Stockland Green School Page 1 Q1. Calcium carbonate tablets are used to treat people with calcium deficiency. (a) Calculate the relative formula mass (Mr) of calcium carbonate.
Solving for the atomic mass of calcium carbonate (CaCo3)
- For 63 Cu the atomic mass is less than 63 so this must be the dominant factor. Note that, it was found the rest mass of an atomic nucleus is measurably smaller than the sum of the rest masses of its constituent protons, neutrons and electrons.
- Calcium carbonate (CaCO 3) is one of the common compounds of calcium. It is heated to form quicklime (CaO) which is then added to water (H 2 O). This forms another material known as slaked lime (Ca(OH) 2 ) which is an inexpensive base material used throughout the chemical industry.
- Atomic mass Atomic mass in an atom or group of an atom is the sum of the masses of protons, neutrons and electrons. The electrons have very less mass in comparison with protons or neutrons so the mass of electrons is not influenced in the calculation. The atomic mass of calcium is 40.078 g/mol.
Need to know the atomic mass of a calcium carbonate molecule? Our molar mass calculator uses the periodic table and the chemical formula to solve for the molar mass of a chemical compound based on the compound's empirical formula. The calculator takes the elemental composition of the compound and weighs the elements to get an empirical formula mass. Note that the calculator assumes a pure substance - if you're aware of dilution or impurities, make appropriate adjustments for the molarity of a given substance.
This project started with as a molar mass calculator for chemical reactions. You can use our calculator to solve for the theoretical yield of an experiment. We also have a percent yield calculator which can help you apply this to actual experiments. Use the mole ratio and empirical formula to understand the limits of the reactants.
Other terms: atomic mass of calcium carbonate, molar mass of calcium carbonate, molecular mass,
How Does The Molar Mass Calculator Work?
We take the formula you provide (NaCl - common table salt - in our default example) and unpack it into the component elements. Then we compare each atom against a table of the standard atomic weights for that element. We present the results in a table at the bottom of the molar mass calculator - it will show the count of atoms, the atomic weight of each element, and the molecular weight for the molecule. It solves for total mass of a molecular formula (average molecular weight).
From there we break the formula for calcium carbonate into parts - a Calcium atom, a Cobalt atom, etc.
We don't have brackets implemented (yet), so you will need to unpack any bracketed expressions. They don't affect the weight anyhow. Simply take each element and multiple it by the number of times the bracketed structure occurs. For example: (C6H5)3PCCO => C18H15PCCO
Finding Molar Mass for Other Chemical Compounds
Our molar mass calculator has this for a variety of other compounds: sodium chloride, carbon dioxide, sulfuric acid, glucose...
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![Relative Relative](/uploads/1/1/1/8/111874701/767434669.jpg)
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FAQ - Molar Mass Calculator
What is Molar Mass in Chemistry?
Molar mass is an important concept in adapting chemical formulas to real world conditions. We may be able to balance a chemical equation and determine that one molecule of hydrogen combines with two of oxygen to make water (or the compound of your choice). But how would you set up the materials in the laboratory? Or if you were, for example, buying oxygen for a process, how would you determine how much to use to make a given quantity of water? Molar mass allows us to convert a chemical reaction into specific amounts of reagents required for the process. By converting the atomic interaction into grams, we can measure and use an appropriate amount of the necessary reagents. Formula mass helps us solve for this.
What Is Relative Atomic Mass / Relative Molecular Mass / Average Molecular Weight?
The relative atomic mass of a compound is the ratio of the average mass of the elements in a chemical compound to the atomic mass constant, which is defined as 1/12 the mass of a carbon 12 atom. For a single sample, the relative atomic mass of the sample is the weighted arithmetic mean of the masses of the individual atoms present in the sample (also known as the average atomic mass). This will vary by isotope of the element (carbon-12 vs. carbon-13, for example, since the two isotopes have a different atomic mass due to additional neutrons). In the real world, this can vary based on where the sample was collected - due to variances in the specific isotopes of the elements present (driven by differences in radioactive decay and how the material was aggregated to begin with).
How to find Molar Mass
Take a standard chemistry formula for a molecule, split it up into the component atoms, and look up the molar weight of each atom. Add the weight of the atoms in the molecule and you have the molar mass for the molecule.
Bemused by chemistry? Read on...
Some very basic chemistry will help a lot with understanding how cement is made and how it works. If you missed out on chemistry at school, or it just seems a long time ago, the following short notes might be useful.
Basic Chemistry 1: Chemical symbols
Chemical symbols are abbreviated forms of the names of chemical elements, eg: Ca (calcium); Si (silicon); K (potassium).
Symbols are usually based on the Latin names, so they don't always resemble the English names especially for elements known in antiquity (eg: Au-gold, aurum).
Some useful elemental symbols in the context of cement follow, with their approximate atomic weights:
Symbols are usually based on the Latin names, so they don't always resemble the English names especially for elements known in antiquity (eg: Au-gold, aurum).
Some useful elemental symbols in the context of cement follow, with their approximate atomic weights:
Element | Symbol | Atomic weight |
Hydrogen | H | 1 |
Carbon | C | 12 |
Oxygen | O | 16 |
Nitrogen | N | 18 |
Sodium | Na | 23 |
Magnesium | Mg | 26 |
Aluminium | Al | 27 |
Silicon | Si | 28 |
Phosphorus | P | 31 |
Sulfur | S | 32 |
Chlorine | Cl | 35.5 |
Potassium | K | 39 |
Calcium | Ca | 40 |
Titanium | Ti | 48 |
Chromium | Cr | 52 |
Manganese | Mn | 55 |
Iron | Fe | 56 |
Basic Chemistry 2: Chemical formulae
A chemical formula is more than just a convenient short form of the name of a chemical - they indicate its composition.
For example, common table salt is sodium chloride, NaCl. One molecule of sodium chloride contains one atom of sodium and one of chlorine.
For example, common table salt is sodium chloride, NaCl. One molecule of sodium chloride contains one atom of sodium and one of chlorine.
One molecule of calcium carbonate, CaCO3, contains one atom of calcium, one of carbon and three of oxygen.
Basic Chemistry 3: Atomic weights (also known as relative atomic masses)
In the old days, atomic weights were based on hydrogen with an atomic weight of 1. This meant that calcium, with an atomic weight of 40, is 40 times as massive for the same number of atoms as hydrogen.
In other words, if you have 1 gram of hydrogen and 40 grams of calcium, there would be the same number of atoms in each.
These days, atomic weights are not based on hydrogen, but on one-twelfth of carbon-12. There have been other definitions as well, but they are all the same to within about 1%. Although called atomic weights, they are not really weights because they are ratios and therefore dimensionless but the term atomic weight is kept for historical reasons.
The basic point is that the atomic weight tells you the relative masses of atoms. A sodium atom is 23 times as massive as a hydrogen atom and a sulfur atom is twice as massive as an oxygen atom (see the Table above and you'll get the idea).
This is useful because with this knowledge we can calculate how much, by weight, of each element is present in compounds. It also means we can weigh stuff out in the right proportions to make different compounds.
Sodium chloride again: the atomic ratio of sodium to chlorine is 1:1. There is one atom of sodium and one of chlorine. The proportions by weight are different. The weight (relative atomic mass) of sodium is 23 and of chlorine is 35.5. If we add these together we get the formula weight of a sodium chloride molecule: 23+35.5=58.5.
So, the proportion of sodium in sodium chloride is: 23/58.5 x 100% = 39.3% by mass.
The proportion of chlorine in sodium chloride is: 35.5/58.5 x 100% = 60.7% by mass.
In other words, if you have 1 gram of hydrogen and 40 grams of calcium, there would be the same number of atoms in each.
These days, atomic weights are not based on hydrogen, but on one-twelfth of carbon-12. There have been other definitions as well, but they are all the same to within about 1%. Although called atomic weights, they are not really weights because they are ratios and therefore dimensionless but the term atomic weight is kept for historical reasons.
The basic point is that the atomic weight tells you the relative masses of atoms. A sodium atom is 23 times as massive as a hydrogen atom and a sulfur atom is twice as massive as an oxygen atom (see the Table above and you'll get the idea).
This is useful because with this knowledge we can calculate how much, by weight, of each element is present in compounds. It also means we can weigh stuff out in the right proportions to make different compounds.
Sodium chloride again: the atomic ratio of sodium to chlorine is 1:1. There is one atom of sodium and one of chlorine. The proportions by weight are different. The weight (relative atomic mass) of sodium is 23 and of chlorine is 35.5. If we add these together we get the formula weight of a sodium chloride molecule: 23+35.5=58.5.
So, the proportion of sodium in sodium chloride is: 23/58.5 x 100% = 39.3% by mass.
The proportion of chlorine in sodium chloride is: 35.5/58.5 x 100% = 60.7% by mass.
Let's do a slightly more complicated one. The formula for calcium carbonate is CaCO3 and from the Table above, the relative atomic mass of calcium is 40, of carbon is 12 and of oxygen is 16.
![Expected mass of calcium carbonate Expected mass of calcium carbonate](/uploads/1/1/1/8/111874701/565277764.jpg)
In calcium carbonate, we have one atom of calcium, one of carbon and three of oxygen. So, the formula weight of calcium carbonate is: 40+12+48=100.
So, calcium carbonate contains 40% calcium, 12% carbon and 48% oxygen by mass.
So, calcium carbonate contains 40% calcium, 12% carbon and 48% oxygen by mass.
A little pedantry...
The term 'formula weight' has been replaced by 'molar mass'. Understanding the formula weight is easy, it is just the sum of the atomic weights of all the atoms in the formula for a compound. The molar mass is numerically the same, multiplied by 1 gram/mol. The reason for this is to make the expression dimensionally correct. Atomic weights aren't weights, they are ratios; for calcium carbonate, the molar mass is 100 grams per mol.
'Mol' is the symbol for 'mole' and is linked to the number of atoms in 12 grams of carbon-12, the same as atomic weights. The mole can be applied to elements or compounds.
If that is a bit confusing, look at these illustrative examples to see how moles are used: one mole of calcium weighs 40 grams, one mole of iron weighs 56 grams and one mole of calcium carbonate weighs 100 grams. From these, you should be able to see how moles are used.
'Mol' is the symbol for 'mole' and is linked to the number of atoms in 12 grams of carbon-12, the same as atomic weights. The mole can be applied to elements or compounds.
If that is a bit confusing, look at these illustrative examples to see how moles are used: one mole of calcium weighs 40 grams, one mole of iron weighs 56 grams and one mole of calcium carbonate weighs 100 grams. From these, you should be able to see how moles are used.
For example, try these, using the Table of atomic weights above:
a) How much does 1 mole of potassium weigh?
b) How much do 2 moles of water (H2O) weigh?
c) How many moles are represented by 56g of silicon?
(Answers below)
Basic Chemistry 4: Anions and cations
Atoms are normally electrically neutral because they have the same number of protons (positively charged) as electrons (negatively charged). However, if it gains or loses one or more electrons, an atom becomes electrically charged. For reasons to do with the number of electrons in the outer shell of the atom, some atoms easily gain one or more electrons and others lose one or more electrons.
Those that gain electrons become negatively charged and are called anions. Those that lose an electron become positively charged and are called cations.
If you want more detail, get a book, or go online, and look up valence electrons.
However for now, and to keep it simple, just learn the following:
In normal cement-related compounds, cations and anions have the following charges (valencies):
Hydrogen +1
Carbon +4
Nitrogen +4
Sodium, potassium +1
Calcium, magnesium +2
Aluminium +3
Silicon +4
Phosphorus +5
Oxygen -2
Chlorine -1
Hydroxide (OH) -1
Chromium +3 or +6
Manganese +2 or +3 (can have others)
Iron +2 or +3
Sulfate, sulfur trioxide, (SO3) -2
Those that gain electrons become negatively charged and are called anions. Those that lose an electron become positively charged and are called cations.
If you want more detail, get a book, or go online, and look up valence electrons.
However for now, and to keep it simple, just learn the following:
In normal cement-related compounds, cations and anions have the following charges (valencies):
Hydrogen +1
Carbon +4
Nitrogen +4
Sodium, potassium +1
Calcium, magnesium +2
Aluminium +3
Silicon +4
Phosphorus +5
Oxygen -2
Chlorine -1
Hydroxide (OH) -1
Chromium +3 or +6
Manganese +2 or +3 (can have others)
Iron +2 or +3
Sulfate, sulfur trioxide, (SO3) -2
It may be a bit tedious learning these but it is worth the effort. If you remember the formulae for some compounds as well, you can work out valencies you have forgotten because the charges have to balance.
For example, everyone knows the formula of water is H2O. If you remember hydrogen has a charge of +1 but you forgot about oxygen, water has to be electrically neutral, so the oxygen anion must have a charge of -2.
If you remember that the sodium cation has a charge of +1 and the hydroxide anion -1, you can work out that the formula for sodium hydroxide must be NaOH; it cannot be, for example, Na2OH because it would then be electrically charged by +1.
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For example, everyone knows the formula of water is H2O. If you remember hydrogen has a charge of +1 but you forgot about oxygen, water has to be electrically neutral, so the oxygen anion must have a charge of -2.
If you remember that the sodium cation has a charge of +1 and the hydroxide anion -1, you can work out that the formula for sodium hydroxide must be NaOH; it cannot be, for example, Na2OH because it would then be electrically charged by +1.
If you find these basic chemistry short notes useful let us know using the Contact Form and we'll expand them.
If you've found this basic chemistry page useful, why not sign up for our free Newsletter to get updates of new pages on this website and of our publications and other resources for learning about cement?
Answers: a) 39g; b) 36g; c) 2.
Atomic Mass Of Calcium Carbonate
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