Determine the molarity of a solution when 17.21 g of the hypothetical molecule Q2X6 is dissolved in enough water to create 225.0 mL of solutions. (Use the information about the elements provided below.)

Which of the following statement(s) is/are correct  Sample A can be a representation of a flask containing carbon monoxide gas.  Sample B can be a representation of a flask containing nitrogen dioxide gas. Sample C can be a representation of a flask containing helium gas and hydrogen gas. 

Given the following equations:  Reaction  △H  2 A(s) + 3 B (g) ⟶ 2 C (s)  -800.0 kJ  D(s) + 2 B (g) ⟶ E (s)   -640.1 kJ  Determine the enthalpy change (in kJ) for the reaction below and whether the reaction is exothermic or endothermic.  3 E (s) + 4 A (s) ⟶ 4 C (s) + 3 D (s)   

Which of the following is the electronic configuration for the Ni2+ ion?

Determine the amount of heat released (in kilojoules) when 18.20 grams of ethane, C2H6, undergoes combustion according to the following equation: 2C2H6 (g) + 7O2 (g) 

How many moles K3PO4 would be produced if 18 moles of KOH were used in the reaction? The unbalanced chemical equation is given below.                        3KOH  +  H3PO4 ⟶  K3PO4  +  3H2O

Using the conversion units provided to determine how many cds are in 4.56 bks?   12.5 cds = 1.89 rcd  2.16 vms = 4.35 bks  9.98 vms = 3.22 rcd     

Which of the following statement(s) about phase transitions is/are correct? Vaporization refers to the phase transition from liquid to gas. Freezing refers to the phase transition from solid to liquid Sublimation refers to the phase transition from solid to gas.

Which of the following is the electronic configuration for the Fe2+ ion?

A flask contains 35.4 mL of a 3.76 M aqueous solution of KMnO4. A student adds 300.0 mL of water to the flask. What is the concentration of KMnO4 in the flask after the addition of the water?