Fun with science
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The document discusses the properties of water including: its chemical composition of H2O, that it can exist in solid, liquid, and gas forms, and that density is related to the number of atoms in a substance. It describes an experiment where salt and sugar are added to water to test the hypothesis that this will make the water more dense. The results showed that salt water was denser than sugar water or pure water. The document also provides some additional facts about water and acid-base reactions.
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Fun with science
- 1. Cam-Tu Diep
- 2. ~Around 2/3 to ¾ of the earth surface is cover with water. ~Did you know that our bodies are made up of 65% water. ~75-80% of the human brain is water. ~The chemical name for water is H(2)O - which represents two Hydrogen atoms and one Oxygen atom.
- 3. 1) Solid - frost , snow, ice. 2) Liquid – water, rain. 3) Gas - water vapour.
- 4. Density is mass (how many atoms are in an object) divided by volume. The more atoms a liquid contains the denser it will be.
- 6. Regular Water Salt Water => Water + Salt Sugar water => Water + Sugar Question & hypothesis: Will adding salt make water more dense? Will adding sugar make water more dense? Which is denser, sugar water or salt water? Write down what you think will happen to the density of water if you add salt or sugar. *Hypothesis: is a proposed explanation for a phenomenon.
- 7. Fill three beakers with 150 ml (2/3 cup) of water. Add food coloring to make blue, red, and green water. Add 2 teaspoons of salt to the blue beaker and stir until the salt is dissolved. Add 2 teaspoons of sugar to the yellow water and stir until it is dissolved. Try putting a raisin in each of the beakers. Does it float? Remove the raisins with a spoon. Pour some of the blue (salty) water into the graduated cylinder. Using the pipet, slowly add the yellow (sugar) water one or two drops at a time. Record which sinks to the bottom and which floats on top. Add the red (pure) water drop-by-drop to the other two and record what happens.
- 9. Were your predictions correct? Did adding salt and sugar to the water make the water more dense or less dense? Which was more dense, the salt water or the sugar water?
- 10. Water Facts and Trivia
- 11. H+ (aq) + OH− (aq) H2O acid + base → salt + water CH3CO2H + NaHCO3 => CH3CO2Na +H2O+CO2 (formed from unstable carbonic acid H2CO3) Vinegar + baking soda =>Sodium acetate +water + carbon dioxide Sodium bicarbonate and vinegar => Sodium acetate and water and carbon dioxide NaHCO3 + CH3COOH => CH3COO-Na+ + H2O + CO2 The positive ion from a base forms a salt with the negative ion from an acid.
- 12. Baking soda is made of sodium bicarbonate. Vinegar is an acid (acetic acid). When the two combine, they create a chemical reaction (Acid-base Reaction). Vinegar causes the baking soda to break down, creating a different substance. This gas is called carbon dioxide. It is less dense than the air around it. The carbon dioxide rises into the balloon, inflating it.
Editor's Notes
- The atom is a basic unit of matter that consists o a dense central nucleus surrounded by a cloud of negatively charged electrons.
- saltwater is more dense because the molecules are closer together
- H2CO3:carbonic acid is unstable so it falls apart into carbon dioxide and water.http://www.chemicalformula.org/baking-sodaSodium acetate – a sodium salt.FoodSodium acetate may be added to foods as a seasoning. It may be used in the form of sodium diacetate — a 1:1 complex of sodium acetate and acetic acid,[3] given the E-numberE262. A frequent use of this form is in salt and vinegar chips in the United States. Many US brands, including national manufacturer Frito-Lay, sell "salt and vinegar flavoured" chips that use this chemical, with lactose and smaller percentages of other chemicals, in lieu of a real salt and vinegar preparation.[4]
- What actually happens is this: the acetic acid (that's what makes vinegar sour) reacts with sodium bicarbonate (a compound that's in baking soda) to form carbonic acid. It's really a double replacement reaction. Carbonic acid is unstable, and it immediately falls apart into carbon dioxide and water (it's a decomposition reaction). The bubbles you see from the reaction come from the carbon dioxide escaping the solution that is left. Carbon dioxide is heavier than air, so, it flows almost like water when it overflows the container. It is a gas that you exhale (though in small amounts), because it is a product of the reactions that keep your body going. What's left is a dilute solution of sodium acetate in water.