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- Overview
- Symbols in chemical equations
- Counting atoms using subscripts and coefficients
- Example 1:
- Example 2:
- Example 3:
- Try it: Counting atoms
Learn the meaning behind the symbols we use to represent chemical reactions.
•Reactants are the substances we start with. They are written on the left side of the arrow.
•Products are the substances that are created. They are written on the right side of the arrow.
•The arrow indicates that a chemical change has occurred.
•Coefficients are the larger-sized numbers that come before a chemical formula. They indicate how many separate instances of substance are present in the reaction. In the example above, two separate silver atoms (Ag) are produced (represented by "2Ag ").
•Subscripts are the smaller-sized numbers that come after an element symbol. These indicate there are multiple instances of the same element within a substance. In the example above, two silver atoms (Ag) are present in the silver sulfate compound (AgA2SOA4) .
Chemistry is a universal language used by people around the world. So, we as scientists can communicate with each other about chemistry even if we speak different languages in our day-to-day lives! All we have to do is follow consistent rules when talking about certain scientific concepts.
For example, we can describe the chemical reactions that occur in the physical world using chemical equations. These equations include symbols with specific meanings. The key features of a chemical equation are pointed out here:
•Reactants are the substances we start with. They are written on the left side of the arrow.
•Products are the substances that are created. They are written on the right side of the arrow.
•The arrow indicates that a chemical change has occurred.
•Coefficients are the larger-sized numbers that come before a chemical formula. They indicate how many separate instances of substance are present in the reaction. In the example above, two separate silver atoms (Ag) are produced (represented by "2Ag ").
It is often important to know how many atoms of each element are being shown in an equation. We can use the subscripts and coefficients in the equation to figure this out.
Let’s look at some examples:
How many oxygen atoms are represented in the formula AgNOA3 ?
•3 oxygen atoms
How many oxygen atoms are represented in the formula Mg(NOA3)A2 ?
•6 oxygen atoms
How many oxygen atoms are represented by 3Mg(NOA3)A2 ?
•18 oxygen atoms
Problem 1
How many hydrogen atoms are represented by 3CA2HA4 ?
hydrogen atoms
[Hint 1]
[Hint 2]
[Hint 3]
Nov 8, 2022 · Writing the formulas of ionic compounds. A quick way to determine the formula of an ionic compound (remember ionic compounds are metals bonded to nonmetals) is to use the crisscross rule. The crisscross rule uses the ionic charges of the ions to predict the formula of the ionic compound.
The mass, volume, and color of a substance are physical properties, and so is its ability to conduct electricity. What is density? Density is one of the most useful intensive properties of a substance, enabling chemists to more easily identify substances.
Nov 19, 2019 · Introduction to Chemistry: Learn about what chemistry is, what chemists do, and why you would want to study this science. Units & Measurements : Get a handle on the metric system and the common units used in chemistry.
Chemistry: An Introduction to General, Organic, and Biological Chemistry. Study with Quizlet and memorize flashcards containing terms like Why are models used in Organic Chemistry?, How do you determine the formal charge (FC) of an atom?, What are the dots in the lewis model of atoms? and more.
This equation is easily balanced by placing the coefficient "2" in front of molecule (HCl) to form the balanced equation (Mg) + 2 (HCl) (MgCl2) + (H2). you can think about it this way; 1 atom (Mg) + 2 compounds (HCl) combines in a reaction to form the products of 1 compound (MgCl2) + 1 Molecule (H2). Comment.
- 5 min
