replacement reactions

single replacement reactions

A single replacement reaction occurs when one element replaces another in a single compound. This type of reaction has the general equation: A + BC B + AC In this equation, A represents a more reactive element and BC represents the original compound. During the reaction, A replaces B, forming the product compound AC and releasing the less reactive element B. An example of a single replacement reaction occurs when potassium (K) reacts with water (H2 O). A colorless solid compound named potassium hydroxide (KOH) forms, and hydrogen gas (H2 ) is set free. The equation for the reaction is: 2K + 2H2 O 2KOH + H2 In this reaction, a potassium ion replaces one of the hydrogen atoms in each molecule of water. Potassium is a highly reactive group 1 alkali metal, so its reaction with water is explosive. Q: Find potassium in the periodic table of the elements. What other element might replace hydrogen in water in a similar replacement reaction? A: Another group 1 element, such as lithium or sodium, might be involved in a similar replacement reaction with water.

what is a replacement reaction

A replacement reaction occurs when elements switch places in compounds. This type of reaction involves ions (electrically charged versions of atoms) and ionic compounds. These are compounds in which positive ions of a metal and negative ions of a nonmetal are held together by ionic bonds. Generally, a more reactive element replaces an element that is less reactive, and the less reactive element is set free from the compound. There are two types of replacement reactions: single and double. Both types are described below. Q: Can you predict how single and double replacement reactions differ? A: One way they differ is that a single replacement reaction involves one reactant compound, whereas a double replacement reaction involves two reactant compounds. Keep reading to learn more about these two types of reactions.

double replacement reactions

A double replacement reaction occurs when two ionic compounds exchange ions. This produces two new ionic compounds. A double replacement reaction can be represented by the general equation: AB + CD AD + CB AB and CD are the two reactant compounds, and AD and CB are the two product compounds that result from the reaction. During the reaction, the ions B and D change places. Q: Could the product compounds be DA and BC? A: No, they could not. In an ionic compound, the positive metal ion is always written first, followed by the negative nonmetal ion. Therefore, A and C must always come first, followed by D or B. An example of a double replacement reaction is sodium chloride (NaCl) reacting with silver fluoride (AgF). This reaction is represented by the equation: NaCl + AgF NaF + AgCl During the reaction, chloride and fluoride ions change places, so two new compounds are formed in the products: sodium fluoride (NaF) and silver chloride (AgCl). Q: When iron sulfide (FeS) and hydrogen chloride (HCl) react together, a double replacement reaction occurs. What are the products of this reaction? What is the chemical equation for this reaction? A: The products of the reaction are iron chloride (FeCl2 ) and hydrogen sulfide (H2 S). The chemical equation for this reaction is: FeS + 2HCl H2 S + FeCl2

instructional diagrams

No diagram descriptions associated with this lesson

questions

less reactive elements replace more reactive elements in compounds.

a. true

-->  b. false

replacement reactions always involve ionic compounds.

-->  a. true

b. false

a single replacement reaction always involves two reactant compounds.

a. true

-->  b. false

which of the following is a single replacement reaction?

a) fes + 2hcl  h2s + fecl2

-->  b) fe + cuso4  feso4 + cu

c) agno3 + nacl ---> agcl + nano3

d) none of the above

the general equation for a double replacement reaction is

a) ab + cd  bc + da.

b) ab + c + d  ad + cb

c) ab + c  ac + b

-->  d) none of the above

a compound in a replacement reaction always consists of

a) a positive ion and a negative ion.

b) a metal ion and a nonmetal ion.

c) two negative metal ions.

-->  d) two of the above

diagram questions

No diagram questions associated with this lesson