Why leather gets hardered after tanning

Radioactivity was discovered around: 1600 1700 1800 1900

1. Consider the reaction: N2 (g) + O2 (g)  2NO (g) + Cl2 (g) A reaction mixture at 400  C has the following composition: [NO] = 0.01 M, [N2] = 0.001 M, and [O2] = 0.001 M. (Kc = 0.0156 at 400  C).

If Bromine has a density of 7.52 g/ml, which of the following will float in Bromine? Gold 19.32 g/ml Calcium 2.4 g/ml Aluminum 4.2 g/ml Silver 10.50 g/ml

The precision of a balance is + 0.02 g. The accepted value for a measurement is 26.86 g. Which measurement is in the accepted range? • 26.029 26.82 g 26.87 g 26.90 g

Assume that one grain of sand has an average size of 1 millimeter across. Based on the chemical composition of sand, can you guess how many atoms are in just one grain of sand? Twenty million? Twenty billion? Keep going.

What is the [H3O+] of a solution with a pH of 2.56? 2.56 M, 2.75 x 10-3 M, 363 M, or - 0.408 M

What is the law of conservation of energy? A) energy can only be destroyed B) energy will always be renewed. C) energy cannot be created of destroyed. D) energy can never change forms.

Most metals are solid at room temperature, malleable, ductile, good conductors of heat and electricity, and react in acids to produce hydrogen gas. which of the properties mentioned is a chemical property? a. are malleable b. reacts with acids c.

Silver tarnishes when it comes into contact with hydrogen sulfide in the air. physical property or chemical property

When a volcanic irruption adds new rock to existing land and forms new islands is it considered destructive?