Q&A for How to Write a Chemical Equation

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  • Question
    In a formula, is it necessary for us to arrange them in order from the element with least atoms to the element with the most atoms?
    Meredith Juncker, PhD
    Scientific Researcher
    Meredith Juncker is a PhD candidate in Biochemistry and Molecular Biology at Louisiana State University Health Sciences Center. Her studies are focused on proteins and neurodegenerative diseases.
    Scientific Researcher
    Expert Answer
    No, it is not necessary to do this. As long as the reactants remain on the left side of the arrow and the products remain on the right side, the compounds can be written in any order, regardless of how many atoms there are in each element.
  • Question
    Can balancing be done with a quicker method than the algebraic one?
    Meredith Juncker, PhD
    Scientific Researcher
    Meredith Juncker is a PhD candidate in Biochemistry and Molecular Biology at Louisiana State University Health Sciences Center. Her studies are focused on proteins and neurodegenerative diseases.
    Scientific Researcher
    Expert Answer
    Unfortunately, no. Balancing equations is often a trial and error process. A good tip to follow is to start by balancing an element that appears in only one reactant and product and then work from there. Make sure the coefficients you use to balance are in their most reduced form (if the only coefficients you have in the equation are 2 and 6, you would write them as 1 and 3.)
  • Question
    Is it necessary to write down the status of the element under it?
    Community Answer
    It depends upon the situation, but it's usually not necessary. The status is usually written just to make the equation more informative. If you are asked to write it for an assignment or examination, however, then you should write it down.
  • Question
    What is the valency of bromine?
    Community Answer
    Bromine has 7 valence electrons, therefore is an ionic compound. It is able to gain an electron to form a bromide ion with a -1 charge. It is capable of making one covalent bond.
  • Question
    Can you explain why "2" is used to balance the equation in the last step of the chemical equation?
    Jerinjames
    Community Answer
    So no extra atoms of any element are added, and so the number of atoms are equal on the left and right sides.
  • Question
    What product is created when marsh gas and oxygen react?
    Community Answer
    Marsh gas contains several chemical components. The primary one is methane. It reacts with oxygen when ignited. There are two products of this reaction, carbon dioxide and water--CH4 + 2 O2 --> CO2 + 2 H2O. Hydrogen sulfide can also be present in marsh gas in minor quantities. When ignited, its reaction with oxygen produces water and sulfur dioxide--2 H2S + 3 O2 --> 2 H2O + 2 SO2. If not ignited, it could react slowly by this equation--2 H2S + O2 --> 2 H2O + 2 S--producing water and sulfur.
  • Question
    What is a balanced equation?
    Community Answer
    A balanced equation is an equation in which the number of atoms in each reacting element is equal to the number of atoms in each product element.
  • Question
    What is the difference between ferric and ferrous?
    Community Answer
    Ferric refers to the iron oxidation state of +3 while ferrous refers to the iron oxidation state of +2.
  • Question
    Why is respiration an exothermic reaction?
    Community Answer
    The release of gas makes it exothermic. Respiration is not just inhalation, but exhalation, too.
  • Question
    What is a saturated bond?
    Community Answer
    Saturated bond is a chemical compound that has a chain of carbon atoms linked together by single bonds.
  • Question
    Is it necessary to change blocks in all types of bonds?
    Community Answer
    Yes, because there are many bonds when dealing with electrons, protons, and neutrons.
  • Question
    How do I find the valency and atomic number of an element (for example Cu2+)?
    Community Answer
    You have to know the atomic number and the electrons present in each shell. For quicker recollection, it will be better to remember the periodic table groupwise and not period wise.
  • Question
    How do I write the equation for Al+HCl?
    Community Answer
    Answer: AlCl3 + H2 ; There are three main steps for writing the net ionic equation for Al + HCl = AlCl3 + H2 (Aluminum + Hydrochloric acid). First, we balance the molecular equation.
  • Question
    What does the = sign signify while writing an equation?
    Community Answer
    It is equivalent to the arrow symbol. You would use it after the reactants and before the products.
  • Question
    How do you form chemical equations?
    I_l1ke_gam3s
    Community Answer
    Make sure that the number of molecules (or atoms) is the same for both the reactants and the products. If there are more atoms or molecules on one side than the other, something went wrong (because matter can't be created or destroyed).
  • Question
    How do I know if an equation is balanced?
    Community Answer
    The equation is balanced if both sides (the reactants and the products) have the same number of molecules and the same number of atoms.
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