Answer the following question given this paragraph: Minerals that are not pure elements are made of chemical compounds. For example, the mineral quartz is made of the compound silicon dioxide, or SiO 2 . This compound has one atom of the element silicon for every two atoms of the element oxygen. Q: Minerals that are not pure elements are made of what? Choices: - isotopes - noble gases - metalloids - chemical compounds A:
chemical compounds

Answer the following question given this paragraph: The Sun was the first object to form in the solar system. Gravity pulled matter together to the center of the disk. Density and pressure increased tremendously. Nuclear fusion reactions begin. In these reactions, the nuclei of atoms come together to form new, heavier chemical elements. Fusion reactions release huge amounts of nuclear energy. From these reactions a star was born, the Sun. Q: What was the first object to form in the solar system? Choices: - earth - moon - jupiter - sun A:
sun

Answer the following question given this paragraph: 24.4 Energy in Electromagnetic Waves Anyone who has used a microwave oven knows there is energy in electromagnetic waves. Sometimes this energy is obvious, such as in the warmth of the summer sun. Other times it is subtle, such as the unfelt energy of gamma rays, which can destroy living cells. Electromagnetic waves can bring energy into a system by virtue of their electric and magnetic fields. These fields can exert forces and move charges in the system and, thus, do work on them. If the frequency of the electromagnetic wave is the same as the natural frequencies of the system (such as microwaves at the resonant frequency of water molecules), the transfer of energy is much more efficient. Connections: Waves and Particles The behavior of electromagnetic radiation clearly exhibits wave characteristics. But we shall find in later modules that at high frequencies, electromagnetic radiation also exhibits particle characteristics. These particle characteristics will be used to explain more of the properties of the electromagnetic spectrum and to introduce the formal study of modern physics. Another startling discovery of modern physics is that particles, such as electrons and protons, exhibit wave characteristics. This simultaneous sharing of wave and particle properties for all submicroscopic entities is one of the great symmetries in nature. Q: If the frequency of the electromagnetic wave is the same as the natural frequencies of the system, the transfer of what is much more efficient? Choices: - heat - sound - light - energy A:
energy

Answer the following question given this paragraph: Suppose that you wanted to know how many hydrogen atoms were in a mole of water molecules. First, you would need to know the chemical formula for water, which is H 2 O. There are two atoms of hydrogen in each molecule of water. How many atoms of hydrogen would there be in two water molecules? There would be 2 2 = 4 hydrogen atoms. How about in a dozen? In that case a dozen is 12 so 12 2 = 24 hydrogen atoms in a dozen water molecules. To get the answers, (4 and 24) you had to multiply the given number of molecules by two atoms of hydrogen per molecule. So to find the number of hydrogen atoms in a mole of water molecules, the problem could be solved using conversion factors. Q: H2o is the chemical formula for what? Choices: - glass - smog - salt - water A:
water