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Perform the following conversions between energy units. a) 721 kJ  =  [i_1] ×10[i_2] J b) 3255 kcal  =  [ii_1] × 10[ii_2] kJ c) 5.50 ×106 J  =  [iii_1] × 10[iii_2] kcal

How many double bonds are present in the Lewis structure of NO2- in which the formal charge of N is zero?

Calculate the enthalpy change for the following reaction: 2CO(g) + 4H2O(l) → 2CH4(g) + 3O2(g) ∆H = ? Given the following reactions and their ∆H values: CH4(g) + 2O2(g) → CO2(g) + 2H2O(l) ∆H = -890.0 kJ 2CO(g) + O2(g) → 2CO2(g) ∆H = -566.0 kJ

Calculate the pressure of 2520 moles of hydrogen gas stored at 27.0oC in the 180. L storage tank of modern hydrogen-powered car.

What are the bond angles around a central atom with sp hybridized orbitals?

Calculate the molar mass of a gas if 0.728 g of this gas occupies 0.250 L at 0.955 atm and 297 K. Show all your work for full credit. Use the correct number of significant figures.

Determine whether the following reaction is a redox reaction. If it is, identify the element that is oxidized, the element that is reduced, the oxidizing agent, and the reducing agent. Mg(s) + 2HCl(aq) → MgCl2 (aq) + H2(g)

Determine whether the following reaction is a redox reaction. If it is, identify the element that is oxidized, the element that is reduced, the oxidizing agent, and the reducing agent. C8H18(g) + 25O2(g) → 16CO2(g) + 18H2O(l)

Given the following Lewis structures for cyanate ion: 1. What is the formal charge of each atom in structure A? a) Formal charge of O [a] b) Formal charge of C [b] c) Formal charge of N [c] 2. What is the formal charge of each atom in structure B? a) Formal charge of O [d] b) Formal charge of C [e] c) Formal charge of N [f] 3. What is the formal charge of each atom in structure C? a) Formal charge of O [g] b) Formal charge of C [h] c) Formal charge of N [i] 4. Based on the formal charges determine which Lewis structure (A. B, or C) is more favorable? [j]

Determine whether the following reaction is a redox reaction. If it is, identify the element that is oxidized, the element that is reduced, the oxidizing agent, and the reducing agent. 3Ca(s) + 2N2(g) → Ca3N2(s)