Week 1 Key Practice Problems

Week 1 Key Practice Problems - CHEMISTRY 201X Practice...

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
CHEMISTRY 201X August 20-24, 2007 Practice Problems (KEY) (1) Label each of the following as either a chemical or a physical process: (a) Dissolving sodium chloride in warm water; Physical process (b) Adding sodium metal to water resulting in a basic solution; Chemical process (c) Heating a helium-filled balloon until it pops; Physical process (d) Igniting a hydrogen-filled balloon until it explodes. Chemical process (2) Write down specific definitions for the following terms: (a) Flammable; Easily ignited and capable of burning; substances may be solids, liquids or gases; A flammable liquid as "any liquid having a flash point below 100 ° F (37.8 ° C.), except any mixture having components with flash points of 100 ° F (37.8 ° C) or higher, the total of which make up 99% or more of the total volume of the mixture. Source : http://www.ilpi.com/msds/ref/flammable.html (b) Corrosive; Capable of destroying or eating away by chemical action; Causes visible destruction of, or irreversible alterations in, living tissue by chemical action at the site of contact. (c) Pyrophoric; Can spontaneously ignite in air. (d) Teratogenic. Causing malformations of an embryo or fetus. (3) Discuss reasons why a liquid is considered to be both condensed matter and a fluid . Since the atoms or molecules of a liquid are confined to a specific volume, the liquid is considered to be condensed matter ; however, these same atoms or molecules have substantial kinetic energy in this state, and so can flow (one way it shows this is by adopting the shape of the container). (4) Gold can be hammered into extremely thin sheets called gold leaf . (a) What is the property described by this sentence? Malleability (b) If a 206.0 mg piece of gold is hammered into a sheet measuring 75.0 cm long and 30.0 cm wide, what is the average thickness (in cm) of the gold sheet? (HINT: you will need the density of gold to answer this question.) t = 4.74 × 10 6 cm; 3 g 0.206 g 19.32 = cm 75.0 cm×30.0 cm×t (c) If a gold atom is considered to be spherical with a diameter of 360.0 pm, approximately how many planes of gold atoms are stacked on each other to form this gold leaf?
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
CHEMISTRY 201X August 20-24, 2007 Practice Problems (KEY) # planes = 1.32 × 10 4 ; -6 -10 thickness 4.74×10 cm #planes = atom diameter 360.0×10 cm
Background image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 6

Week 1 Key Practice Problems - CHEMISTRY 201X Practice...

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online