identify 2 changes of state that require energy to be used, and 2 changes of state that require the release of energy

Classify the possible combinations of signs for a reaction's ΔH and ΔS values by the resulting spontaneityA. ΔH is positive and ΔS is negativeB. ΔH is positive and ΔS is positiveC. ΔH is negative and ΔS is positiveD.

1) When elements combine to form compounds: A) their properties are an average of all elements in the compound. B) their properties change completely. C) their properties do not change. D) their properties are completely random. E) none of the above

What is common to all of the oxidation reactions in the krebs cycle?

Tin (Sn) exists in Earth's crust as SnO2. Calculate the percent composition by mass of Sn and O in SnO2.

Which of the following elements has the lowest electronegativity? a. lithium b. Carbon C. bromine d. fluorine

A cube has a depth of 10 cm. What is the volume of the cube? Or What is depth?

A sample of NO2 in a 1550 mL metal cylinder at 70.26 kPa has its temperature changed from 480oC to - 237oC while its volume is simultaneously changed by a piston to 5114 mL. What is the final pressure in kPa?

How many grams of methane gas (CH4) are in a 15.8-liter sample at 1.2 atmospheres and 27°C? Show all work used to solve this problem

Oxygen forms a number of compounds with sulfur, many of which are quite reactive. One such compound is 57.20 % by mass S. Calculate the number of grams of oxygen present in a sample of this compound that contains 50.00 grams of S.

What is meant by "pressure of the atmosphere?" What causes this pressure?