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Which bond represent polar covalent bonds?

Nitrogen has two stable isotopes:  14N with a mass of 14.004 amu and 15N with a mass of 15.000 amu.   Without doing calculations, you could conclude that the most abundant isotope is:

Which of the following are electrolytes? Solubility Rules  Li+, Na+, K+, Rb+, NH4+ All salts containing alkali metal ions and the ammonium ion are soluble     NO3-, C2H3O2- All nitrates and acetates are soluble     Cl-, Br-, I- Most chloride, bromide, and iodide salts are solubleExceptions are Ag+, Hg22+, and Pb2+ which are insoluble     SO42- Most sulfate salts are solubleExceptions are Ca2+, Sr2+, Ba2+, and Pb2+ which are insoluble     CO32-, PO43-, CrO42- Most carbonates, phosphates, and chromate salts are insolubleExceptions are the Group IA elements and NH4+ which are soluble     OH- Most hydroxide salts are insolubleExceptions are Group IA elements and NH4+ which are solubleCa2+, Sr2+, Ba2+ are slightly soluble (considered to be insoluble)     S2- Most sulfide salts are insolubleExceptions are Group IA elements NH4+ and Ca2+, Sr2+, and Ba2+ which are soluble

How much of a 500.0 mg sample of a radioactive isotope is left after 5 half lives? mf = mi 12n{“version”:”1.1″,”math”:”mf = mi 12n”}

In an alcohol solution 45.6 g of alcohol is dissolved in 254 g of water.  Calculate the mass percent of alcohol in the solution.

For the chemical reaction:  N2 (g) + 3 H2 (g) → 2 NH3 (g) How many mols of ammonia (NH3) are produced if 2.8 moles of hydrogen gas react with excess nitrogen?

A nurse is hanging an IV bag that contains a 3.0 % potassium phosphate solution.   This means that:

A 3.23-g sample of  gas exerts a pressure of 2.33 atm in a 500-mL flask at a temperature of 350. K.  Calculate the molar mass of the gas. Given PV = nRT R = 0.08206 atm · Lmol · K{“version”:”1.1″,”math”:”R = 0.08206 atm · Lmol · K”}

Select the correct formulas and corresponding names of acids.

How many dots should the Lewis symbol for F contain?