HW: Study for the Test Tomorrow HW: Study for the Test Tomorrow!!! Finish your review packet if not done in class. INDEX CARDS= +2pts. Current Events due Friday Do Now: 3/9/16 **ROUND ALL OF YOUR ANSWERS TO THE NEAREST TENTH AND DRAW THE BLOCK IN THE CUP!!!** 1) Find the density of an object that has a mass of 42g and a volume of 8mL. What is the percent under water for this object? 2) Find the density of an object that has a mass of 36g and a volume of 93cm3. What is the percent under water for this object?

SHOW YOUR WORK!! 1) 2)

Matter and Measurement Study Guide Packet Work with the lab partner at your table to complete the Chemistry Study Guide packet.

Anything that has mass and volume. It is what the world is made of. Solid – has definite shape & volume Liquid – has no definite shape but definite volume Gas – has no definite shape or volume Melting – solid to liquid (by adding heat) Freezing – liquid to solid (by removing heat) Evaporating – liquid to gas (by adding heat) Condensation – gas to liquid (by removing heat) The amount of matter in an object

Triple beam balance Grams Measurement of effect of gravity on mass The amount of space an object takes up Ex: block, table, book Regular Method - Measure and calculate LxWxH Volume is measured in centimeters3 (cm3).

Metric ruler is used to measure volume. Ex: pebble, marble, paper clip Water displacement method Graduated cylinder The unit is milliliters (mL). Heaviness of an object, for its size Mass/Volume The unit is g/cm3 or g/mL.

C. Estimate the densities of the blocks below. .5 g/cm3 .9 g/cm3 .3 g/cm3

Characterisitcs used to identify it *could be physical or chemical mass odor volume density Does not create a new substance Cutting, melting, dissolving. Creates a new substance Cooking, rusting, burning.

The density of water is 1. 0 g/mL The density of water is 1.0 g/mL. We use it to compare because it is the universal solvent and is readily available to all scientists Nothing. The density will remain the same because making an object smaller will not change its density.

Suppose you find the mass of a piece of iron metal, leave it out in the rain to rust, and measure the mass again. You find that the mass has INCREASED. Does this violate the law of conservation of matter? Be prepared to defend your answer. Before rusting After rusting

The Answer: The law is not violated Rust is Fe2O3, a combination of iron and oxygen. In order to rust the key has to pull oxygen out of the air and oxygen atoms are not weightless. If you chemically removed the oxygen you'd find that the weight of the iron had returned to it's previous value. No new matter is being made here; it's merely being pulled out of the air and combined with something else to form a solid. The law of conservation of mass is not violated. Before rusting After rusting

Density Practice D= m v

Relative Error Practice Relative error % = measured-actual . 100 actual Calculate the relative error of sample of silver that is measured on the package as mass 10g, but you determined its actual mass is 8g. Relative error % = measured-actual . 100 actual Relative error % = 10g - 8g . 100 8g Relative error % = 2g . 100 8g Relative error % = .25 . 100 = 25%

Tim and Moby Explain: BrainPOP: www.brainpop.com States of Matter Conservation of Matter Measuring Matter Density