Answer:
CaO
Explanation:
CaO is the only compound that is a non-metal and a non-metal. The rest of the compounds are ionic, or metal and non-metal.
Answer:
Adding salt to the water increases the density of the solution because the salt increases the mass without changing the volume very much. When you add table salt (sodium chloride, NaCl) to water, the salt dissolves into ions, Na+ and Cl-. The volume increases by a small factor, but the mass increases by a bigger factor.
Explanation:
As the gas is heated, the particles will begin to move faster. Likewise if you start to cool a gas, the particles will move slower. Because the gas remains at a constant pressure and volume, the particles cannot spread out so they simply move around the container even faster.
Hope this helps :)
Answer:
Explanation:
The usefulness of a buffer is its ability to resist changes in pH when small quantities of base or acid are added to it. This ability is the consequence of having both the conjugate base and the weak acid present in solution which will consume the added base or acid.
This capacity is lost if the ratio of the concentration of conjugate base to the concentration of weak acid differ by an order of magnitude. Since buffers having ratios differing by more will have their pH driven by either the weak acid or its conjugate base .
From the Henderson-Hasselbach equation we have that
pH = pKa + log [A⁻]/[HA]
thus
0.1 ≤ [A⁻]/[HA] ≤ 10
Therefore the log of this range is -1 to 1, and the pH will have a useful range of within +/- 1 the pKa of the buffer.
Now we are equipped to answer our question:
pH range = 3.9 +/- 1 = 2.9 through 4.9
