Substance Formula
Mass,
(g)
Physical Color
State
Density Boiling
, (g/cm) Point,
Methane
сн.
16.0
Gas
Colorless
0.423
-161.5
Ammonia
NH,
17.0
Gas
Colorless
0.70
-33
Unknown
???
???
???
???
???
???
Propane
CH
44.1
Gas
Colorless
0.493
-12.1
Bromine
Br.
159.8
Liquid
Red
4.04
58.8
Lithium
Li
6.94
Solid
0.534
1342
Silvery,
white
metal
Magnesium Mg
24.3
Solid
1.74
1090
Silver,
white
metal

Nebulae are enormous clouds in outer space. they are made mostly of hydrogen gas, helium gas, and dust. some nebulae glow brightly, while others do not. the stars that people see are huge, bright balls of glowing gas. they are made mostly of hydrogen and helium. which statement correctly describes other ways in which nebulae and stars are different? a. stars can form inside a nebula but a nebula can never be produced by any star. b. a star always has a higher density than a nebula. c. stars can never form inside a nebula but a nebula can be produced by any star. d. a nebula always has a higher density than a star.

Astable electron arrangement for an atom is one that does not easily change. how is this arrangement arrived at? a. valence electrons are transferred or shared to create a full outer shell of electrons. b. valence electrons are discarded into space to create a full outer shell of electrons. c. protons (positive charge) pair with valence electrons (negative charge) to create a strong bond. d. outer shells with valence electrons are transferred or shared.

The lattice enthalpy (formation of ionic solid from ions in the gas phase) for agcl(s) is -916 kj/mol and the hydration enthalpy (dissolution of gaseous ions into water) is -850 kj/mol. how much heat (in joules) is involved in forming 1l of saturated agcl solution (1.8 × 10-4 g / 100 ml water) by dissolving agcl(s)? assume solution volume does not change much upon dissolution. the equations are given below. ag+(g) + cl−(g) æ agcl(s)