Сборник текстов на казахском, русском, английском языках для формирования навыков по видам речевой деятельности обучающихся уровней среднего образования



жүктеу 7.37 Mb.
бет41/67
Дата13.09.2017
өлшемі7.37 Mb.
1   ...   37   38   39   40   41   42   43   44   ...   67

Reactivity Series Chart


Back to Top

We can summarize the reactivity of different metals in a reactivity series chart.



Metal

Symbol

Reactivity

Extraction

Lithium

Li

displaces H2 gas from water, steam and acids and forms hydroxides

Electrolysis

Potassium



Strontium

Sr 

Calcium

Ca 

Sodium

Na 

Magnesium

Mg 

displaces H2 gas from steam and acids and forms hydroxides

Aluminium

Al 

Carbon



Included for comparison




Manganese

Mn 

displaces H2 gas from steam and acids and forms hydroxides

Smelting with coke

Zinc

Zn 

Chromium

Cr 

Iron

Fe 

displaces H2 gas from acids only and forms hydroxides

Cadmium

Cd 

Cobalt

Co 

Nickel

Ni 

Tin

Sn 

Lead

Pb

Hydrogen gas

H2

included for comparison




Antimony

Sb

combines with O2 to form oxides and cannot displace H2

Heat or physical extraction methods

Arsenic

Ar 

Bismuth

Bi 

Copper

Cu 

Mercury

Hg 

found free in nature, oxides decompose with heating

Silver

Ag 

Paladium

Pd 

Platinum

Pt 

Gold

Au 

All metals have a tendency to lose electrons and form metal ions. In other words, all metals are good reducing agents and easily oxidise themselves. 

M →→ Mn+ + ne-

The reactivity series of elements can be shown in another way, which includes oxidation reaction of each metal to the respective metal ion. It gives information regarding the reducing power of the metal atom and the oxidation number of the metal ion.
Exothermic and endothermic reactions
All processes can be classified into one of two categories: exothermic and endothermic. In an exothermic process, energy is released, while in an endothermic process, energy is stored. This section will specifically cover exothermic and endothermic chemical reactions, but almost any process can be described as releasing or storing energy.

The concept of giving off or storing energy can sometimes be a bit confusing, so let's go over some of the basic types of energy that you'll encounter in your chemistry class, and what it means to give off and store each type of energy.

Heat: Heat energy is the energy that accompanies temperature changes. If heat energy is being released then the reaction from which it is released will become hotter. If heat energy is being stored, then reaction will become colder.

Light: If light energy is being given off, then the reaction will glow. If it's being stored, then the reaction will seemingly proceed on its own without any catalyst present without any heat being evolved or absorbed.

Mechanical energy: If mechanical energy is being stored, then the volume and/or pressure of the reaction will get smaller. If mechanical energy is being given off, then the opposite will be true.

The most common change in energy that you'll witness in your chemistry class will be changes in heat energy. It can be measured with a bomb calorimeter. Energy released or stored in a reaction will often be expressed written as ΔH, or a change in enthalpy. A positive ΔH means that energy is stored and the reaction is endothermic. A negative ΔH means that energy is released and the reaction is exothermic. It is usually expressed in kilojoules (kJ) or joules (J).




Каталог: uploads -> doc -> 0a52
doc -> Пєн атауы: Математика
doc -> Сабаќтыњ тарихы: ХІХ ѓасырдыњ 60-70 жылдарындаѓы ќазаќ халќыныњ отарлыќ езгіге ќарсы азаттыќ к‰ресі
doc -> 1 -сынып, аптасына сағат, барлығы 34 сағат Кіріспе (1 сағат)
doc -> Сабақтың тақырыбы: XVIII ғасырдың бірінші ширегіндегі Қазақ хандығының ішкі және сыртқы жағдайы Сабақтың мақсаты
doc -> Сабақтың тақырыбы: XVIII ғасырдың бірінші ширегіндегі Қазақ хандығының ішкі және сыртқы жағдайы
0a52 -> Жантақ өсімдігі туралы жалпы сипаттама
0a52 -> Отбасылық ТӘрбие, оның тарихи негіздері
0a52 -> Өз білімін жетілдіру


Достарыңызбен бөлісу:
1   ...   37   38   39   40   41   42   43   44   ...   67


©kzref.org 2019
әкімшілігінің қараңыз

    Басты бет