1. A piece of metal was weighed on a laboratory balance five times and gave the following values: 15.75, 15.73, 15.77, 15.76and 15.74 grams.Determine the average mass andstandard deviation from the mean mass.(b) An object weighs 0.0930 gramson an analyticalbalance. Indicate theaccuracy of the balance and the number of significant figures in this weight.

1. A piece of metal was weighed on a laboratory balance five times and gave the following values: 15.75, 15.73, 15.77, 15.76and 15.74 grams.Determine the average mass andstandard deviation from the mean mass.(b) An object weighs 0.0930 gramson an analyticalbalance. Indicate theaccuracy of the balance and the number of significant figures in this weight.

Principles of Modern Chemistry

8th Edition

ISBN:9781305079113

Author:David W. Oxtoby, H. Pat Gillis, Laurie J. Butler

Publisher:David W. Oxtoby, H. Pat Gillis, Laurie J. Butler

ChapterA: Scientific Notation And Experimental Error

Section: Chapter Questions

Problem 10P

See similar textbooks

Similar questions

1) Perform the indicated mathematical operations. State the uncertainty of the final answer as ± 1-digit variation in the least significant digit. (remember that the last significant digit's place holder is the most uncertain digit!) 7.700 x 2.1 = uncertainty: 2.132 + 17 + 4.04 = uncertainty: 27000 + 500 = uncertainty: 30.0 x 50.0 = uncertainty: (9.6 × 107)(1.24 × 10³)_ uncertainty: 1.897 x 102
Report all numerical answers to the correct number of significant figures! (a) Give the names of the following elements: (i) Ag (ii) V (b) Give the symbols of the following elements: (i) aluminum (ii) copper 1. 2. Report the answers of these calculations to the correct number of significant figures: (a) 3.7793 x 8.324 x 7.4976 = ? (b) 10.4071 +66.1441 +12.515 = ? (c) (7.971 x 10¹7) (3.75 x 10³)/7.8416 = ? (Report answer in exponential notation.)
Suppose a student measured the mass of a sample that has a known mass of 40.5809 g using an analytical balance. The mass they observed was unstable, constantly jumping between 39.5 and 41.5. Choose all of the following reasons that could cause this error. O The doors to the analytical balance were not closed completely, allowing an air current to circulate inside the balance. One weigh boat was used to tare the balance while a different one was used when the sample was massed. Twice the amount of sample was placed on the analytical balance. O The sample was heated, causing a convective flow.
A garage manager must determine the number of metal ball bearings (BBs) in a stock container by mass measurements. He counts out 5 BBs and finds their total mass to be 1.9 g. He also finds the total mass of the stock container and the BBs to be 239.3 g and the mass of an identical, empty stock container to be 115.8 g. The store manager then uses his data to calculate the number of BBs in the stock container: Average mass of one BB = 1.9/5 = 0.4 g Mass of BBs in container = 239.3 g - 115.8 g = 123.50 g Number of BBs in container = 123.50/0.4 g= 300 BBs (a) Evaluate the manager’s calculations with regard to significant digits. If necessary, rewrite any steps, recalculating with the adjusted quantities. For any step that you have to rewrite, explain why the manager’s calculation is in error. (b) Should the manager regard the answer to the calculation in (a) as a perfect measure of the number of ball bearings in the container? (c) How could the manager have changed his procedure to…
A barometer is filled with a cylindrical column of mercury that is 76.0 cm high and 1.000 cm in diameter. If the density of mercury is 13.53 g/cm3, what is the mass of mercury in the column? Express the answer in standard notation using the correct number of sig. figs.
Calculate (a) the density of a solid substance if a cube measuring 2.33 cm on one side has amass of 117 g and (b) the mass of a cube of the same substance measuring 7.41 cm on one side.
The pharmacist attempts to weigh 0.375 g o morphine sulfate on a balance of dubious accuracy. When checked on a highly accurate balance, the weight is found to be 0.400 g. Calculate the percentage of error in the first weighing.
The mass of an iron nail is measured before and after being placed in a beaker of water for 2 days. It is found that 0.059 g of iron (3) oxide (rust) was produced over the 2-day period. What mass of iron in the nail reacted with the water? Assume the nail is pure iron
Express the results of the following additions and subtractions to the proper number of significant figures. All of thenumbers are measured quantities.(a) 245.876+ 4.65+ 0.3678 =(b) 798.36 - 1005.7 + 129.652 =(c) 7.98 × 1017 + 6.472 × 1019 =(d) (4.32 × 10-15) - (6.257 × 10-14) - (2.136 × 10-13) =
2. Report the answers of these calculations to the correct number of significant figures: (a) 5.354 x 4.812 x 6.8312 = ? (b) 29.4464 + 10.395 +5.20853= ? (c) (5.7268 x 10¹) (6.9 x 10¹0)/1.0= ? (Report answer in exponential notation.)
(a) Read the following description of the element zinc andindicate which are physical properties and which are chemicalproperties. Zinc melts at 420 °C. When zinc granules are added to dilutesulfuric acid, hydrogen is given off and the metal dissolves.Zinc has a hardness on the Mohs scale of 2.5 and a density of7.13 g>cm3 at 25 °C. It reacts slowly with oxygen gas at elevatedtemperatures to form zinc oxide, ZnO. (b) Which properties of zinc can you describe from thephoto? Are these physical or chemical properties?
(a) Read the following description of the element zinc andindicate which are physical properties and which are chemicalproperties.Zinc melts at 420 °C. When zinc granules are added to dilutesulfuric acid, hydrogen is given off and the metal dissolves.Zinc has a hardness on the Mohs scale of 2.5 and a density of7.13 g>cm3 at 25 °C. It reacts slowly with oxygen gas at elevatedtemperatures to form zinc oxide, ZnO.