Given the following unbalanced thermochemical equation, how much heat will be released from the combustion of 45.5 grams of ch4 in an excess of oxygen gas? ch4(g) + 2o2(g) → co2(g) + 2h2o(l) + 890 kj

Aglow stick contains a glass vial with chemicals. when the glow stick is bent, the vial breaks and the chemicals react to produce a glow. a science student observes that a glow stick kept in the freezer glows for a longer duration than a glow stick kept at room temperature. what conclusion can be drawn based on the observation? be sure to note the outcome and test variables in the conclusion.

Which statement about hf is true? it is zero for any compound in its standard state. it is positive when the bonds of the product store more energy than those of the reactants. it is negative when a compound forms from elements in their standard states. it is zero for any element that is in the liquid state.

Nuclear decay is the spontaneous decay of one element into a. an x-ray b. a ray of light c. another element