TAKS Objective 4: Structure & Properties of Matter

Chemical & Physical Properties Chemical –The ability or inability of matter to chemically react with other matter Physical –Measurable –Observable by our 5 senses

Cylinder Activity Identify the material in each of the cylinder as element, compound, or mixture. Iron Nails Cotton Balls Pure Canola Oil Styro- foam Air Glass Marbles Pure Water Recycled Tires Cotton Balls

Classifying Matter Element –Contains one type of atom, found on periodic table Compound –2 or more elements chemically combined. Chemical formula. Mixture –elements and/or compounds that are physically combined and different materials are visible. –Solutions are homogenous mixtures H2OH2O

Cylinder Activity Arrange the cylinders from least to greatest volume. What evidence did you use to determine your arrangement?

Cylinder Activity Arrange the cylinders from least to greatest mass. What evidence did you use to determine your arrangement ?

Cylinder Activity Arrange the cylinders from least to greatest density. What evidence did you use to determine your arrangement?

Mass, Volume, and Density V A __ V B M A __ M B D A __ D B A B < < =

A Quick Density Review ratio of mass to volumeratio of mass to volume high density: a lot of mass in a small volumehigh density: a lot of mass in a small volume Density of water is 1 g/mLDensity of water is 1 g/mL Density = mass = m volume vDensity = mass = m volume v

Evaluating Density Compare the mass, volume and density of sample A and B below.Compare the mass, volume and density of sample A and B below. What would happen to the density of B if the sample were cut in half?What would happen to the density of B if the sample were cut in half?

A block of maple wood with a volume of 405 cubic centimeters and a density of 0.67g/cm 3 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

Evaluating Density How does the density of the Diet Coke compare to that of the Coke? Explain. If the density of water is 1 g/mL, then what can you infer about the density of each can of soda?

The table shows some properties of four different substances. The picture shows a solid sphere of one of the four substances in a water- ethanol solution (D = g/mL). The sphere is most likely composed of which substance? A Substance Q B Substance R C Substance S D Substance T D = g/mL

The instruments below show the mass and volume difference of an irregularly shaped object. Using the data, the density of the object is ____________. A 25.4 g/mL B 4.40 g/mL C g/mL D 5.24 g/mL

Answer Explanation Recall, Density = Mass/Volume Here, the mass is shown on the balance as 22 g. The volume of the irregular-shaped object must be found by using the water displacement method. The initial volume of water reads 20.0 mL and the final volume of water reads 25.0 mL. Subtract the final volume by the initial volume to determine the volume of the object, 5.0 mL. D = M/V = 22 g/5.0 mL = 4.40 g/mL. Therefore, answer choice B is correct.

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

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? 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 D =m 1.23 g = _m_ 1 v 1 mL 19.4 mL m=1.23g x 19.4mL = 23.9 g 1 mL Answer is C

Two scientists decided to compare the densities of a crown and a block of metal. The scientists found the volume of the block and computed its density based on its known mass (2,400 g). The diagram below shows the dimensions of the block of metal that the scientists measured. What is the density of the block of metal? Answer: ____________ g/cm3

Answer Explanation D = M/V The mass is given in the problem; M = 2400 g. To determine the volume of the box: V = length x width x height V = 5 cm x 5 cm x 5 cm = 125 cm 3 D = 2400 g/125 cm 3 = 19.2 g/cm 3

Chemical vs. Physical Changes Sort the items in your envelope into physical and chemical changes. Be prepared to discuss your classifications. You have 6 minutes.

Chemical vs. Physical Changes  Chemical Change –Atoms chemically combine in a new way –Represented by a chemical reaction –Observations: Color changeColor change Temperature changeTemperature change Gas producedGas produced Solid formedSolid formed  Physical Change –Same combination of atoms –Observations:  Change in shape, size or location  Change in phase

Ratios in Chemical Formulas A chemical formula is a combination of element symbols and subscripts that tells you the ratio of elements. (Lab- Aids Inc.) Examples: H 2 O = 2 atoms H to 1 atom O 2 H : 1 O Fe 2 O 3 = 2 atoms Fe to 3 atoms of O 2 Fe : 3 O *NaCl = 1 atom Na to 1 atom Cl 1 Na : 1 Cl *For NaCl, the ratio is 1:1 because Na is a Group 1 element with 1 valence electron (loses 1e-) and Cl is a Group 17 element with 7 valence electrons (gains 1e-).

The ionic compounds that results from combining Group 2 and Group 16 elements have a 1:1 ratio because— A Group 2 elements are electrically neutral. B Group 2 elements have two valence electrons. C Group 2 elements contain neutrons in the nucleus. D Group 2 contains more elements than other groups.

Elements from Group 1 on the Periodic Table will form compounds with elements from Group 15. An example would be potassium phosphide (K 3 P). A compound with elements from these two groups will always combine with a ratio of __Group 1 : __Group 15. A 6 : 2 B 2 : 6 C 1 : 3 D 3 : 1

Conservation of Mass chemical reaction Both sides of a chemical reaction must have the same mass: mass reactants = mass products. This is the Law of the Conservation of Mass – Matter is neither created nor destroyed. 2Hg + O 2 2HgO 10g 9.3g + ? 0.7g Oxygen became a gas 10 g = g...But what happened to the O 2 ?

According to the law of conservation of mass, how much zinc was present in the zinc carbonate? A 408 g B 256 g C 104 g D 40 g

Is mass conserved? H2 + O2H2 + O2H2 + O2H2 + O2 H2OH2OH2OH2O What do we need to do?

2H 2 + O 2 2H 2 O Reactants: 4 H 2 O Products: 4 H 2 O To be balanced, there must be the same number of atoms of each element on both sides of the equation.

Using Particles to Balance Chemical Equations __H 2 +__O 2  __H 2 O Step 1: Place or draw one of each particle under its symbol on your hand-out. Step 2: Count number of each kind of atom on both sides of the equation. Step 3: Add complete particles to each side until the number of atoms balances. Step 4: Write in the correct number for each coefficient.

Your turn… Continue using the particles or drawings to balance the remaining equations. Remember: –First sort the paper clips into piles according to # and colors of beads. –Using the particles provided, balance the equations on the following slide. –You must have the same # and color of paper clips on both sides of the equation.

Using the beads, practice balancing the following chemical equations. __Al + __O 2  __Al 2 O 3 __Al + __O 2  __Al 2 O 3 __C 2 H 4 + __O 2  __CO 2 + __H 2 O __C 2 H 4 + __O 2  __CO 2 + __H 2 O __Zn(NO 3 ) 2 + __Na 2 CO 3 __ZnCO 3 + __NaNO 3 __Zn(NO 3 ) 2 + __Na 2 CO 3  __ZnCO 3 + __NaNO 3

Place the beads back in their storage container. Continue balancing the following chemical equations by counting and drawing atoms as you will have to do on the TAKS test. __PbO 2  __PbO + __O 2 __K + __H 2 O  __KOH + __H 2

Good Luck! Make good use of your periodic table and formula chart!Make good use of your periodic table and formula chart! Get a good night sleep.Get a good night sleep. Study the night before, your brain will continue to process while you sleep.Study the night before, your brain will continue to process while you sleep.