According to the following thermochemical equation, what mass of HF (in g) must react in order to produce 345 kJ of energy? Assume excess SiO2. SiO2(s) + 4 HF(g) → SiF4(g) + 2 H2O(l) ΔH°rxn = -184 kJ

Brad and his family like to go camping. they always take a gas lantern with them. the lantern can take fiuels but always puts out the same amount of light. brad has two different kinds of fuel for the lantern. how can he figure out which kind of fuel has more chemical energy that the lantern can turn into light? measure the brightness of the lantern using each kind of fuel by comparing it to the full moon. g measure the volume of the containers of fuel. measure how long the lantern stays lit on a fixed amount of fuel. measure the mass of each container of fuel using a balance scale. answer 12

Read the given expression. x = number of protons − number of core electrons which of the following explains the identity of x and its trends across a period? x is the effective nuclear charge, and it remains constant across a period. x is the screening constant, and it remains constant across a period. x is the effective nuclear charge, and it increases across a period. x is the screening constant, and it increases across a period.

What are transitions between a liquid and gas called? identify which way they are transitioning