Question

Just briefly explain number 2.

what happened chemically

Part 2. An acid is a compound that releases hydrogen ions (H+) when dissolved in water, creating an acidic solution. An alkaline or base is a compound that releases hydroxide ions (OF when dissolved in water, creating an alkaline or basic solution. Both hydrogen ions and hydroxide ions are present in water because water molecules dissociate and reform, and dissolved substances add or remove ions. pH is the measure of how much H+ is concentrated in solution. On the pH scale, 7 is neutral, higher numbers are more basic, and lower numbers are more acidic. The pH scale is not linear: this means that a small increase or decrease in pH corresponds to a 10-fold increase or decrease in H+ concentrations. Ocean water contains dissolved substances that make it slightly alkaline, so its average pH is 8.1. Adding certain dissolved gases, such as carbon dioxide, can increase the number of H+ ions in solution, makin the water more acidic. This is described by the following chemical formula: H20+CO2 → H2CO3 → H+ HCO3 1. You have two samples of water at your lab bench. Use the pH indicator strips to answer the following questions. What is the pH value of each sample? How can you tell which one is seawater? 2. Blow into the sea water for 2 min through the straw. Measure the pH again. What is the pH now? Briefly explain what happened chemically to induce this change.

Answer 1

Answeg - You are provided with use pH strips to showed Dip the pH strips in tested. Then compare the the color indicator chart two samples of water cue can the pH of the sample. to the sample of cuater to be reading of the pH by comparing given with the pH test kit. For pure cuates H = 7 neuteal to 8.5 For sea water = 7.5 (slightly alkaline) pH above 7 cue can conclude If the sample that it is sea pH scale o1 2 3 shows water. 4 5 6 7 8 9 10 11 12 13 14 acidic neutral Basic 2 when you blow in to the air can dissolve cuater. water in the the coa water present in and it then our exchaled react with H₂O + CO2 = H₂CO₃ cuater cambon carbonic acid. dioride насоз (4) = 1 + Hсоз а) The carbon dioxide cue exchaled react with cuater in small amounts to foem carbonic acid H₂CO₃). so the pH of the wated changes. It shows reading less than 7. So the water become slightly acidic. Scanned with CamScanner