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# Significant Figures

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A) Provide the type of measurement (volume, length, temperature etc.) for the following units:

i) 298 K
ii) 65 mL
iii) 15 m
iv) 290 kg
v) 50 g

b) Write the following measurements in scientific notation:
i) 150000000 kg
ii) 0.28 L
iii) 0.00004 m

c) Answer whether the numbers in each of the following statements is measured or exact:
i) The Cambrian explosion occurred 545000000 years ago.
ii) 26 students went for the field trip.
iii) The number of microbes on a telephone is 25600.

d) State how many significant figures there are in each of the following measured quantities:
i) 18.000 m
ii) 52.80 L
iii) 7.0 X 10-14 kg

e) Round off each of the following numbers to two significant figures:
i) 66.666
ii) 0.0063424
iii) 9577

https://brainmass.com/chemistry/general-chemistry/significant-figures-111306

#### Solution Preview

Solution is below, and as HTML attached - provided a couple of links that are live in the HTML page version.

As for "help", I am going to point you to the resources you need to answer these yourself, and put in an example or two - but NOT to do them for you, OK? So let's go then!
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a) Provide the type of measurement (volume, length, temperature etc.) for the following units:

i) 298 K
ii) 65 mL
iii) 15 m
iv) 290 kg
v) 50 g

go to the following site and look at the entries for metric and SI units, should be easy enough
http://www.ex.ac.uk/cimt/dictunit/dictunit.htm#SI

b) Write the following measurements in scientific notation:

i) ...

#### Solution Summary

Answer goes down a sort list of problems and deals with issues such as significant figures, rounding, and math as related to science in general.

\$2.19

## Density, Conversions and Significant Figures

1. a: A cube of osmium metal 1.500cm on a side has a mass of 76.31 g at 25*C. What is its density in g / cm3 at this temperature?

B: The density of titanium metal is 4.51 g / m3 at 25*C. What mass of titanium displaces 65.8 mL of water at 25*?

C: The density of bezene at 15 *C is 0.8787 g / mL. Calculate the mass of 0.1500 L of benzene at this temperature.

Solutions for a,b,c

A. g/cm3
B. g
C. g

2, A cylindrical rod formed from silicon is 16.8 cm long and has a mass of 2.17 kg. The density of silicon is 2.33 g / cm3. What is the diameter of the cylinder? (the volume of a cylinder is given by TTr2h, where r is the radius and h is its length.)

Solution:

_________________________________________cm

Question 3: Indicate the number of significant figures in each of the following measure quanties.

A: 3.7745km___________________________
B: 205 m2 ___________________________
C: 1.700cm____________________________
D: 350.0 K _____________________________
E: 307.080 g ___________________________

Question 4. Carry out the following conversions
A: 0.105 in_______________________________mm
B: 0.870 qt_______________________________mL
C: 9.75 um/s______________________________km/hr
D: 4.733 yd3_______________________________m3
E: \$3.99/lb_________________________________dollars per kg
F 8.75 lb/ft3_________________________________g/ml

Solutions

5. Carry out the following operations and express the answer with the appropriate number of signigicant figures.

A: 320.55 - (6104.5/2.3)

B: [(285.3 x 105) - (1.200) x 103] x 2.8954

C: (0.0045 x 20, 000.0) + (2813 x 12)

D: 863 x [1255 - (3.45 x 108)]

6.The concentration of carbon monoxide in an urban apartment is 48 ug/m3. What mass of a carbon monoxide in grams is present in a room measuring 9.0 x 14.5 x 18.8ft?

Solution

______

_________________________________g

7. By using estimation techniques determine which of the following is the heaviest and which is the lightest.

Quantity Conversion factor(s) Conversion to grams

5-lb bag of potatoes g potatoes
5-kg bag of sugar g sugar
1 gal of water (density = 1.0g/ml) g water

Solution

8.The liquid substances mercury (density = 13.5 g / mL), water (1.00 g / ml ), and cyclohexane
(0.778 g / mL) don not form a solution when mixed, but separate in distinct layers. Sketch how the liquids would position themselves in a test tude.

Question 9. Small spheres of equal mass are made of lead (density = 11.3 g / m3),
Silver (10.5 g / m3) and aluminum (2.70 g / m3). Which sphere has the largest diameter and which has the smallest?

Spheres: