfate could be formed if 197.0g aluminum hydroxide reacts with sulfuric acid?

mass of Al2(SO4)3 = ________
[ Select ]



C. To determine the concentration of a sulfuric acid sample, a titration is performed with the above reaction. What is the concentration of the sulfuric acid if a 15.00mL sample reached its titration endpoint with 29.26mL of 0.2855M Al(OH)3?

Molarity of H2SO4 = ________
[ Select ]

Answers

Answer:

c i think

Explanation:

Who developed the gas law that relates pressure and temperature?

Answers

Explanation:

physicist Robert Boyle

Answer: Boyle

Explanation: Educere Answer

What is the correct clases for this drugs

‏Compazine
heelp me please
and
Promethazine

Answers

Answer:

Compazine belongs to a class of drugs called Antiemetic Agents; Antipsychotics, Phenothiazine.

A lab team places 0.250g of an unknown solid acid in an Erlenmeyer flask. They neutralize the solid acid with 15.0ml of 0.210 M Na(OH)(aq). One mole of the acid reacts with one mole of the base. Calculate the molar mass of the unknown solid acid O 158 g/mol 0 7.9 g/mol 79.4 g/mol 0 763 g/mol​

Answers

Answer:

Molar mass of the unknown acid is 79 grams

Explanation:

We have to first get moles in 15.0 ml of sodium hydroxide solution:

[tex]{ \sf{1 \: l \: of \:NaOH \: contains \: 0.210 \: moles }} \\ { \sf{0.015 \: l \: of \: NaOH \: contain \: (0.015 \times 0.210) \: moles }} \\ { \underline{ = 0.00315 \: moles \: of \: NaOH}}[/tex]

since mole ratio of acid : base is 1 : 1, so;

moles of acid that reacted is 0.00315 moles of the unknown acid.

then we've to get molar mass:

[tex]{ \sf{0.00315 \: moles \: of \: acid \: weigh \: 0.250 \: g}} \\ { \sf{1 \: mole \: of \: acid \: weighs \: ( \frac{1 \times 0.250}{0.00315} ) \: g}} \\ { \underline{ = 79.4 \: g \approx79 \: grams}}[/tex]

will it sink or float?
giving brainlist

Answers

Answer:

Air will Float

Ice will Float.

aluminium will sink

Lead. has to sink

Gold will sink

Ethanol it will nor sink or float. it is like neutral.

methanol will Float.

Explanation:

may it helps you.

Mark me brainlist if it helps you

Question 18(Multiple Choice Worth 5 points)
(03.02 MC)
Which of the following elements has properties different than the rest?
H
K
N
O

Answers

Answer:

H

hydrogen have different properties

Identify whether the solubility of Ag_2CrO_4 will increase or decrease by adding the following agents.

a. Na2CrO4
b. HCl
c. NH3

Answers

a) with addition of Na2CrO4 the solubility of silver chromate will be reduced as there are more chromate ions in the solution which are coming from sodium chromate
b) with addition of HCl silver chromate solubility will increase as silver chromate reacts with HCl to produce silver chloride precipitate (white). silver chromate is red-brown color hence it can be easily distinguished
c) with NH3 silver chromate will form diamine complex and results in increased solubility of silver chromate

3-4. When something interests you, how do you make a hypothesis?
5-6. Why is it important to take a good notes when you are conducting an experiment?
7-8. What is the last step in the scientific method? Explain.
9-10. Name one thing you want to investigate this year for a scientific project? Why? ​

Answers

Answer:

3-4. I think we should research the topic, and make a assumption based on what you learned.

5-6.There are times when a scientist is unable to answer his own question. If he has taken good notes, another scientist may come along later and use his notes to find the answer. Every year there is new knowledge. The scientific method is a step-by-step process.

7-8.The final step of the scientific process is to report your results. Scientists generally report their results in scientific journals, where each report has been checked over and verified by other scientists in a process called peer review.

9-10. I don't know this one.

1. A substance with 1 or 2 electrons in the valence shell is called what?

A. Insulator

B. Conductor

C. Molecule

D. Semiconductor

Answers

Answer:

B. Conductor

Explanation:

The density of Silver is 10.5 g/mL. How much mass would be present given a silver cube
with a volume of 25.0 mL?


PLEASE HELP ASAP

Answers

Answer:

m=dxv

= 10.5 x 965 = 10132.5 rounded off to 10100 g

Explanation:

Selenium, an element required nutritionally in trace quantities, forms compounds analogous to sulfur. Name the following ions.

a. SeO_4^2-
b. Se^2-
c. HSe^-
d. HSeO_3^-.

Answers

a. selenate . (sulfate counterpart)
b. selenide . (sulfide counterart)
c. hydroselenide . (hydrosulfide counterpart)
d. hydrogen selenite

The names of ion are:

[tex]Selenate = SeO_4^{2-}\\Selenide = Se^{-2}\\Hydroselenide = HSe^-\\Hydrogenselenite = HSeO_3^-\\[/tex]

Explanation:

Sulfur forms various compounds such as sulfates, sulfites,  sulfides, hydrosulfides, hydrogensulfites.The  symbols of these ions are:

[tex]Sulfate = SO_4^{2-}\\Sulfite = SO_3^{2-}\\Sulfide = S^{-2}\\Hydrosulfide = HS^-\\Hydrogensulfite = HSO_3^-\\[/tex]

According to the question, selenium also forms compounds analogous to sulfur so the name of the given ions of selenium will be in analogy to that of the sulfur compound.

[tex]Selenate = SeO_4^{2-}\\Selenide = Se^{-2}\\Hydroselenide = HSe^-\\Hydrogenselenite = HSeO_3^-\\[/tex]

Learn more about sulfur and selenium here

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what is the density of a 5 mL sample of 1.95g of Gold

Answers

Answer:

density=mass/volume

=1.95/5 = 0.39 g(mL)-¹

The body of knowledge that deals with Earth and its place in the universe is called _____________?

Answers

Answer:

Cosmology is a branch of astronomy that involves the origin and evolution of the universe, from the Big Bang to today and on into the future. According to NASA, the definition of cosmology is "the scientific study of the large scale properties of the universe as a whole."

Write differences between reactants and products.​

Answers

Reactants - The substance which participate in a chemical reaction are called reactants.

[tex] \rm \: Example - H_2 \: , \: O_2[/tex]

Product - The substance which are formed by chemical reaction between the reactants are called product.

[tex]\rm \: Example - H_2 O[/tex]

Explanation:

reactant is a substance that is present at

the start of a chemical reaction.

product is a substance

that is present at the end of a chemical

reaction.

Metric system is also known as the (use the amount of letters in 16 across) WILL MARK BRAINLIEST:))

Answers

Answer:

Si System

hope this helped!

How are electrons arranged around an atom?

Answers

Answer:

Viewed simply, electrons are arranged in shells around an atom's nucleus. Electrons closest to the nucleus will have the lowest energy. Electrons further away from the nucleus will have higher energy.

Answer:

Electrons are placed in the lower energy level first and when this is completely filled, we move on to the second energy level and so on. The way the electrons are arranged in an atom is called the atom's electronic structure or electronic configuration. The maximum number of electrons that the first shell can contain is 2.

Explanation:

when two atoms share four valence electrons the shared electrons form a/an ____

Answers

double bonds

2 electrons from each atoms

Water is placed into a sealed jar and has a mass of 22.0 grams. The jar is placed in the freezer and the water turns to ice. The jar of ice is measured. The mass should be:

a. Slightly less than 22.0 grams
b. Exactly 22.0 grams
c. Slightly more than 22.0 grams

Answers

exactly 22.0 grams

because freezing is a physical change not a chemicl change..so nothing is taken away or added

ANSWER;

exactly 22.0 grams

because freezing is a physical change not a chemicl change..so nothing is taken away or added

PLEASE HELP!!!!!!!!! WILL MARK BRAINLIEST

Answers

Answer:

19.278049929737628457607385688801

Explanation:

Volume = L * W * H

Volume = 17.78 * 9.21 * 4.45 = 728.70441

Density = Mass / Volume

Mass = 14,048

14,048 / 728.70441 = 19.278049929737628457607385688801

Density = 19.278049929737628457607385688801

Explanation:

So density = mass/volume

Using this formula we'll solve the question.

mass = 14,048g/1000 = 14.048 kg

volume = 17.78/100 x 9.21/100 x 4.45/100

volume = 0.3143 m³

density = 14.048 kg/ 0.3143 m³

density = 44.69 kg/m³

round off to = 44.7 kg/m³

When a liquid is at its boiling point, the vapor pressure of the liquid

Answers

When the liquid is at its boiling point the vapor pressure of the liquid increases

Which direction does heat flow from

Answers

And unless people interfere, thermal energy — or heat — naturally flows in one direction only: from hot toward cold. Heat moves naturally by any of three means. The processes are known as conduction, convection and radiation. Sometimes more than one may occur at the same time

Answer:

A

Explanation:

hot to cold; jus took the quiz;)

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