Which two compounds have the same empirical formula? A. NO2 and N2O4 B. H O and H2O C. CH2 and C3H8 D. C2H2 and C2H4

A shiny block weighs 34.567 g and measures 3.5 cm in length, 2.0 cm in width, and 1.5 cm in thickness. What is it's volume and density? With work to show

If you have 120. mL of a 0.100 M TES buffer at pH 7.55 and you add 3.00 mL of 1.00 M HCl, what will be the new pH? (The pKa of TES is 7.55.)

An atom has atomic number 11 and mass number 23. How many electrons does the atom have?

Does an oxygen atom form two covalent bonds?

What is the mass number of an atom having 16 protons and 13 neutrons?

In the fourth century bc Greek scholars rejected Democritus ideas about the atom. This rejection was mostly based on?

An element X has two isotopes. X-15 has 7 protons and 8 neutrons. Determine the atomic number and mass number of the second isotope, which has 10 neutrons in its nucleus. a. atomic number = 8; mass number = 9 b. atomic number = 8; mass number = 17 c.

Which statement best describes the direction of heat flow by conduction between two samples of the same material? 1. Heat flows from faster molecules to slower molecules when they are near. 2.

Delta H equals 98.8 KJ, and Delta S equals 141.5 J/K. Is this reaction spontaneous or nonspontaneous at high and low pressure

Secondary consumers are eaten by?