Evidence suggests that giraffes once had short necks. how does natural selection explain why giraffes now have long necks

Classify each amino acid according to whether its side chain is predominantly protonated or deprotonated at a pHpH of 7.40.7.40. The pKapKa values of the Asp, His, and Lys side chains are 3.65, 6.00, and 10.53,3.65, 6.00, and 10.53, respectively.

The direction and speed of an object is described by its

Alkenes can be converted to alcohols by hydroboration-oxidation. Draw a structure showing one of the alcohols formed in the following reaction sequence. Use wedge-and-dash bonds to indicate stereochemistry.

Given the following chemical reaction: 2 O2 + CH4 CO2 + 2 H2O What mass of CH4 is required to completely react with 100 grams of O2? 6 C 12.01 Carbon 1 H 1.01 Hydrogen 8 O 16.00 Oxygen A. 10 grams CH4 B. 20 grams CH4 C. 25 grams CH4 D. 45 grams CH4

How many grams of nitric acid will react completely with a block of iron metal that is 4.5 cm by 3.0 cm by 3.5 cm, if the density of iron is 7.87 g/mL? Show all steps of your calculation as well as the final answer. Fe + HNO3 → Fe (NO3) 3 + H2

Mendeleev's arrangement of elements in the periodic table was based on the observations and experiments of his predecessors who studied mass and properties of elements. True or false?

How many moles do you need to prepare 1.675 L of a 8.50 M NaOH solution? Round your answer to 2 decimal places.

For the following SN1 solvolysis reaction, select the correct rate equation and the overall reaction order (note: CH3OH is the solvent for the reaction). (CH3) 3CCl + CH3OH → (CH3) 3OCH3 + HCl

Which of the following is not a possible sublevel? 1s 2p 3f 4d

Fish breathe oxygen, o2, dissolved in the water. since water is a polar substance and oxygen is a nonpolar substance, how can there be any oxygen, o2, in the water?