Acids and carbonates word equations

In general an acid reacts with a carbonate or hydrogencarbonate to produce a salt, carbon dioxide gas and water….Key Concepts.

What is the gas produced when an acid reacts with carbonate?

When acids react with carbonates, such as calcium carbonate (found in chalk, limestone and marble), a salt, water and carbon dioxide are made. The carbon dioxide causes bubbling during the reaction, which is observed as fizzing. It can be detected by passing the gas through limewater, which will go cloudy.

general word equation:	sulfuric acid example :
acid	sulfuric acid
salt	metal sulfate
+	+
carbon dioxide	carbon dioxide

Which of the following gas is evolved when acids react with carbonates ammonia gas hydrogen gas carbon dioxide gas nitrogen gas?

Answer. Answer: Carbon Dioxide gas is liberated in rections of carbonates with acids.

What happens when an acid reacts with carbonate explain with example and equation?

When an acid reacts with a metal carbonate, then a salt, carbon dioxide and water are produced. Example: When dilute hydrochloric acid reacts with sodium carbonate, then sodium chloride, carbon dioxide and water are formed.

Acids react with most metals to form a salt and hydrogen gas. As discussed previously, metals that are more active than acids can undergo a single displacement reaction. For example, zinc metal reacts with hydrochloric acid, producing zinc chloride and hydrogen gas.

What type of reaction is calcium carbonate and hydrochloric acid?

The reaction of the acid with metal oxides forms salt and water: CuO + 2HCl = CuCl₂ + H₂O Reaction of hydrochloric acid and calcium carbonate Calcium carbonate reacts with hydrochloric acid in a double-replacement reaction.

What happens when you react calcium carbonate with hydrochloric acid?

Like all metal carbonates, calcium carbonate reacts with acidic solutions to produce carbon dioxide gas. It is this reaction that is responsible for limestone fizzing when dilute hydrochloric acid is placed on its surface.

Does calcium carbonate dissolve in hydrochloric acid?

Hydrochloric acid is stored in the cabinet under the hood on the right. Pour acid and water into each of the labeled beakers. Add calcium carbonate to the water and then to the acid and observe. The calcium carbonate will dissolve in the acid producing CO2 gas.

Is calcium carbonate hydrochloric acid a redox reaction?

Answer and Explanation: This is a typical neutralization reaction because calcium carbonate is a base while hydrochloric acid is an acid which forms a salt which is calcium chloride and water. This cannot be a redox reaction because there is no involvement of electron transfer.

What are 4 types of redox reactions?

Keep this in mind as we look at the five main types of redox reactions: combination, decomposition, displacement, combustion, and disproportion.

• Combination. Combination reactions “combine” elements to form a chemical compound.
• Decomposition.
• Displacement.
• Combustion.
• Disproportionation.

Is calcium oxygen a redox reaction?

Oxidation Numbers Consider the combustion of calcium metal in oxygen gas. This is a redox reaction.

What is the most common oxidation number of oxygen?

−2

Is calcium and water a redox?

On the other hand, the reaction of METALLIC calcium with water is a redox reaction….. Ca(s)→Ca2++2e− a. H2O+e−→12H2(g)↑⏐ ⏐⏐+HO− b.

Does calcium react with cold water or hot water?

The reaction of calcium with water is less violent. The heat evolved is not sufficient for the hydrogen to catch fire. Calcium starts floating because the bubbles of hydrogen gas formed stick to the surface of the metal. Magnesium does not react with cold water.

Does calcium explode in water?

In the following demonstration, a chunk of calcium metal is dropped into a beaker of distilled water. After a second or so, the calcium metal begins to bubble vigorously as it reacts with the water, producing hydrogen gas, and a cloudy white precipitate of calcium hydroxide….

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When a piece of calcium is dropped in water?

When a piece of calcium is dropped in water, it reacts with water and liberates hydrogen in the form of bubbles which brings the calcium upwards and makes it to float.

The alkali metals (Li, Na, K, Rb, Cs, and Fr) are the most reactive metals in the periodic table – they all react vigorously or even explosively with cold water, resulting in the displacement of hydrogen.

Why does calcium float on water when it reacts with water?

This is an exothermic reaction, i.e. heat is released. As the reaction proceeds, bubbles of H2 (g) and a white precipitate of Ca(OH)2are formed. The bubbles formed stick to the surface of calcium metal and make it lighter. Therefore, Calcium floats on water.

Does magnesium float on water?

Although magnesium is a promising low-density metal, years ago there were initial concerns about flammability and processing issues. The density of the new magnesium-matrix composite material is only 0.92 grams per cubic centimeter, compared to the density of water at 1.0 g/cc—meaning it will float on water.

Does sodium float on water?

lithium, sodium and potassium are less dense than water so they float on the surface of the water. sodium also melts to form a silvery-grey ball on the surface of the water.

Why does calcium float in water what is the Valency of phosphorus with atomic number 15?

8. Why does calcium float in water? Answer. It is because hydrogen gas is formed which sticks to surface of calcium, therefore it floats.

Is the Valency of oxygen?

The valency of oxygen is 2, because it needs two atoms of hydrogen to form water.

What is the Valency of 1 to 30 elements?

Valency of First 30 Elements

Element	Atomic Number	Valency
Valency of Cobalt	27	3, 2
Valency of Nickel	28	2
Valency of Copper (Cu)	29	2, 1
Valency of Zinc	30	2

How many electrons are in each shell?

Each shell can contain only a fixed number of electrons: The first shell can hold up to two electrons, the second shell can hold up to eight (2 + 6) electrons, the third shell can hold up to 18 (2 + 6 + 10) and so on. The general formula is that the nth shell can in principle hold up to 2(n2) electrons.

Why is 3rd shell 8 or 18?

The third shell of an atom has 18 electrons only not 8 electrons. You might be confused because first the electrons of 4s are filled and then the 10 electrons of 3d shells are filled. They are filled because of the n-l rule.

Why first shell is called K shell?

The names of the electron shell were given by a spectroscopist named Charles G Barkla. He named the innermost shell has k shell because he noticed that the X-rays emitted two types energies. These energies were named as type A that is higher energy X-ray and type B that is lower energy X-ray.

How many electrons are in the 5 shell?

50

Recommended textbook solutions

Learning outcomes

At the end of this, you should be able to:

– State how you know a reaction has taken place

-Write a word equation for a given reaction

– Write a balanced symbol equation for a reaction, given the symbols for the reactants

– Write a balanced symbol equation for a reaction when you have to look up the symbols from a table and/or using the Periodic table (Higher only)

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What you should already know

– What an element is– What a compound is– The difference between ionic and covalent compounds– What a molecule is– How to write the formula for a molecule or compound using symbols

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Word equations and balanced symbol equations

A reaction may happen when two or more chemicals are mixed. Sometimes you have to add heat (energy) before the reaction will occur.

Not all chemicals react together when they are mixed. We can tell a reaction has taken place if we see bubbles of gas, a change in colour, a change in temperature or a precipitate (a layer of solid in the bottom of the test tube that wasn’t there when you started). So vinegar (an acid) reacts with sodium bicarbonate – there are bubbles of gas and the test tube gets warm – but it doesn’t react with table salt (sodium chloride). The salt dissolves but nothing else happens, even if you heat the mixture.

A word equation helps us work out what has happened during a reaction.

Let’s look at the word equation for the reaction between sulphuric acid and calcium carbonate (limestone or marble).

We know a reaction happens because we see bubbles of gas and the test tube gets warm.

The clue to what the gas is is in the name of the reactants; if you add acid to a carbonate you always get carbon dioxide. (You could also test the gas; we know it is carbon dioxide because if we bubble it through limewater, the limewater goes ‘milky’.) In addition, if you react an acid with an alkali or base, like a carbonate, an oxide or a hydroxide, you always get water. (You need to know this for the chemistry exam.) The name of the acid gives you a clue to the name of the salt it forms.

Calcium carbonate + sulphuric acid→ calcium sulfate + carbon dioxide + water

Let’s look at another reaction. This is one you learn about in biology; respiration.

The reactants are glucose and oxygen, the products are carbon dioxide and water.

Glucose + oxygen→ carbon dioxide + water (+energy)

(This is almost the same as burning a hydrocarbon; you get the same products.)

Some reactions are very hard to describe in any other way than by a word equation. Not all substances have a chemical formula you can write down, for example, wood or a chocolate biscuit. Or the chemical formula may be one you don’t know, such as vinegar which is mainly a solution of something called ethanoic acid.

Word equations describe what is happening, but it is often more useful to know what each of the atoms, molecules or ions is doing. To do this, we use a balanced symbol equation. Sometimes you will have to look up the formulas for the compounds or even work them out using the Periodic Table.

‘Balancing’ just means making sure you have the same number of each sort of atom on each side.

This is important. We do not lose or gain mass during a chemical reaction. This is called ‘Conservation of mass’. You may have come across this idea already in Physics.

Let’s see how to write a balanced formula equation for the reaction between magnesium and hydrochloric acid. You know a reaction happens because there is fizzing. If you test the gas with a lighted splint, you get a ‘squeaky pop’, telling you hydrogen has been produced.

The word equation is

magnesium + hydrochloric acid → hydrogen + magnesium chloride.

If you look in the table of ions, you will see that magnesium makes ++ ions and chloride ions are – , so you need 2 chlorine ions to each ion of magnesium. You could also work this out by looking at the Periodic Table. Magnesium is in the second column of the Periodic table and chlorine is in the next-to-last column, so magnesium has 2 electrons in its outer shell to give away, and chlorine has 7 electrons in its outer shell, so needs 1 to make a full shell.

To write the symbol equation, first write down the reactants and products in symbol form: (mathrm{Mg}+mathrm{HCl} rightarrow mathrm{MgCI}_{2}+mathrm{H}_{2})

This doesn’t balance; we have 1 H and 1 Cl on the left-hand side and two of each on the right-hand side. So we need to add another HCl to make the equation balance:

(mathrm{Mg}+2 mathrm{HCl} rightarrow mathrm{MgCI}_{2}+mathrm{H}_{2})

The hydrochloric acid is in solution, and so is the magnesium chloride. You can show this by writing a little ‘aq’ (short for aqueous, which means ‘in water’) under the HCl and (mathrm{MgCI}_{2}). You could also show that the magnesium chloride is ionic and in solution by writing (mathrm{Mg}++(mathrm{Cl}-)_{2}) instead of MgCl.

You have probably seen the reaction between a group I metal and water; for example sodium and water. The sodium races around fizzing and there is a yellow flame too.

The fizzing tells us there is a gas being produced. The flame tells us there is also a lot of heat being produced; enough to ignite the gas. There is definitely a reaction going on!

The only substances involved are sodium and water and if you test the water afterwards with pH or litmus paper, you will find it is alkaline. The gas gives a ‘squeaky pop’ if it is tested with a lighted splint; it must be hydrogen.

Sodium + water→ hydrogen + sodium hydroxide.

In symbols:

(mathrm{Na}+mathrm{H}_{2} mathrm{O} rightarrow mathrm{H}_{2}+mathrm{NaOH})

This doesn’t balance, there are too many H’s on the right-hand side. If we add another Na, we also need another (mathrm{H}_{2} mathrm{O}) to make sure we have enough OH.

So we have:

(2 mathrm{Na}+2 mathrm{H}_{2} mathrm{O} rightarrow 2 mathrm{Na} mathrm{OH}+mathrm{H}_{2})

This is an example of a very important reaction; make sure you learn it, and the one for Group II metals. You’ll find that in the ‘some to try for yourself’ section.

Another reaction you might have seen or done is the reaction between copper II oxide and dilute sulphuric acid. This is a reaction requiring heat (and a lot of stirring) to make it happen. Copper II oxide (CuO) is a black insoluble powder. Dilute sulphuric is a clear liquid. The products are copper II sulfate and water. Copper II sulfate is a pretty blue colour. You can tell this reaction has happened because you have a change in colour.

Copper II oxide + dilute sulphuric acid → copper sulfate + water

Write the symbols:

(mathrm{Cu} mathrm{O}+mathrm{H}_{2} mathrm{SO}_{4} rightarrow mathrm{CuSO}_{4}+mathrm{H}_{2} mathrm{O})

There is the same number of atoms on each side; the equation is balanced. The dilute sulphuric acid and copper sulfate are both in solution, so you could write ‘aq’ underneath or show them as ions.

Let’s look at something which needs more balancing: the reaction between iron and chlorine. These are both elements and you aren’t adding anything else, so the product will be iron III chlorides, as long as you have lots of chlorine. Chlorine makes Cl- ions and iron III ions are +++.

Chlorine always comes as Cl2 molecules.

Iron + chlorine → iron III chloride

Write a formula equation:

(mathrm{Fe}+mathrm{CI}_{2} rightarrow mathrm{FeCI}_{3})

This doesn’t balance: you have 2 chlorines on the left-hand side and 3 on the right-hand side. You need to use a bit of clever maths here; 2 x 3 = 6. If you put a 3 in front of the (mathrm{CI}_{2}) and a 2 in front of the (mathrm{FeCI}_{3}), you have 6 chlorines on both sides. However, you now also have to put a 2 in front of the Fe on the left-hand side because you have 2 irons on the right-hand side:

(2 mathrm{Fe}+3 mathrm{CI}_{2} rightarrow 2 mathrm{FeCI}_{3})

You will find this ‘balancing trick’ with 2 and 3 useful for a lot of iron and also aluminium compounds. (The only — ion you are likely to come across is phosphate.) There is one to try in the ‘some to try for yourself’ section. But first here’s another example.

Let’s look at the reaction between aluminium hydroxide and sulphuric acid.It’s a reaction between an alkali and an acid, so we will get water as well as salt.

The salt is aluminium sulfate, and we can use the balancing trick to work out it is (mathrm{AI}_{2}left(mathrm{SO}_{4}right)_{3}).

Aluminium hydroxide + sulphuric acid → aluminium sulfate + water.

Begin by writing down the symbols:

(mathrm{Al}(mathrm{OH})_{3}+mathrm{H}_{2} mathrm{SO}_{4} rightarrow mathrm{Al}_{2}left(mathrm{SO}_{4}right)_{3}+mathrm{H}_{2} mathrm{O})

We can see straight away that we need 2 aluminium ions and 3 molecules of sulphuric acid on the left-hand side to make the aluminium sulfate.

(2 mathrm{Al}(mathrm{OH})_{3}+3 mathrm{H}_{2} mathrm{SO}_{4} rightarrow mathrm{Al}_{2}left(mathrm{SO}_{4}right) 3+mathrm{H}_{2} mathrm{O})

Now we have 6 OH’s and 6 H’s on the left. Each O needs 2 H’s to make water, so we have the right amount to make 6 (mathrm{H}_{2} mathrm{O}) with nothing left over.

The final balanced equation is:

(2 mathrm{Al}(mathrm{OH})_{3}+3 mathrm{H}_{2} mathrm{SO}_{4} rightarrow mathrm{Al}_{2}left(mathrm{SO}_{4}right)_{3}+6 mathrm{H}_{2} mathrm{O})

Take your time and remember to make sure you have the same number of each element or ion on each side.

You might find it helps to write the symbols in groups and cross them off as you use them:

These symbol equations all involve elements and ions, but we can write balanced symbol equations for other reactions, too.

If we burn the hydrocarbon gas propane in oxygen (or in the air), we get carbon dioxide and water.

Propane + oxygen → carbon dioxide + water

The formula for propane is (mathrm{C}_{3} mathrm{H}_{8}).

Write down a symbol equation:

(mathrm{C}_{3} mathrm{H}_{8}+mathrm{O}_{2} rightarrow mathrm{CO}_{2}+mathrm{H}_{2} mathrm{O})

You can see straight away that there are 3C’s on the left and 1 on the right, so you know there must be 3 (mathrm{CO}_{2}) ‘s. The 8 H’s will make 4 water molecules. So you need 4O’s for the water and 6 for the (mathrm{CO}_{2}) ‘s; 10 O’s or (5 mathrm{O}_{2}) ‘s.

The balanced equation is:

(mathrm{C}_{3} mathrm{H}_{8}+5 mathrm{O}_{2} rightarrow 3 mathrm{CO}_{2}+4 mathrm{H}_{2} mathrm{O})

Sometimes you end up with an odd number of O’s or H’s. If this happens, you just double everything up.

Propane’s cousin ethane C2H6 needs this:

(2 mathrm{C}_{2} mathrm{H}_{6}+7 mathrm{O}_{2} rightarrow 4 mathrm{CO}_{2}+6 mathrm{H}_{2} mathrm{O})

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Summary

• You know a reaction has happened because you get bubbles of gas, a change in colour, a change in temperature or a precipitate.
• You can write a reaction as a word equation. This is useful if you don’t know the formula or for complicated compounds/substances.
• You can also write a reaction as a balanced symbol equation. Balanced means having the same number of atoms of each element on each side of the equation.
• You might need to use the Periodic Table or a table of ions to work out the formulas of the things you are reacting.
• You need to know what happens when you react an acid with an oxide, a hydroxide or a carbonate.
• You need to know what happens when you react to a Group I or II metal with water.
• You need to know what happens when you burn a hydrocarbon.
• You need to be able to write word equations for respiration and photosynthesis.

Some to try for yourself

1. Write a word equation for the reaction that occurs when a candle is burned. (Candle wax is a hydrocarbon.)
2. Write a word equation for the reaction between potassium and water.
3. Write a balanced formula equation for the reaction between calcium metal and water.
4. Write a balanced formula equation for the reaction between magnesium carbonate (left(mathrm{MgCO}_{3}right)) and sulphuric acid (left(mathrm{H}_{2} mathrm{SO}_{4}right)).
5. Write a balanced formula equation for the reaction between iron II oxide (FeO) and nitric acid (left(mathrm{HNO}_{3}right)).
6. Write a balanced formula equation for the reaction between sodium carbonate and hydrochloric acid.
7. Ammonia (left(mathrm{NH}_{3}right)) is made by reacting together nitrogen and hydrogen.
8. Write a balanced formula equation for this reaction.
9. Iron is extracted from haematite iron ore (Iron III oxide) by heating with carbon. Write a balanced formula equation for this reaction. Write a balanced formula equation for the reaction between aluminium oxide and nitric acid.
10. Quicklime is made by heating limestone, calcium carbonate. A gas is given off during the reaction. Quicklime is alkaline and reacts with water to form calcium hydroxide. Write balanced formula equations for these two reactions?

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Answers

Remember to write a word equation before you write the balanced formula equation to make sure you don’t forget anything.

Answer 1

candle wax + oxygen → carbon dioxide + water

Answer 2

potassium + water → potassium hydroxide + hydrogen

Answer 3

calcium + water → calcium hydroxide + hydrogen

(mathrm{Ca}+2 mathrm{H}_{2} mathrm{O} rightarrow mathrm{Ca}(mathrm{OH})_{2}+mathrm{H}_{2})

Calcium is Group II so it is ++. Otherwise, it’s the same as the reaction between sodium and water. The calcium fizzes and the test tube gets warm.

Answer 4

magnesium carbonate + sulphuric acid → magnesium sulfate + carbon dioxide + water

(mathrm{MgCO}_{3}+mathrm{H}_{2} mathrm{SO}_{4} rightarrow mathrm{MgSO}_{4}+mathrm{CO}_{2}+mathrm{H}_{2} mathrm{O})

In the acid/carbonate reaction, the carbonate ion gives an oxygen atom to the hydrogen from the acid to form a water molecule.

Magnesium carbonate is the chemical name for gypsum, a soft white rock.

Answer 5

Iron II oxide + nitric acid → iron II nitrate + water

(mathrm{FeO}+2 mathrm{HNO}_{3} rightarrow mathrm{Fe}left(mathrm{NO}_{3}right)_{2}+mathrm{H}_{2} mathrm{O})

Transition metals like iron and copper often have more than one ‘oxidation state’ – they can have different numbers of +. Watch out for things like iron II and copper I.

Answer 6

Sodium carbonate + hydrochloric acid → sodium chloride + carbon dioxide + water

(mathrm{Na}_{2} mathrm{CO}_{3}+2 mathrm{HCl} rightarrow 2 mathrm{NaCl}+mathrm{CO}_{2}+mathrm{H}_{2} mathrm{O})

Something alkaline + an acid gives a salt. This reaction gives ‘table salt’. Sodium carbonate is washing soda.

Answer 7

(mathrm{N}_{2}+3 mathrm{H}_{2} rightarrow 2 mathrm{NH}_{3})

This is an important reaction because it is used to make ammonia for fertiliser.It is what is called an ‘equilibrium’ reaction; not all the reactants are turned into a product. You will learn more about this reaction in a later unit of your course.

Answer 8

Iron III oxide + carbon → iron + carbon dioxide

(2 mathrm{Fe}_{2} mathrm{O}_{3}+3 mathrm{C} rightarrow 2 mathrm{Fe}+3 mathrm{CO}_{2})

You will learn about the extraction of metals later in your course.

Answer 9

Aluminium oxide + nitric acid → aluminium nitrate + water

(mathrm{Al}_{2} mathrm{O}_{3}+6 mathrm{HNO}_{3} rightarrow 2 mathrm{Al}left(mathrm{NO}_{3}right)_{3}+3 mathrm{H}_{2} mathrm{O})

Aluminium reacts in a similar way to group II metals but forms +++ ions.

Since there are 2 Al ions there need to be (6 mathrm{NO}_{3}) ions.

Answer 10

The gas given off is carbon dioxide. This means that the first reaction is

(mathrm{CaCO}_{3} rightarrow mathrm{CO}_{2}+mathrm{CaO})

This tells you that quicklime is calcium oxide.

The calcium oxide is reacted with water. Nothing is given off, so the product must be calcium hydroxide. This is known as slaked lime.

(mathrm{CaO}+mathrm{H}_{2} mathrm{O} rightarrow mathrm{Ca}(mathrm{OH})_{2})

These are very important reactions.

Calcium oxide is used in the manufacture of cement, concrete and mortar (used to stick bricks together). A lot of heat is given out by the second reaction (it is exothermic) – if you’ve ever mixed cement you will know it gets hot. This is why.

Lime is also used to ‘sweeten’ clay soils to make them easier to work and more productive.

Slaked lime is dissolved in water to make lime water, which you use to test for carbon dioxide. The milkiness is due to the particles of insoluble calcium carbonate formed when calcium hydroxide reacts with carbon dioxide.

(mathrm{Ca}(mathrm{OH})_{2}+mathrm{CO}_{2} rightarrow mathrm{CaCO}_{3}+mathrm{H}_{2} mathrm{O})

Word equations – information sheet

Word equations are the shorthand used by scientists to describe chemical reactions. There are

many possible chemical reactions BUT you are not expected to know about all of them. Luckily

many reactions are of similar types. You MUST memorise these five!

1. metal + acid

When a (reactive) metal reacts with an acid, the reaction produces a salt, and hydrogen gas is

released. The salt produced depends upon the metal and the acid. If zinc reacts with sulfuric

acid, then the salt produced is zinc sulfate.

metal + acid → salt + hydrogen

2. metal carbonate + acid

Metal carbonates also react with acid to give a salt and water and carbon dioxide gas is given

off. The salt produced depends upon which acid and which metal carbonate react. If calcium

carbonate reacts with hydrochloric acid, the salt is calcium chloride.

metal carbonate + acid → salt + carbon dioxide + water

3. acid + base / alkali (an alkali is a base that dissolves in water)

When a base & an acid react, the product is a salt and water. The particular salt produced

depends upon which acid and which base reacted. When hydrochloric acid reacts with sodium

hydroxide, the salt produced is sodium chloride (yes, this really is what we know as “salt”).

acid + base/alkali → salt + water

4. metals + air

Metals react with oxygen in the air to form oxides. For example, when sodium reacts with

oxygen the compound is called sodium oxide. Reactive metals burn (eg Na burns to form

sodium oxide) while less reactive metals form an oxide layer (eg Cu reacts to form a layer of

copper oxide on the metal).

metal + oxygen → metal oxide

5. metals + water

The alkali metals in group 1 and the alkaline metals of group 2 are so called because, when

they react with water, they form alkalis (soluble bases) and hydrogen. Eg When sodium reacts

with water, it forms sodium hydroxide and hydrogen. Other reactive metals may also react with

hot water.

metal + water → metal hydroxide + hydrogen

These examples show the patterns that are found in FIVE important types of reaction. If you

learn the patterns, you should find it easy to work out how to complete word equations.

If you know these patterns you can then attempt symbol equations if you are asked to write

them.

If you are asked to write a word

equation don’t include symbols

like CO2 because you are too

lazy to write “carbon dioxide” OR

are trying to be smart / show off!

They will be marked wrong!

Sulfuric acid makes salts

called sulfates.

Hydrochloric acid makes

salts called chlorides.

Learn this!!