CH1001 Lecture Notes - Lecture 3: Chemical Equation, Chemical Formula, Stoichiometry

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coffeebear832

16 Jul 2018

School

James Cook University

Department

Course

CH1001

Professor

Mark Barnes

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Document Summary

A chemical reaction is the mixing of two or more species to produce new substances. A chemical equation describes what happens when a chemical reaction occurs. The law of conservation of mass says that atoms cannot be created or destroyed during a chemical reaction. Stoichiometric coefficients are used to balance an equation to meet this condition. It is useful to specify the physical states of the reactants and the products. This is done by writing (s) for solid, (l) for liquid or (g) for gas after the chemical formula. (aq), meaning "aqueous solution" can also be used to indicate that a particular substance is dissolved in water. Defined relative to c-12 as 12. 000amu (or u) The mole: (abbreviated mol) is the si unit amount of substance. A mole of any substance is the atomic mass (or molecular mass) expressed in rams.

Related Questions

I need help doing my lab homework, I missed lab that day because, I was sick and it's due.

Chemical Reactions and Equations Learning objectives To observe physical and chemical properties associated with chemical changes To be able to give evidence for the occurrence of a chemical reaction To write a balanced chemical equation To identify areaction as a combination, decomposition, precipitation, single or double replacement, or combustion reaction ntroduction When a substance undergoes a physical change, it changes its appearance but not its composition. For example, when ice melts to form water, it undergoes a physical change from solid to liquid. In a chemical change, the composition of a substance is changed to give a new substance with different physical and chemical properties. For example, when silver tarnishes, the shiny silver (Ag) changes to a dull gray silver sulfide (AgaS). Not only has the chemical formula changed from Ag to Agus, but also the physical properties (shininess) of the substance have changed. Some examples of physical and chemical changes are listed in Table 1 below. Table 1. Comparison of Physical and Chemical Changes Examples of Physical changes Examples and Evidence of Chemical Changes Change in state (melting, freezing, evaporating Formation of a gas (bubbles) subliming) Formation of a solid (precipitate) Change in size Tearing Change in Color Heat is given off or absorbed A solid dissolving in a solvent In a chemical reaction, atoms in the reactants are rearranged to produce new combinations of atoms in the products. However, the total number of atoms of each element in the reactants is equal to the total number of atoms in the products. This is true according to the Law of Conservation of Mass, which states that the total mass remains constant during a chemical reaction. In other words, matter cannot be created or destroyed in a chemical reaction. In a chemical equation, the reactants are shown on the left and the products are on the right. An arrow in between indicates that a chemical reaction occurs. Finally, the physical state of each compound is designated in parentheses after the chemical formula. Solid, liquid, gas, and aqueous (dissolved in water) are shown as(s,(n,(g), and (aq), respectively.

What is the balanced chemical equation for the reaction used to calculate ΔH°f of CaCO₃(s)?

If fractional coefficients are required, enter them as a fraction (i.e. 1/3). Indicate the physical states using the abbreviation (s), (l), or (g) for solid, liquid, or gas, respectively without indicating allotropes. Use (aq) for aqueous solution.

Express your answer as a chemical equation.

emeraldminnow227

What is the balanced chemical equation for the reaction used tocalculate standard enthalpy of formation of SrCO3(s)?

If fractional coefficients are required, enter them as a fraction(i.e. 1/3). Indicate the physical states using the abbreviation (),(), or () for solid, liquid, or gas, respectively. Use () foraqueous solution.

CH1001 Lecture Notes - Lecture 3: Chemical Equation, Chemical Formula, Stoichiometry

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