Explain why sharpening a pencil is different type of physical change than freezing water to make ice cubes

What effect would thick cloud cover have on the temperature of the Earth's surface?

The men's world record for running a mile outdoors (as of 1999) is 3 min 43.13 s. At this rate, how long would it take to run a 2 km race (1 mi = 1609 m) ?

Give the coordination number for each metal ion in the following compounds: (a) [Co (CO3) 3]3 - (note that CO32 - is bidentate in this complex) (b) [Cu (NH3) 4]2+ (c) [Co (NH3) 4Br2]2 (SO4) 3 (d) [Pt (NH3) 4][PtCl4] (e) [Cr (en) 3] (NO3) 3 (f) [Pd

Which measurement is expressed with four significant figures? A. 3.876 * 103 kg B. 5.06 * 10-2 g C. 23.050 m D. 0.034 km

If 2.4 g of n2 gas has a volume of 0.40 l and a pressure of 6.6 atm, what is its kelvin temperature?

Describe in words the reaction represented by the equation and include a description of the composition of each kind of molecule 2h2+02=2h20

Potassium chloride, kcl, sodium sulfate, na2so4, glucose, c6h12o6, carbon dioxide, co2 and ammonium phosphate, (nh4) 3po4, are soluble in water.

Use the periodic table to select the element from the drop-down menu that has the correct relative electronegativity.

List the symbols for all the elements with electron configurations that end as follows. Each n represents an energy level.

Why is it necessary for the measuring devices to be clean