Blog

According to this graph, when did humans begin to have an effect on global temperatures? (You may find it helpful to use a piece of scratch paper as a straight edge to line up the temperature graph with the time scale.)

An element from column 1A on the periodic table will combine with an element from column 7A on the periodic table in a one-to-one ratio.   How many more electrons does an element in column 7A need to fill its shell?

At hot spots and diverging plate boundaries, less dense mantle rock, without any introduced water, is pushed up toward the surface. The rock stays at the same temperature. As mantle rock that is near its melting point rises toward the surface, which of the following happens?

Use this information to answer the next two questions: This graph indicates the melting range for mantle rock at different pressures (left) and the melting range for mantle rock in the presence of H2O (right). Image Description Image of two graphs. The graph on the left shows pressure (y-axis) versus temperature (x-axis). At the bottom right where temperature and pressure are low, the rock is all solid. The top right of the graph shows the rock as all liquid where temperature is high and pressure is low. Starting with low temperature and pressure, as you move toward greater temperature and pressure, a zone of melting runs from the top and bottom along the center of the graph. It starts where pressure is high and temperature is low and curves to the bottom right of the graph as temperature and pressure both increase. The graph on the right shows pressure versus temperature with water. At the bottom right where temperature and pressure are low, the rock is all solid. The top right of the graph shows the rock as all liquid where temperature is high and pressure is low. Starting with low temperature and pressure, as you move toward greater temperature and pressure, a zone of meltling with water cuts across the first half of the graph. It starts where pressure is high and temperature is low and stays in the melting zone as pressure increases and temperature stays low. As temperature gets higher alongside pressure, the meling zone with water curves to the bottom of the graph ending where you have medium temperature and high pressure.

Uranium-238 alpha decays, emitting a helium-4 nucleus. What is the mass number of the product?

Which of these fatty acids has a low melting point? (Which one would be likely to be a liquid at room temperature?)

An astronomer discovers brightly glowing disk of gas in space surrounding a neutron star, like the one pictured below. What would they say happened?    Attributions Images NASA, ESA, and Z. Levay (STScI); Radio: NRAO/AUI/NSF GBT+VLA 1.4 GHz mosaic (Dyer, Maddalena and Cornwell, NRAO); X-ray: NASA/CXC/Rutgers/G. Cassam-Chenai and J. Hughes et al.; Optical: F.Winkler/Middlebury College and NOAO/AURA/NSF; and DSS. Full-shell Image of SN 1006 Showing Location of Hubble Observations [photograph]. (public domain). Via NASA.

The wave model replaced the Bohr, modified solar system model of the atom because the wave model can explain and predict things when the Bohr model either fails to explain them or provides incorrect predictions. Which of the following is one of the reasons that the wave model is better than the Bohr model?

These experiments with electrons and slits told us something important about the nature of electrons. They tested and confirmed a new idea about electrons. What new information did we learn from these results?

What can you conclude from the cross-section below?