Which of the following is true about extinction? A. Only one extinction has occurred during the Earth's history. B. Plant species can become extinct, but animal species cannot. C. Extinctions have occurred many times throughout the Earth's history. D. Animal species can become extinct, but plant species cannot.

How many moles are in 250 grams of tungsten (w)? * 4.4x10^23 moles 4.2x10^23 moles 0.7 moles 1.4 moles

Describe what happens to the molecules as water goes from ice to liquid to vapor. be sure to explain what happens to the temperature during the phase changes.

The lattice enthalpy (formation of ionic solid from ions in the gas phase) for agcl(s) is -916 kj/mol and the hydration enthalpy (dissolution of gaseous ions into water) is -850 kj/mol. how much heat (in joules) is involved in forming 1l of saturated agcl solution (1.8 × 10-4 g / 100 ml water) by dissolving agcl(s)? assume solution volume does not change much upon dissolution. the equations are given below. ag+(g) + cl−(g) æ agcl(s)