A reaction occurs in a calorimeter, resulting in the starting and final temperatures shown below. What can you say about the reaction and the enthalpy change (ΔH) during the reaction? Starting: 21.0 C Final: 38.8 C

When pure sodium hydroxide is dissolved in water, heat is evolved. In a laboratory experiment to measure the molar heat of solution of sodium hydroxide, the following procedure was followed. To a calorimeter containing 3.00 * 10^2 g of water at 20.

How is electron movement related to covalent bonding in ammonia, NH3? A) Electrostatic sharing in a sea of electrons around the atoms allows bonds to form. B) The atomic orbitals overlap and electrons are shared between the atoms forming bonds.

Which of these is a reason gold is more expensive than metals like aluminum? A) Gold is rarely found in Earth's crust. B) Gold is the most common metal on Earth. C) Gold is one of the lightest metals known to man.

Explain why c 12 6 and c 14 6 are istopes of carbon

After three half-lives, a sample contains 20 grams of parent isotopes. How many grams of the parent isotope were present to start?

Why is it possible to safely drink a solution that contains a 50:50 mixture of equal concentrations of a strong acid and a strong base, either of which, if ingested separately, would be very caustic and damaging?

Explain why many compounds that contain one or more hydrogen atoms are not classified as arrhenius acids

pure substance x is a green powder. when heated, it gives off a gas and changes to a black powder. is substance x an element or a compound? give reasons

What amount (moles) is represented by each of these samples? a. 20.0 mg caffeine, c8h10n4o2 b. 2.72 1021 mo?

A sample of gas occupies 40.0 mL at - 123°C. What volume does the sample occupy at 27°C if the pressure is held constant? V1T2 = V2T1 Don't forget to convert temperature to kelvin! Group of answer choices 8.80 mL 20.0 mL 80. ML 182 mL