As a scuba diver goes deeper underwater, the diver must be aware that the increased pressure affects the human body by increasing the — A body’s temperature B amount of dissolved gases in the body C amount of suspended solids in the body D concentration of minerals in the body 9 Going deeper under water, the gasses of the blood become more condensed and “dissolved”. Coming up too fast, is like shaking a can of coke and then opening up. The body doesn’t like it. It’s called the ‘bends’. Home Back to water

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Over time an open soft drink will lose carbonation (dissolved CO 2 ). Which of these allows the CO 2 to remain in solution the longest? A Reduced air pressure B Exposure to direct sunlight C Increased air currents D Cooler temperatures 39 Carbon dioxide Gas Home Back to water

Which bottle will lose it’s dissolved carbon dioxide to the atmosphere soonest?

The table shows temperature and pressure in four containers holding the same amount of water. According to the table, in which container can the most sodium chloride be dissolved in the water? A Q B R C S D T Rule: With solubility of most salts, temperature is more important than pressure. How does temperature affect solubility? Usually, the warmer, the better. But gases dissolve better at lower temperatures. How does pressure affect solubility? The more pressure (lid on) the better the dissolving of a gas in a liquid. 23 Home Back to water

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In this apparatus, the seawater is an example of a — F strong electrolyte G weak acid H nonelectrolyte J strong base The word “BRIGHT” Means the liquid is A strong electrolyte. 18 Home Back to water

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Salt ions being separated by collisions of water molecules during “dissolving.” Home Back to water

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Bathwater normally has electrolytic behaviors even though distilled water does not. This is because bathwater — F contains isotopes of hydrogen G has been heated H is separated into H+ and OH– ions J contains dissolved minerals 24 Isotopes are elements with different number of neutrons although they have the same number of electrons and protons. Heating water does NOT make the water an electricity carrier. Ions in the water, make water carry electricity. Elements of water are covalently bonded meaning that they resist becoming ions. Some always do, but they do not conduct electricity because they are so attracted to the opposite ion. Home Back to water

Sour Slippery Home Back to water

pH indicators pH paper tells pH numbersLitmus paper tells acid or base Home Back to water

A certain commercial product used for cleaning ovens must be handled with rubber gloves. The product is slippery and turns litmus paper blue. It probably contains — F an acid G a base H a salt J an isotope 34 Home Back to water

Two clear solutions are placed in separate beakers. The first solution has a pH of 4, and the pH of the second solution is unknown. If the two solutions are mixed and the resulting pH is 5, the second solution must have — A fewer suspended solids B a lower temperature C more dissolved salt (NaCl) particles D a higher concentration of OH– ions 33 Home Back to water

Acid pH 4 Base with some –OH’s Home Back to water

Home Back to water Acid + Base becomes Salt + Water

Many pitcher-plant species grow well in soil with a low pH. Soil pH could be decreased by adding a solution of — A carbonic acid B potassium hydroxide C ammonia D sodium chloride Home Back to water

physical and chemical change Home

Which of the following processes is an example of a physical change associated with an oak tree? A Decomposition of bark by bracket fungi B Starches and sugars being broken down during energy production C Water and carbon dioxide being converted to glucose D Evaporation of water from the surfaces of leaves Chemical change Physical change 31 Home

Which of the following is an example of a chemical change? F Ice cracking G Sugar dissolving H Milk souring J Lead melting 22 Physical changes: Getting smaller Dissolving Changing phases…solid,liquid,gas Chemical changes: Bonding partners are changed. Milk sugar + proteins → carbon dioxide + water + other chemicals Home

Which of these changes in rocks is a physical change? A Acid rain damaging marble B Iron in rock combining with oxygen to form hematite C Carbonic acid weathering limestone D An ice wedge shattering a slab of shale 13 Home

Which process in the rock cycle is most likely responsible for moon rocks being converted to lunar soil? A Metamorphism B Weathering C Sedimentation D Volcanism 7 Weathering changes rock to soil on the earth, so it might apply to the moon as well. Reheating of rocks. Home

Which of these describes a pollution-producing process that involves only a physical change? A Coal with a high sulfur content is burned, producing gases that cause acid rain. B Chlorofluorocarbons are released, changing ozone in the upper atmosphere into oxygen. C Hot wastewater is discharged into a lake, lowering oxygen levels in the water. D Nitrogen oxide emissions combine with water vapor, producing nitric acid. 31 Coal + S + Oxygen → CO 2 + SO 3 + H 2 O → H 2 SO 4 NO 2 + H 2 O → HNO 3 O 3 → O 2 + O 1 with the Hot water is added to a river or lake. Warmed Oxygen O 2 bubbles to atmosphere. Decrease in dissolved oxygen causes fish kill. Thermal pollution causes a physical change. Normal environment Home

In the rock cycle, which of these is a chemical change involved with the formation of igneous rocks? F Compression of sediments G Heat loss from lava H Subduction of plates J Formation of minerals 36 May cause a chemical change with pressure. May result from chemical changes. May cause a chemical change with heat/friction. Is the act of elements unbonding and rebonding. Home

density Home

A block of maple wood with a volume of 405 cubic centimeters and a density of 0.67 g/cm3 is sawed in half. The density of the two smaller blocks is now — A one-fourth the original density B one-half the original density C two times the original density D the same as the original density 25 If all these blocks are maple, they all have the same density. Home

A sample of an element has a volume of 78.0 mL and a density of 1.85 g/mL. What is the mass in grams of the sample? Record and bubble in your answer to the nearest tenth on the answer document. 20 Density = mass ÷ volume 1.85 = ? ÷ x 78 = ? grams Home

Which procedure is best to use when determining the density of a rock? F Place the rock in a water-filled beaker and find the height at which the rock floats above the water. G Use a ruler to measure the rock’s dimensions and then find its mass using an analytical balance. H Measure the mass of the rock on a balance and then find the volume of water it displaces in a graduated cylinder. J Place the rock in three liquids with different known densities and observe which liquid the rock floats in. 6 Home

– = Density = mass / volume Density = g / 20.1 mL 60.4 – 40.3 = 20.1

Which of the following objects will float on water? 27 Density greater than “1” sinks. Density less than “1” floats. 45/40 = greater than 1 50/45 = greater than 1 55/50 = greater than 1 60/65 = less than 1 Home

What is the mass of a mL sample of seawater with a density of g/mL? F g G g H g J g 18 Density = mass ÷ volume = ? ÷ x = ? Home

Compared to 250 g of gaseous nitrogen, 250 g of liquid nitrogen has greater — A volume B temperature C mass D density Gases have a greater volume than liquids. Density is mass / volume Gas N 2 Liquid N 2 250/big number 250/small number 35 Home

17 Swimmers find that they can float more easily in the ocean than in a freshwater pond. The most likely reason for this phenomenon is that the — A viscosity of pond water is greater than that of ocean water B density of ocean water is higher than that of pond water C temperature of pond water is lower than that of ocean water D mass of ocean water is greater than that of pond water. Density less than ‘1’ floats on water. Density more than ‘1’ sinks in water. 17 Home

From 1942 to 1945, U.S. nickels were made of an alloy that contained 35% silver, 9.0% manganese, and the rest copper, by mass. If one of these nickels has a mass of 5.0 grams, what is the mass of the copper? A 0.5 g B 1.8 g C 2.2 g D 2.8 g 23 Silver + manganese + copper = 100% Copper = Copper = 56% or 56/100 or.56 ÷ 56 / 100 x 5 grams = 2.8 grams or.56 x 5 = 2.8 Home

What is the density at 20°C of 12.0 milliliters of a liquid that has a mass of 4.05 grams? A g/mL B 2.96 g/mL C 16.1 g/mL D 48.6 g/mL 31 Don’t need temp. Density = mass ÷ volume ? = 4.05 g ÷ 12mL Home

This pipette is filled with a 20% NaOH solution. The solution is at 20°C and has a density of 1.23 g/mL. According to this information, what is the mass of this NaOH solution? A 3.88 g B 15.7 g C 23.9 g D 24.6 g 27 D = m ÷ V D x V = m 1.23 x amount in graduated cylinder = mass Home