Unit+1--Matter+and+Measurement

Unit 1 3 and 4.

5. Phase Changes 6. The uncertainty of measurements is the physical value over true value. Its like the rounded number in a measurement and depends on the type of tool you use to measure it. Example: You measure a football on a scale and it comes out to be 1.4 grams. Then you measure it on a triple beam balance and its 1.383 grams. The uncertainty value would be 1.4 grams. 7.Contrast accuracy and precision. Accuracy is correctness. It is checked by using different methods. Having poor accuracy results from equipment flaws and its is associated with systematic errors. Precision ties into reproducibility or getting consistent results from a specific procedure. With precision poor results come about with a bad technique. Precision is associated with random errors. 8. Practice conversions.
 * Phase Change || Energy Change (Absorbed or lost) || Decription of Change ||
 * Melting || Energy absorbed by ice || Solid to Liquid ||
 * Freezing || Energy lost by ice || Liquid to Solid ||
 * Evaporation || Energy absrobed by water surface || Liquid to Gas ||
 * Condensation || Energy lost from clouds || Gas to Liquid ||
 * Deposition || Energy absorbed by gas || Gas to Solid ||
 * Sublimation || Energy lost from solid || Solid to Gas ||

9. Solve the following density problems. A. What is the volume of a tank that can hold 18,754 Kg of methanol whose density is 0.788 g/cm3? B. What is the density of a board whose dimensions are 5.54 cm X 10.6 cm X 199 cm and whose mass is 28.6 kg? C. CaCl2 is used as a de-icer on roads in the winter. It has a density of 2.50 g/cm3. What is the mass of 15.0 L of this substance? D. In the Macy’s Thanksgiving’s day parade, 2000, there was a new float, the Cheerios’ bee, Buzzbee. The jar of honey it was holding contained 36,768 L of helium. The honey jar was 1/10 of the body size. What is the volume of the entire float? If the density of helium is 0.000178 g/cm3, what is the mass of the helium for the entire float in kg?

The enitre mass of the float is 471538.5 Kg.