13 A 4.85 g sample of anhydrous sodium sulfate is dissolved in water and the solution made up to
250 cm in a volumetric flask.
What is the concentration in mol dm- of sodium sulfate in the solution?
A
0.0341
B
0.137
NO
С
0.163
D
0.273
O
А

Which statement describes covalent bases? they have hydroxide ions. they produce hydrogen ions. they are often amines. they are named the same as ionic compounds.

What does x represent in the formula for the compound xcl4?

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.