For the hypothetical reaction A → B, calculate the average rate of disappearance of A if the initial concentration of A is 0.91 M and the concentration of A after 90 minutes is 0.11 M.

Why is scientific notation used?

Which change would increase the mechanical advantage of dentures, which are artificial teeth?

You are asked to explain the Earth's magnetic field. Which is the best reply? A.) The Earth's magnetic south is similar to the north pole of a magnet. B.) The Earth's core has a strong magnetic charge similar to the south pole of a magnet. C.

A bobsled team accelerates their 150 kg sled at a rate of 3 m/s^2. How much force did they use?

A building 190 feet tall casts a 30 foot long shadow. if a person stands at the end of the shadow and looks up to the top of the building, what is the angle of the person's eyes to the top of the building (to the nearest hundredth of a degree) ?

Which of the following is an example of heat transfer through radiation? A. A pot of soup warming on a hot burner. B. A crayon melting on a hot sidewalk. C. Beach sand getting warmed by the sun. D. An egg getting cooked in a pot of boiling water.

Which of the following best describes each particle? A. Protons are negative, neutrons are neutral, and electrons are positive. B. Protons are neutral, neutrons are positive, and electrons are negative. C.

During World War II, both the Allied and Axis powers used propaganda to A. weaken public support for the war. B. downplay public opinion. C. manipulate the public through the use of humor. D. shape public support of the war

What type of simple machine is a hand drill? A) pulley B) wedge C) ramp D) screw

Calculate the wavelength and frequency of the radiation emitted by the electronic transition from the 10th to the 9th excited state of hydrogen.