When are Digits Significant?
Non-zero digits are always significant. Thus, 22 has two significant digits, and 22.3 has three significant digits.
With zeroes, the situation is more complicated:
1. Zeroes placed before other digits are not significant; 0.046 has two significant digits.
The solution provides detailed explanations and answers for the problem.
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
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.)
Question 3: Indicate the number of significant figures in each of the following measure quanties.
B: 205 m2 ___________________________
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
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?
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
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?
Lead (cm) Pb sphere
Silver (cm) Pb sphere
Aluminum (cm) Pb sphere
Question 10. Automobile batteries contain sulfuric acid, which is commonly referred to as "batter acid". Calculate the number of grams of sulfuric acid in 0.500 L of battery acid if the solution has a density of 1.28 g / mL and is 38.1% sulfuric acid by mass.
________________________________________________ g H2SO4 ( . 5L)