Describe the particles that make up a pure substance

How many molecules are contained in 127 grams of iodine?

How many unpaired electrons are there in helium?

Part a a solution is made by mixing 9.00 mmol (millimoles) of ha and 3.00 mmol of the strong base. what is the resulting ph? express the ph numerically to two decimal places.

Methane and oxygen react to form carbon dioxide and water. what mass of water is formed if 6.4 g of methane reacts with 25.6 g of oxygen to produce 17.6 g of carbon dioxide?

If 1.87 g‎ of acetic acid (ch3co2h) ‎ reacts with 2.31 g‎ of isopentylalcohol (c5h12o) ‎ to give‎ 3.20 g of isopentylacetate (c7h14o2) ‎, what is the percent yield of the reaction?

Arrange the elements in order of increasing atomic radius Mg Ba F S

Based on the enthalpy changes given for the reactions, which reactions are endothermic? (check all that apply) 2H2O → 2H2 + O2, ΔH = 484 kJ C + O2 → CO2, ΔH = - 394 kJ H2 + Br2 → 2HBr, ΔH = - 73 kJ 2NH3 → N2 + 3H2, ΔH = 92 kJ

Which of the following is not true about performing biological investigations reading and understanding Metric system

At 29°C, Kp = 5.3 ✕ 102 atm-2 for the following reaction. N2 (g) + 3 H2 (g) equilibrium reaction arrow 2 NH3 (g) When a certain partial pressure of NH3 (g) is put into an otherwise empty rigid vessel at 29°C, equilibrium is reached when 55.

If ice is heated at constant pressure of 0.0512 ATM will it