Which process involves a decrease in entropy? burning natural gas water freezing into ice water evaporating on heating dry ice subliming

Which statement correctly describes a physical change? a. involves breaking and creating chemical bonds but not changing a phase b. may involve a change in phase but does not involve a change in the molecular structure c.

Hydrogen is a liquid below what temperature? a. 100 degrees C c. -183 degrees C b. -253 degrees C d. 0 degrees C

A container with 0.317 L of water is placed into microwave and is then radiated with electromagnetic energy that has a wavelength of 13.3 cm. The temperature of the water then rose by 74.3 °C.

Which of the following aqueous solutions are good buffer systems? 0.25 M ammonium nitrate + 0.40 M ammonia 0.23 M nitric acid + 0.20 M sodium nitrate 0.16 M potassium hydroxide + 0.22 M potassium chloride 0.39 M hypochlorous acid + 0.

Which polymer is a biopolymer? polystyrene polyethylene polylactic acid polyvinylchloride

7. The molar mass of carbon is 12.0 g/mol, of hydrogen is 1.0 g/mol, and of oxygen is 16.0 g/mol. How would you calculate the molar mass of ethanol (C2H60) ? • 9 mol * 6.02 x 10^23g • 2 x 12.0g/mol + 1 x 16.0 g/mol • 9 mol (12.0 g/mol + 1.

Science is 2 things. Describe what those 2 things are

What does the subscript in a chemical formula represent (the 2 in H2) ?

How many significant figures are in the measurement, 0.005890 g? 4 6 7 5 8

When pure methanol is mixed with water the resulting solution feels warm would you expect this solution to be ideal? Explain