What is the valence of selenium

Which example shows electrical energy being transformed into heat energy?

When 0.1523 g of liquid pentane (CH) combusts in a bomb calorimeter, the temperature rises from 23.7C to 29.8 C. What is U for the reaction in kJ/mol pentane? The heat capacity of the bomb calorimeter is 5.23 kJ/C.

A taxi hurries for 1 3/4 hours with a constant speed of 84 mph and then for another 1 hour 45 minutes with a constant speed of 24 mph. what is its average speed for the total trip?

I need information on sound energy.

True or false: Satellites, rovers and astronomical accomplishments (now commonly related to aerospace engineering) can all be categorized originally as mechanical engineering endeavors.

a boy hears the echo of his own voice from a distance hill after 0.8 seconds. If the speed of sound in air is 340m/s, calculate the distance of the hill from the boy.

Which of the following are found in plant cells buh not animal cells?

The diagram shows the field lines near the poles, X and Y, of two magnets Based on the field lines, what are the poles of the magnets? O X: north Y south X: south Y north X north Y north Х Y X south Y south

Why is it safe to watch an eclipse of the Moon but not an eclipse of the Sun

A student holds two pieces of paper at the top, 10 cm apart. The flat sides of the papers face each other. What happens when the student uses a straw to blow a stream of air between the papers?