3) The atomic number of magnesium is 12. This means that its nucleus must contain

A) 6 protons and 6 neutrons.

B) 6 neutrons and 6 electrons.

/C) 12 neutrons and no protons.

D) 12 protons and no electrons.

27b. You're in an airplane that flies horizontally with speed 1000 km/h (280 m/s) when an engine falls off. Ignore air resistance and assume it takes 30 s for the engine to hit the ground.

Communicating results allows scientists to learn from each other's results. True False

Technician A states that an average reading of 250mv from the O2 sensor is indicative of a lean exhaust. Technician B states that the technician should be checking for a leaking injector. Who is correct

The atomic number of an element is found by counting the

A wave has a frequency of 34 Hz and a wavelength of 2.0 m. What is the speed of the wave? Use. A. 17 m/s B. 36 m/s C. 0.059 m/s D. 68 m/s

A 0.0663 kg ingot of metal is heated to 241◦C and then is dropped into a beaker containing 0.395 kg of water initially at 25◦C. If the final equilibrium state of the mixed system is 27.4 ◦C, find the specific heat of the metal.

What does it mean when we say an atom has decayed?

If the mass of a material is 77 grams and the volume of the material is 19 cm3, what would the density of the material be

A bicyclist is in a 50-km race. She says she had an average velocity of 35. What is missing in the cyclist's velocity? A. units only B. units and distance C. direction only D. units and direction

Which one of the following statements concerning emf is true? A) Emf is the work done in moving the current from one terminal to the other of an emf device.