Consider the reaction: 2 HCl (aq) + Ba(OH)2 (aq) → BaCl2 (aq) + 2 H2O (l) ∆H = –118 kJ Calculate the heat when 200.0 mL of 0.500 M HCl is mixed with 300.0 mL of 0.200 M Ba(OH)2. Assuming that the reaction goes to completion, the temperature of both solutions was initially 25.0 oC, the final mixture has a mass of 500.0 g and a specific heat capacity of 4.18 J g –1 oC –1, calculate the final temperature of the mixture. Assume no heat is lost to the calorimeter and surroundings.

The table compares the number of electrons in two unknown neutral atoms. comparison of electrons atom number of electrons a 10 d 11 use this information to determine the number of valence electrons in the atoms. which of the following correctly compares the stability of the two atoms? both are unreactive. both are highly reactive. a is unreactive and d is reactive. a is reactive and d is unreactive.

Great amounts of electromagnetic energy from our sun and other bodies in space travel through space. which is a logical conclusion about these electromagnetic waves? their energy must be very their frequency must be very low these waves can travel without a medium they only travel through a vacuum of space

Lab reagent, hypothesis test. a reference solution used as a lab reagent is purported to have a concentration of 5 mg/dl. six samples are taken from this solution and the following concentrations are recorded: (5.32, 4.88, 5.10, 4.73, 5.15, 4.75) mg/dl. these six measurements are assumed to be an srs of all possible measurements from solution. they are also assumed to have a standard deviation of 0.2, a normal distributin, and a mean concentration equal to the true concentration of the solution. carry out a significance test to determine whether these six measurements provide reliable evidence that the true concentration of the solution is actually not 5 mg/dl.