The ancient remains or trace of once-living things.

During this reaction, P4 + 5O2 → P4O10, 1.5 moles of product were made in seconds. What is the rate of reaction? 0.011 g/min 210 g/min 380 g/min 850 g/min

At 63.5 C the vapor pressure of H2O is 175 torr and that of ethanol is 400 torr. A solution is made by adding equal masses of H2O and C2H5OH.

Consider an element Z that has two naturally occurring isotopes with the following percent abundances: the isotope with a mass number of 19.0 is 55.0% abundance and the isotope with a mass number of 21.0 is 45.0 % abundant.

Consider again the thermite reaction. If 0.0257 g Al react completely, what mass of Fe forms? Use the periodic table to find molar masses. Fe2O3 + 2Al → Al2O3 + 2Fe Select the correct setup for this calculation.

Which of the following is a step in the conversion of 2.5 hm3 to L? fraction cubed: one cm over ten to the second power m fraction cubed: one hm over ten to the negative 2 power m ten to the negative third power L over 1 mL fraction cubed: one ml

Facts about heat absorption and simple questions about heat absorption with answer

You measure a piece of wood with a meter stick and is it exactly one meter long. How many centimeters long is it?

When salt dissolved in water, what type of change occurs? A) physical only B) chemical only C) physical and chemical

Select all of the characteristics that define matter. A.) Matter has mass. B.) Matter has volume (takes up space). C.) Atoms and compounds are made out of matter. D.) All matter has the same density.

The science of observing and forecasting weather conditions is called