Question

What is the volume of 3.0 g of lead? The density of lead is 11.34 grid. A) 0.26 mL B) 3.78 mL C) 3.8 mL D) 34 mL E) 34.2 mL 5. If airplane's speed is 850 mi/hr, what is its speed in m/s (meters/second)? A) 40 m/s B) 1360 m/s C) 380 m/s D) 528 m/s E) 4.0 times 105 m/s 6. The decomposition of water into H2 and O2 is A) a physicla change because the water merely disappers B) an example of the formation of ionic compounds. C) a chemical change because one comp0und is converted into new compounds, D) a nuclear reaction. E) just a physical change since water is liquid, and H2 and O2 are gases.

Answer 1

4) we knwo that

Density = Mass / Volume

So volume = Mass / Density = 3 / 11.34 = 0.264 mL = 0.26 m L

5) we know that

1miles / hour = 0.447 m /s

So 850 miles / hr = 0.447 X 850 m /s = 379.95 m /s = 380 m/s

6) It is a chemical change as one compound is converted to two compounds

Water is not ionic

It is not a nuclear reaction

Not a physical change