Physical and Chemical Changes Essay

1. Record your hypothesis about what will happen when Biuret solution is mixed with the solutions from test tubes 1, 2, 3, and 4 here. Be sure to use scientific reasoning to support your hypothesis.

Measure the mass and calculate the density of the magnet using the correct significant figures and units. Show work for full credit. (2 points)

a. Credit will only be given if you clearly show your work, and clearly indicate the final answer.

3. Carefully felt the sides of the test tube and observed the resulted chemical reaction for about 30 seconds.

3. 3.14 x 1023 molecules of CO2 are produced in a chemical reaction. How much would the sample weigh in grams?

b) In order to calculate the mean or average for the governors and CEO’s, I added together all the figures and divided that sum by 4 since there

13. Calculate the change in temperature for the water caused by the addition of the aluminum by subtracting the initial temperature of the water from the

Weight 10 dry post-82 pennies which get 77.12g, using 30ml initial volume measuring the volume of 10 pennies, record the data 9.1ml. Using equation Density= Mass/Volume, get the density of the pre-82 pennies is 8.47g/ml. Then calculate the error%=0.04%, and the deviation%=7.13%.

a. It should be split between the right and left tails, with .05 appearing in each tail.

Substances A and B have an appearance of a white solid like. Substances A and B were put into a test tube and on the Bunsen burner. As a result, B melted faster than A. A was slow to melt. The reason why B melted faster than A is because it has a lower boiling point than substance A which made it melt faster. It also shows that A needs more energy than B to be broken down.

5. A salvage operator recovered coins believed to be gold. A sample weighed 129.6 g and had a

Seven various household objects were chosen to measure using a digital gram scale. Each object’s mass was estimated by lab students and recorded in data table 4. A quarter, ball point pen, rubber bulb, large paper clip, green crayon, house key and a copper penny masses were estimated and recorded in data table 4. Each object was placed on the scale individually and its actual measurement was recorded in data table 4. As we started estimating the household objects we were often not correct in our estimations. As we measured more and more objects, we got better in our estimations by comparing objects with known masses and comparing them with the unknown

Changes in matter occur every day. There are two types of ways matter can be altered; physically and chemically. Physical changes do not change the composition of the matter while chemical changes occur when one or more substances turn into a completely new substance.

If you are given a measurement of 4g and a measurement of 4.0001g, you would understand that the equipment used to measure 4.0001g is much more precise than the equipment used to measure 4g. Although significant figures tell us about the precision of the measurement, we really cannot attest to the accuracy of the measurement unless we are sure of the correct answer. The same rule about the estimated digit is applied when taking measurement. The way to report an analog measurement is to write down all the digits you are “confident” in and estimate one digit further. For example, if using a 10ml graduated cylinder with nine markings in between the numbers 1ml and 2ml and the liquid falls between 1.5ml and 1.6ml, but closer to 1.5ml, the digits you are confident in are 1 and 5. Therefore you estimate another digit which you think it could be such as 1.53ml. When making a digital measurement, the rule is to always write down every digit while understanding that the last digit is an estimation. There are also a few important differences between the course policy and the textbook. One is that the book states that if you place a decimal to the right of trailing zeroes, it would make those zeroes significant e.g. 500. has 3 significant figures while 500 has 1. This is not true and they should be ashamed. Another difference is in the convention of marking significant figures. In this course, Professor Halpin will underline all significant figures to identify them. It just makes it easier to get the correct answer while rounding to the correct number of significant figures. The book does not do

After that, it is crucial to convert the mass to volume. The water density at a temperature will aid this process. The compliance of the Volume Occupied by 1.000g of Water Weigh in Air table is deemed necessary throughout the comparison.