The chart below shows the dates of eclipses in the years 2006 and 2007. what is the best explanation for the frequency of eclipses? a. the moon's orbit is tilted relative to the plane of the earth's orbit. about every six months, the sun, moon and earth are aligned enough for a solar and a lunar eclipse to occur. b. the earth and moon orbit the sun in opposite directions. when the moon's orbit crosses the earth's orbit, a lunar or solar eclipse will occur. c. a lunar or a solar eclipse occurs every time the moon orbits the earth. the moon orbits the earth four times a year. d. the atmospheric conditions that cause eclipses are only found at certain locations and times of year.

The chemical effect of the endocrine system is longer lasting than the chemical effect of the nervous system. select the best answer from the choices provided t f

1. how much energy is needed to raise the temperature of 40.0 g of argon from 25c to 40c? the specific heat capacity of argon is 0.520 j/(g·k) 2a. 23.0 ml of 0.100 m hcl (standard) are added from a buret to neutralize 50.0 ml of an unknown basic solution. 2b. if the oh- produced in the previous reaction came from ca(oh)2, then what is the molarity of the ca(oh)2? 3.calculate the new freezing-point of a solution when 60.5 grams of cacl2 solute is dissolved in 0.612 kg of water. 4. what is the maximum number of moles of alcl3 that can be produced from 5.0 mol al and 6.0 mol cl2? 5. a sample of oxygen gas has a volume of 150 ml when its pressure is 0.923 atm. if the pressure is increased to 0.987 atm and the temperature remains constant, what will the new volume be? 6. nitrogen gas in a closed container at a temperature of 100.0 oc and 3.0 atm is heated to 300 oc. what is the pressure of the gas at the higher temperature?

Asmall object with mass 0.200 kg swings back and forth on the lower end of a light rope that is 3.00 m long. the upper end of the rope is attached to the ceiling. as the object swings through its lowest position, where the rope is vertical, the speed of the object is 5.80 m/s. at this point in the motion, what is the tension in the rope? (use g = 9.80 m/s2.)