3. Which element is most important for growing crops?

a. carbon dioxide

BA

b. hydrogen

C. calcium

d. nitrogen

4. Who discovered how to manipulate equilibrium systems?

Lithium aluminum hydride reduces carboxylic acids to primary alcohols via what intermediate? A) a ketone. B) a methyl ester. C) an aldehyde. D) a secondary alcohol. E) an acid chloride.

Element that has two isotopes has an average atomic mass of 199.7. if 75.56% of the atoms of the element have an atomic mass of 197.4, what is the atomic mass of the other isotope?

Which of the following is an example of a chemical change? Gasoline evaporating. A ice cube melting. Toasting a marshmallow. Mixing sugar and water.

If you need to do a 1:20 dilution on a culture to get acceptable plate counts, how many milliliters of original sample will you add to a final volume of 0.1 mL? For this course, a 1:20 dilution is 1 part culture to a final volume of 20 parts.

Out of 2 elements, how do you know which one is more metallic?

Identify water. weak electrolyte, weak acid nonelectrolyte strong electrolyte, strong acid weak electrolyte, strong acid strong electrolyte, weak acid

What is the atomic weight of a hypothetical element consisting of two isotopes, one with a mass of 62.2 u which is 24% abundant, and the other with a mass of 64.0 u?

A pure compound contains 24 g C, 4 g H, and 32 g O. If no other elements are present, determine the empirical formula of the compound. Be sure to show your work.

One method for preparing pure iron from Fe2O3 is by reaction with carbon monoxide. Fe2O3 (s) + CO (g) →Fe (s) + CO2 (g) How many moles of carbon monoxide are needed to react completely with 122 kg of Fe2O3.

A microspectrophotometer measures which of the following? Electrons Electricity Light absorption Pigments