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What is the molality of a 10.0% (by mass) aqueous solution of potassium nitrate (KNO3)?   Hint:  The molar mass of potassium nitrate is 101.1 g/mol.

The n = 2  →  n = 4 transition in the Bohr hydrogen atom corresponds to the ________ of a photon with a wavelength of _________ nm?

What is the new boiling point (in °C) of a 1.75m aqueous solution of Na2SO4? Hint: The molal boiling point elevation constant (Kb) of water is 0.512°C/m.

Which of the following ionic compounds has the greatest lattice energy?

What is the correct chemical formula of a compound composed of potassium ions and phophate ions?

In which of the following species does the central atom VIOLATE the octet rule?

Quick breads and biscuits use the thermal decomposition of sodium bicarbonate as their source of gas for rapid inflation instead of yeast to make the dough rise. The chemical reaction follows:                                              2 NaHCO3 (s) → Na2CO3 (s) + CO2(g) + H2O (g) What mass (g) of NaHCO3 is required to produce 3.60 L of CO2 gas at 420 K and 1.00 atm? Hint:  molar mass of NaHCO3 is 84.01 g/mol 

What is the new freezing point (in °C) of a 1.50m aqueous solution of CaCl2 ? Hint: The molal freezing point depression constant (Kf) of water is 1.86°C/m.

125 g of Cu(NO3)2 is added to enough water to produce 485 mL of solution. What is the molarity (in M) of this solution? Hint: molar mass copper (II) nitrate = 187.57 g/mol

For the diethyl azodicarboxylate molecule (DEAD) below, the hybridization for arrow indicated oxygen atom is _______ and there is/are  _______  pi (π) bond(s) in the structure. Hint:  Not all H and C are written out.  Consider the bonded hydrogens and the lone pairs that are not depicted on the structure but may needed to complete an octet.