Do Now A clear liquid is heated in a beaker. At a temperature of 195 degrees Celsius, the clear liquid begins to evaporate and has a strong odor. After 5 minutes, the clear liquid is removed from the hot plate and is allowed to cool at room temperature. A second clear, aqueous solution is also at room temperature. Fifteen mL of the second clear, aqueous solution is added to the first beaker. When the solutions are mixed, a white solid forms at the bottom of the beaker. 1.In the scenario above, identify the evidence that a chemical change occurred. 2.The clear liquid boiling at 195 degrees Celsius is an example of a: a.Physical property b.Chemical property c.Physical change d.Chemical change

SOLUBILITY AND PRECIPITATION REACTIONS Double Replacement!

By the end of today’s class I will be able to… ◦Identify precipitation reactions ◦Predict the products of a precipitation reaction by using a solubility chart

CHEMICAL REACTIONS PrecipitationAcid Base Redox

Precipitate ◦Precipitate – the solid that forms when two aqueous solutions react ◦The solid is considered to be insoluble

What is solubility? Solubility: the extent to which a substance dissolves in another substance In your own words, how would you define the terms soluble and insoluble?

NaCl & CaCO 3 in water

Soluble (dissolves)Insoluble (doesn’t dissolve) -or Slightly Soluble

Solubility Rules – can be used to predict solubility & state of matter Is NaCl soluble?

Solubility Rules – can be used to predict solubility & state of matter Is CaCO 3 soluble? Is Ca(OH) 2 soluble? Is AgBr soluble?

◦First by yourself, you will identify the compound as soluble or insoluble (30 seconds) ◦Then, you will have an opportunity to discuss your answer with your partners (30 seconds) ◦Come to a consensus and write your final answer on the whiteboard

QuestionCompound Soluble or Insoluble? 1HgBr 2 Insoluble 2AgNO 3 Soluble 3Fe(OH) 3 Insoluble 4Fe(NO 3 ) 3 Soluble 5KOH Soluble

When can we use Precipitation Reactions in real life? ◦Test for lead in drinking water

Precipitation Reaction ◦two aqueous solutions react and a solid (insoluble) product is formed. aka: Precipitate!!

Precipitation =Double Replacement AgNO 3 (aq) + KCl(aq)  ______ + ________ Ag + + NO K + + Cl -  AgCl(s) + KNO 3 (aq)

How to predict products of a double replacement reaction: 1. Circle the positive ions and underline the negative ions in your reactants ___KOH(aq) + ___Fe(NO 3 ) 3 (aq)  ______ + ______

How to predict products of a double replacement reaction: 2. Write the charges for each of the ions in the reactants ___KOH(aq) + ___Fe(NO 3 ) 3 (aq)  ______ + ______ +1 +3

How to predict products of a double replacement reaction: 3. Write the positive ions into the products with charges ___KOH(aq) + ___Fe(NO 3 ) 3 (aq)  K______ + Fe____ +1 +3

How to predict products of a double replacement reaction: 4. ‘Switch dates’ (ie: write the negative ions next to the positive with charges) ___KOH(aq) + ___Fe(NO 3 ) 3 (aq)  K NO 3 + Fe OH +1 +3

How to predict products of a double replacement reaction: 5. Balance each compound by Criss- Crossing charges to determine number of atoms ___KOH(aq) + ___Fe(NO 3 ) 3(aq)  K (NO 3 ) + Fe (OH) 3

How to predict products of a double replacement reaction: 6. Balance the equation using coefficients ___KOH(aq) + ___Fe(NO 3 ) 3 (aq)  __KNO 3 + __Fe(OH) 3 3 3

How to predict products of a double replacement reaction: 7. Determine states of matter using the solubility chart ___KOH(aq) + ___Fe(NO 3 ) 3 (aq)  __KNO 3 (aq) + __Fe(OH) 3 (s) 3 3

◦Each team starts with the points earned from Power 5 ◦A correct answer is worth 1 point ◦Points can be wagered on the “horse race” ◦Team with the most points at the end of 3 questions wins

Question 1 Predict the products of the following reaction to decide if the following reaction is a precipitation reaction. If so, circle the precipitate. _BaCl 2 (aq) + _Na 2 SO 4 (aq)  _____ + _____

Question 2 Predict the products of the following reaction to decide if the following reaction is a precipitation reaction. If so, circle the precipitate. _CuSO 4 (aq) + _Na I (aq)  _____ + _____

Question 3 Predict the products of the following reaction to decide if the following reaction is a precipitation reaction. If so, circle the precipitate. _Na I (aq) + _Pb(NO 3 ) 2 (aq)  _____ + _____

Question 4 Predict the products of the following reaction to decide if the following reaction is a precipitation reaction. If so, circle the precipitate. _Pb(NO 3 ) 2 (aq) + _ CuSO 4 (aq)  ____ + ___

Closing Traits affect the formation of precipitation reactions! ◦How do you determine the solubility of a compound? ◦What are the steps taken to predict the products of a precipitation reaction?

Exit Ticket Write whether the following compounds are soluble or insoluble: 1.K 3 PO 4 2.Cu(OH) 2 3.Write the products for the following reaction. Be sure your final equation is balanced and that you have written the state of matter of each product. ____CuCl 2 (aq) + ____Na 3 PO 4 (aq) 