Chapter 3 PHYSICAL & CHEMICAL CHANGES by dwi pujiastuti

PHSICAL & CHEMICAL CHANGES

dwipujiastuti2305 — 2020-10-12 05:29:03 UTC

Explain how painting of an iron gate prevents it from rusting!

Jonathan dennes answer

2020-10-12 05:40:09 UTC

When iron gate is painted, the layer of paint prevents the contact of iron with air and moisture and so prevents rusting

RAISHA RENANDA AURASYIFA 7.10

2020-10-12 05:42:58 UTC

For rusting, iron must be in contact with both air and moisture: When iron gate is painted, the layer of paint prevents the contact of iron with air and moisture and so there is no rusting.

Devacetta Kautsar Danendra

2020-10-12 05:43:42 UTC

Painting of an iron gate prevents it from rusting because it cut the direct contact of iron from the environment and therefore there is no further exposure of iron to oxygen in moisture which is the causes for rusting.

2020-10-12 05:43:43 UTC

RASYA AQIL MARTFIANTORO
7.10

For rusting, iron must be in contact with both air and moisture: When iron gate is painted, the layer of paint prevents the contact of iron with air and moisture and so there is no rusting

Nala Vania Salsabila 7.10

2020-10-12 05:44:22 UTC

Iron must be in contact with both air dan moisture, Painting of an iron gate prevents direct contact of iron with water and air(oxygen) which are required for rusting.

2020-10-12 05:44:36 UTC

Gwen Aqila Hartono

Painting of an iron gate prevents it from rusting because it cut the direct contact of iron from the environment and therefore there is no further exposure of iron to oxygen in moisture which is the causes for rusting.

Winona Utomo

2020-10-12 05:44:53 UTC

Rusting is aided by both moisture (water) and air (oxygen). By painting an iron gate, we prevent its contact from the air and moisture present in the atmosphere. Hence, rusting is prevented.

Rachel davina putri

2020-10-12 05:44:56 UTC

iron must be in contact with both air and moisture When its painted, the layer of paint prevents the contact of iron with air and moisture and so there is no rusting.

Thank you

2020-10-12 05:45:01 UTC

NAMA:MUHAMMAD FAIRUS RAHMAN.T
KELAS.7.10
For rusting, iron must be in contact with both air and moisture: When iron gate is painted, the layer of paint prevents the contact of iron with air and moisture and so there is no rusting

Mutiara Anindya Putri

2020-10-12 05:45:07 UTC

For rusting, iron must be in contact with both air and moisture: When iron gate is painted, the layer of paint prevents the contact of iron with air and moisture and so there is no rusting.

Cika septi rahmadini

2020-10-12 05:46:29 UTC

For rusting,iron must be in contact with both air and moisture ,When irom gate is painted,the layer of paint prevents the contact of iron with air moiture and so there is no rusting

Dwi Putra Al-Rizky

2020-10-12 05:47:35 UTC

It is known that for rusting the presence
of oxygen and moisture is essential.
Painting prevents the iron gate from
coming in contact with oxygen and
moisture. it prevents it from rusting.

Muhammad Kafka Benecia

2020-10-12 05:48:18 UTC

7.10
For rusting, iron must be in contact with both air and moisture: When iron gate is painted, the layer of paint prevents the contact of iron with air and moisture and so there is no rusting.

2020-10-12 05:49:17 UTC

Yovela Diva Salsabila 7.10
The essential component for rusting is the contact of metal with oxygen and moisture. When the iron gate is painted, it protects the iron to get in contact with oxygen, hence prevents it from rusting.

2020-10-12 05:50:08 UTC

Hana Syakira Kamila iman
7.10
For rusting, iron must be in contact with both air and moisture: When iron gate is painted, the layer of paint prevents the contact of iron with air and moisture and so there is no rusting.

2020-10-12 05:50:57 UTC

Nama = Jan fadly anwar
Kelas = 7.10

" on iron fences grows due to oxidation reactions. The three elements that support the reaction are water, oxygen and dissolved salt. The oxidation reaction of the meeting of these three materials on the media causes it to rust.To prevent the iron fence from rusting, disconnection of the three materials must be done. One of the practical ways is to give the cat anti-rust coating on iron or metal."

Ladzuardhini Kalyla Ikhsan

2020-10-12 05:51:11 UTC

7.10
Painting of an iron gate prevents it from rusting because it cut the direct contact of iron from the environment and therefore there is no further exposure of iron to oxygen in moisture which is the causes for rusting.

Diyah kurniawati 7.10

2020-10-12 05:51:30 UTC

In order to prevent iron from rusting, we must choose a paint that is durable so that the iron does not rust, and rusting is aided by both moisture, water and oxygen.

2020-10-12 05:52:20 UTC

Fadli Mirza Putra Elya
7.10
For rusting, iron must be in contact with both air and moisture: When iron gate is painted, the layer of paint prevents the contact of iron with air and moisture and so there is no rusting.

Name: Anindya Putri Cahyaningtias 7.10

2020-10-12 05:52:38 UTC

For rusting iron must be in contact with both air
And then moisture when iron gate is painted the layer of paint prevents the contact of iron with air and moisture so there is no rusting

2020-10-12 05:54:04 UTC

LUTFI HERDIAWAN
7.10
For rust, avoid the iron that is exposed to moisture and air: when iron gate painted, the layer of paint prevents the contact of iron with air and moisture

2020-10-12 05:54:36 UTC

Nama= Naura Husniah Kamila
Kelas=7.10
For rusting,iron muat be in contact with both air and moisture: when iron gate is painted,the layer of paint prevents the contact of iron with air and moisture and so there is no rusting.

Jessica febriani hillary 7.10

2020-10-12 05:56:59 UTC

it the gate painhing so won't touched by water directly especially when raining so it will reduce broken or prevent the iron gate from rostin

2020-10-12 05:59:32 UTC

Nama: Halliza putri Mahadewi Santoso
Kelas: 7.10
Absen: 11

Because it uses paint, iron gates can be protected from contact between iron and rain or what is known as the weather.

2020-10-12 06:03:15 UTC

Nama : Williard Desnine
Kelas : 7.10
For rusting, iron must be in contact with both air and moisture: When iron gate is painted, the layer of paint prevents the contact of iron with air and moisture and so there is no rusting.

Amin Gogoh Mikha 7.10

2020-10-12 06:04:31 UTC

Iron gate could get rested if there is a contact with water and air.Therefore, painting the iron gate could prevent it from rusting. Since the paint creates a layer on it, the paint protects the iron gate from direct contact with water and air.

2020-10-12 06:05:08 UTC

Aria rad it ya bharata
7.10

When the iron gate is painted the layer of the paint
Prevent it from rusting

Raditya Alvaro D.P

2020-10-12 06:07:48 UTC

For rusting,iron must be in contact
with both air and moisture: when iron gate is painted,the layer of paint prevents the contact of iron with air and moisture and so there is no rusting.

2020-10-12 06:17:59 UTC

Muhammad Brilliant Aditama Pramono
7.10
"Iron must be in contact with both air and moisture When iron gate is painted, the layer of paint prevents the contact of iron with air and moisture and so there is no rusting"

Darren Christhoper Patte

2020-10-12 06:28:21 UTC

7.10
"Iron must be in contact with both air and moisture When iron gate is painted, the layer of paint prevents the contact of iron with air and moisture and so there is no rusting"

Name : Xavierrin Rizeni Nasution

2020-10-12 07:11:17 UTC

Absen : 33
Class : 7.10

For rusting iron must be in contact with both air
And then moisture when iron gate is painted the layer of paint prevents the contact of iron with airr and moisture so tthere is no rusting

Name : Rizqi Yudhistira Farras

2020-10-14 02:59:38 UTC

Class: 7.11
Attendee's number: 31

The essential component for rusting is the contact of metal with oxygen and moisture. When the iron gate is painted, it protects the iron to get in contact with oxygen, hence prevents it from rusting.

2020-10-14 03:00:35 UTC

Allesya Khiar Gunawan
VII.11

Rusting of iron happens when it comes in contact with air and moisture. By painting the iron gate, we basically are preventing the contact of water and air from iron.
the layer of paints prevents the gate from being rusty because it blocked the contact between water and air (oxygen) from the iron

Khairana Ghina Raihannisa

2020-10-14 03:03:13 UTC

7.11
For rusting iron must be in contact with both air.And then moisture when iron gate is painted the layer of paint prevents the contact of iron with air and moisture so there is no rusting.

2020-10-14 03:04:30 UTC

Joshua Putra Hadi Sutrisno
Class: 7.11
Absen: 15

Overlaying iron or other metal with a special iron paint

Danisworo Elang Darmawan

2020-10-14 03:04:31 UTC

kelas : 7.11
absen :8

to prevent rust we need to protect from air and water with paint

Reyner Elazaro Tampubolon, Kelas 7.11, Absen 29.

2020-10-14 03:04:46 UTC

Steel can be rusted by air and water if exposed. And to prevent the rust, something needs to cover the steel, so when it encountered rain or winds, the steel won't rust, and that is paint.

Nasha Azzura Rizkitafazila

2020-10-14 03:06:37 UTC

7.11
for rusting, iron must be in contact
with both air and moisture : when iron
gate is painted, the layer of paint prevents
the contact of iron with air and moisture
and so there is no rusting

Ryana Nathania Putri.W

2020-10-14 03:06:54 UTC

Class : 7.11
Absen : 32

Raffa Muhammad Yusuf

2020-10-14 03:07:21 UTC

class : 7.11
absen : 28

Rust is a reaction of iron and oxygen mixed with the presence of moisture or water, by painting the iron gate it prevents direct contact between iron with air moisture and oxygen and prevents rusting to happen.

Arini Nafija Izzatirroyan

2020-10-14 03:07:53 UTC

7.11
Absen: 3

Explain how painting of an iron gate prevents it from rusting:
For rusting, the presence of both oxygen and water (or water vapour) is required. The coat of the paint prevents direct contact of iron with air and oxygen and thus prevents it from rusting

2020-10-14 03:11:06 UTC

Muhammad Hafiid al hakam
7.11
Explain how painting of an iron gate prevents it from rusting:
For rusting, the presence of both oxygen and water (or water vapour) is required. The coat of the paint prevents direct contact of iron with air and oxygen and thus prevents it from rusting

Sabine Zuleika Nariswari

2020-10-14 03:11:56 UTC

Kelas: 7.11
Absen: 33
The essential component for rusting is the contact of metal with oxygen and moisture. When the iron gate is painted, it protects the iron to get in contact with oxygen, hence prevents it from rusting.

safina zeta miesha gutama

2020-10-14 03:11:56 UTC

class : 7.11
absen : 34

For rusting, iron must be in contact with both air and moisture: When iron gate is painted, the layer of paint prevents the contact of iron with air and moisture and so there is no rusting.

Azalea Riqqah Raerizela

2020-10-14 03:13:43 UTC

Class:7.11
Absen: 7
It is known that for rusting the presence of oxygen and moisture is essential. Painting prevents the iron gate from coming in contact with oxygen and moisture. Thus it prevents it from rusting.

mutiara pertiwi sudarman

2020-10-14 03:15:03 UTC

absen:23
class:7.11

rusting of iron happens when comes in contact with air and moisture when iron gate is painted the layer of paint prevents the contact of iron with air and moisture so there is no rusting.

Muhammad Danish Falah Utama

2020-10-14 03:15:18 UTC

7.11
Absen 21

How painting of an iron gate prevents it from rusting

Answer: Rusting of iron happens when it comes in contact with air and moisture. By painting the iron gate, we basically we are preventing the contact of water and air from iron.

Aramitha puspitasari Devi

2020-10-14 03:17:38 UTC

Kelas: 7.11
Absen: 2

For rusting, iron must be in contact with both air and moisture: when iron gate is painted, the layer of paint prevents the contact of iron with air and moisture and so there’s no rusting.

Jonathan Aryando Hamonangan Tambunan

2020-10-14 03:17:49 UTC

Kelas = 7.11
Rust on iron fences grows due to oxidation reactions. The three elements that support the reaction are water, oxygen and dissolved salt. To prevent the iron fence from rustibg, disconnection of the iron from the three materials must be done. One of the practical ways ia to provide ablayer of anti-rust paint on iron of metal.

Natalie Keira Permadi

2020-10-14 03:19:27 UTC

Kleas: 7.11
Absen: 26

Explain how painting of an iron gate prevents it from rusting!

For rusting, iron must be in contact with both air and moisture: When iron gate is painted, the layer of paint prevents the contact of iron with air and moisture and so there is no rusting.

Ayesha Farah Mahira

2020-10-14 03:21:58 UTC

Kelas : 7.11
Absen : 6

For rusting, iron must be in contact with both air and moisture: When iron gate is painted, the layer of paint prevents the contact of iron with air and moisture and so there is no rusting.

2020-10-14 03:25:48 UTC

Name : Fadlin Mirza Putra Elya
Class : 7.11
How to paint iron so as not to rusting :
1.Clean the entire surface of the iron, especially the rusted parts with 50:50 detergent or water and vinegar.
2.Coat the rusty iron with anti rust primer or primer.
3.Paint the entire surface of the iron by painting the iron so it doesn't peel off on top.

Lofty Athaillah Vika

2020-10-14 03:27:57 UTC

Kelas : 7.11
Absen : 19
Painting of an iron gate prevents it from rusting because it cut the direct contact of iron from the environment and therefore there is no further exposure of iron to oxygen in moisture which is the causes for rusting.

Johardian Athallah W.

2020-10-14 03:30:25 UTC

Kelas : 7.11
no : 13

Iron gate can rusting because contact of metal with oxygen and moisture. When iron gate is painted,the layer protect so prevents rusting.

Lintang Nisrina Kamil

2020-10-14 03:32:32 UTC

Kelas : 7.11
Absen : 18
Hari / tanggal : Rabu 14 Oktober 2020

For rusting, iron must be in contact with both air and moisture: When iron gate is painted, the layer of paint prevents the contact of iron with air and moisture and so there is no rusting and it covers the pores of the iron.

Rifat Alvaro Satyanegara

2020-10-14 03:42:07 UTC

Kelas : 7.11
Absen : 30

Explain how to painting of an iron gate prevents it from rusting!

The essential component for rusting is the contact of metal with oxygen and moisture. When the iron gate is painted, it protects the iron to get in contact with oxygen, hence prevents it from rusting.

Aurellia mediana putri

2020-10-14 03:46:16 UTC

Kelas : 7.11
Absen : 5

For rusting, iron must be in contact with both air and moisture: When iron gate is painted, the layer of paint prevents the contact of iron with air and moisture and so there is no rusting.

2020-10-14 03:49:21 UTC

Name:Muhammad Chicho Lee Mandji
Class:7.11
Absen:20

Clean the entire metal surface, especially the rusted parts with 50:50 detergent or water and vinegar. Scrub with a wire brush or sandpaper. Coat the rusty iron with anti-rust primer or primer. To speed up the process, use a spray model rather than a roll-on model.

Ery Emier Syarif

2020-10-14 04:07:31 UTC

Kelas : 1.77
Absen : 9
A chemical change result from a
Chemical reaction.
A physical change is when matter
Change froms but not chemical
Identity.

Example of chemical changes are
Burning, cooking, rusting, and rotting
Example of physical changes are
Boiling, melting, freezing, and shredding.

Physical changes can be undone, if
Energy is input. To reverse a chemical
Change via another chemical reaction
Is the only way.

2020-10-14 04:16:43 UTC

Arkhanza Farino Gustian
7.11
iron must be in contact with both air and when iron gate is planted,the layer of paint prevents the contact of iron with air and moisture and so there is no rusting

2020-10-14 05:35:12 UTC

Name: Giras Mahesworo Krisianto
Class: 7.9
Absen:14
Date: 14 October 2020
Answer:
Rusting is a chemical change of iron with oxygen to form iron oxide.

The process of rusting can be represented by the following equation:

Iron (Fe) + Oxygen (O2, from the air) + water (H2O) → rust (iron oxide Fe2O3)

For rusting, the presence of both oxygen and water (or water vapour) is essential. In fact, if the content of moisture in air is high, which means if it is more humid, rusting becomes faster.

Shireen Maulida Syarif

2020-10-14 05:35:39 UTC

Kelas : 7.9
Absen : 7.9

For rusting, iron must be in contact with both air and moisture: When iron gate is painted, the layer of paint prevents the contact of iron with air and moisture and so there is no rusting.

Navida Reza Aulia

2020-10-14 05:37:28 UTC

kelas: 7.9
absen: 23

For rusting, iron must be in contact with both air and moisture: When iron gate is painted, the layer of paint prevents the contact of iron with air and moisture and so there is no rusting.

2020-10-14 05:38:26 UTC

Name:Marsha Naila Daniswara
Class:7.9
Absen:19

*ANSWER*
The essential component for rusting is the contact of metal with oxygen and moisture. When the iron gate is painted, it protects the iron to get in contact with oxygen, hence prevents it from rusting

Name: Alby Syafa

2020-10-14 05:38:57 UTC

Class: 7.9

Rusting of iron happens when it comes in contact with air and moisture. By painting the iron gate, basically we are preventing the contact of water and air from iron

2020-10-14 05:39:53 UTC

Syafiq Nur Izzah
Kelas: 7.9
Absen: 33

Answer:

- Brush the metal (iron) that is rusted, then sand it until the part is completely clean.

- If there is still dirt and oil on the metal surface, clean it with a dry cloth.

- Apply iron paint that contains stainless. Thus, apart from being a primary paint layer, it is also a top coat or paint finish specially formulated in one package. Practical. Apart from being weather resistant paint, there are many decorative color options.

- If the application does not use the paint, you can use the primer (meni paint) first. Wait up to one day, then apply the finish paint.

2020-10-14 05:41:25 UTC

Name Sekartaji putri
Class 7.9

Question
Expalin how painting of an iron gate prevents it from rusting

Answer
For rusting, iron must be in contact with both air and moisture: When iron gate is painted, the layer of paint prevents the contact of iron with air and moisture and so there is no rusting.

Name:Akeyla Maghfira Rasyaputri

2020-10-14 05:41:28 UTC

Class:7.9
absen:03

Answer~
For rusting, iron must be in contact with both air and moisture: When iron gate is painted, the layer of paint prevents the contact of iron with air and moisture and so there is no rusting.

Nama = Muhammad Karim Daniswara

2020-10-14 05:41:49 UTC

Kelas = 7.9
Absen = 22

For rusting, iron must be in contact with both air and moisture: When iron gate is painted, the layer of paint prevents the contact of iron with air and moisture and so there is no rusting.

2020-10-14 05:41:51 UTC

Name: Barra Maliq Ali
Class: 7.9
No. Absen: 10
Answer:

Rusting of Iron happens when it comes in contact with air and moisture. By painting the iron gate, the layer of paint prevents the contact of Iron with air and moisture and so there is no rusting.

Name: Bagus Rizky Ariyanto

2020-10-14 05:43:46 UTC

Class: 7.9
Absen: 9
Answer:
For rusting, iron must be in contact with both air and moisture. When iron gate is painted, the layer of paint prevents the contact of iron with air and moisture, because of this there is no rusting.

Name : Gabriel bagawanbagaspati L

2020-10-14 05:43:58 UTC

Kelas = 7.9
absen = 12

For rusting, iron must be in contact with both air and moisture: When iron gate is painted, the layer of paint prevents the contact of iron with air and moisture and so there is no rusting.

2020-10-14 05:44:04 UTC

Nama: Grimaldi M Fadlan
Class:7.9

For rusting, iron must be in contact with both air and moisture: When iron gate is painted, the layer of paint prevents the contact of iron with air and moisture and so there is no rusting

2020-10-14 05:44:43 UTC

Nama : Adelia indracahyani
Kelas : 7.9
Absen : 01

For rusting, iron muat be in connect with both air and moisture. When iron gate is painted, the layer of paint prevents the contact of iron with air and moisture and so there is no rusting

2020-10-14 05:47:29 UTC

SABIAN KALIFI
kelas:7.9
Absen:28
Answer
For rusting, iron must be in contact with both air and moisture: When iron gate is painted, the layer of paint prevents the contact of iron with air and moisture and so there is no rusting.

Alecia claresta putri p

2020-10-14 05:49:21 UTC

Kelas : 7.9
Absen: 5

The cause of rusting iron must be in contact with both air and moisture when iron gate is painted, the layer of paint prevents the contact of iron with air and moisture and so there is no rusting.

Giras Mahesworo Krisianto

2020-10-14 05:50:03 UTC

Kelas: 7.9
Absen:14
Answer:

Rusting is aided by both moisture (water) and air (oxygen). By painting an iron gate, we prevent its contact from the air and moisture present in the atmosphere. Hence, rusting is prevented.

2020-10-14 05:51:29 UTC

Nama : Sulthan Vitto Athallah
Kelas : 7.9
No Absen : 32

For rusting, iron must be in contact with both air and moisture: When iron gate is painted, the layer of paint prevents the contact of iron with air and moisture and so there is no rusting.

Name: Moreno Septiano Yahya

2020-10-14 05:51:53 UTC

Class: 7.9
Atendee's Number: 21
Date: 14-10-2020

Question:
Explain how painting of an iron gate prevents it from rusting!

Answer: The essential component for rusting is the contact of metal with oxygen and moisture. When the iron gate is painted, it protects the iron to get in contact with oxygen, hence prevents it from rusting

Quinn Audrey Hananto

2020-10-14 05:52:44 UTC

Absen : 26
Class. : 7.9

For rusting, iron must be in contact with both air and moisture , When iron gate is painted, the layer of paint prevents the contact of iron with air and moisture and so there is no rusting.The essential component for rusting is the contact of metal with oxygen and moisture. When the iron gate is painted, it protects the iron to get in contact with oxygen, hence prevents it from rusting.

Adinda Syifa Nurani

2020-10-14 05:54:48 UTC

Kelas : 7.9
Absen :2
For rusting, iron must be in connect with both air and moisture. When iron gate is painted, the layer of paint prevents the contact of iron with air and moisture and ia no rusting

2020-10-14 05:55:00 UTC

Ghazi ahmad m
Kelas: 7.9
Absen: 13
Answer:
When iron gates is painted ,the layer of paint prevent the contact of iron with air and moisture and so there is no rusting

2020-10-14 05:56:23 UTC

Name:sebastian Matthew bryfi paisa
Kelas:7.9
Absen:29
Answer. Painting of an iron gate prevents it from rusting because it cut the direct contact of iron from the environment and therefore there is no further exposure of iron to oxygen in moisture which is the causes for rusting

2020-10-14 05:59:14 UTC

Nama: Putri Aulia Abdi
Kelas: 7.9
No. Absen: 25

when iron reacts with water and oxygen, the iron will turn brown (rust), so the paint layer prevents iron contact with water and oxygen and so there is no rusting

Nurul Hanny Aisyah Nasution

2020-10-14 06:03:09 UTC

Class : 7.9
Attendee's number : 24

Answer :
If the iron is in contact with air and moisture and is left for a long time, it will rust.

When a metal door is painted, a coat of paint prevents the metal from contacting air and moisture so that there is no rust.

2020-10-14 06:09:15 UTC

Nama : Raden Kazeta Merzy. S. R
Kls : 7.9
No : 27

For rusting, iron must be in contact with both air and moisture, when iron gate is painted the layer of paint prevents the contact of iron with air and moisture, so there is no rusting

Kiara Aisha Putri

2020-10-14 06:12:09 UTC

Kelas: 7.9
No. Absen: 17

Explain how painting of an iron gate prevents it from rusting:

Answer:
- Brush the metal (iron) that is rusted, then sand it until the part is completely clean.

- If there is still dirt and oil on the metal surface, clean it with a dry cloth.

- Apply iron paint that contains stainless. Thus, apart from being a primary paint layer, it is also a top coat or paint finish specially formulated in one package. Practical. Apart from being weather resistant paint, there are many decorative color choices.

- If the application does not use the paint, you can use the primer (meni paint) first. Wait up to one day, then apply the finish paint.

Gratia Theresa Magdalena Siahaan

2020-10-14 06:24:11 UTC

Class: 7.9
Absent serial number: 15
Answer:
For rusting, iron must be in contact with both air and moisture, when iron gate is painted the layer of paint prevents the contact of iron with air and moisture, so there is no rusting. When a metal door is painted, a coat of paint prevents the metal from contacting air and moisture so that there is no rust.

Tiara audi syafira

2020-10-14 06:33:01 UTC

Class: 7.9
No absen: 34
Answer:
For rusting, iron must be in contact with both air and moisture: When iron gate is painted, the layer of paint prevents the contact of iron with air and moisture and so there is no rusting.

2020-10-14 07:19:32 UTC

Kharissa Adyaputri Korua
7.11
For rusting iron must be in contact with both air.And then moisture when iron gate is painted the layer of paint prevents the contact of iron with air and moisture so there is no rusting.

2020-10-14 10:26:45 UTC

Mahammadou Labib Z.
Class:7.9

Explain how painting of an iron gate prevents it from rusting:
For rusting, the presence of both oxygen and water (or water vapour) is required. The coat of the paint prevents direct contact of iron with air and oxygen and thus prevents it from rusting