Answer the following question given this paragraph: Concentration is the number of particles of a substance in a given volume. When the concentration of reactants is higher, the reaction rate is faster. At higher concentrations, particles of reactants are crowded closer together, so they are more likely to collide and react. Did you ever see a sign like the one in Figure below ? You might see it where someone is using a tank of pure oxygen for a breathing problem. The greater concentration of oxygen in the air makes combustion rapid if a fire starts burning. Q: The number of particles of a substance in a given volume is known as? Choices: - frequency - range - mass - concentration A:
concentration
Answer the following question given this paragraph: Fluid friction is friction that acts on objects that are moving through a fluid. A fluid is a substance that can flow and take the shape of its container. Fluids include liquids and gases. If you've ever tried to push your open hand through the water in a tub or pool, then you've experienced fluid friction between your hand and the water. When a skydiver is falling toward Earth with a parachute, fluid friction between the parachute and the air slows the descent (see Figure below ). Fluid pressure with the air is called air resistance. The faster or larger a moving object is, the greater is the fluid friction resisting its motion. The very large surface area of a parachute, for example, has greater air resistance than a skydiver's body. Q: What two states of matter are included in the category "fluids"? Choices: - solids and gases - bacteria and gases - liquids and soilds - liquids and gases A:
liquids and gases
Q: Answer the following question given this paragraph: All combustion reactions are exothermic reactions. During a combustion reaction, a substance burns as it combines with oxygen. When substances burn, they usually give off energy as heat and light. Look at the big bonfire in the Figure below . The combustion of wood is an exothermic reaction that releases a lot of energy as heat and light. You can see the light energy the fire is giving off. If you were standing near the fire, you would also feel its heat. Q: All combustion reactions are what type of reactions? Choices: - flammable - geothermal - reversible - exothermic A:
A: exothermic
Question: Answer the following question given this paragraph: The slope of a position-time graph represents velocity. The steeper the slope is, the faster the motion is changing. Q: What does the slope of a position-time graph represent? Choices: - trajectory - direction - acceleration - velocity A:
Answer: velocity
*Question*
Answer the following question given this paragraph: Q: What type of role does cartilage play in the human skeleton? Choices: - variable - important - life saving - insignificant A:
**Answer**
insignificant
*Question*
Answer the following question given this paragraph: Atomic radius is determined as the distance between the nuclei of two identical atoms bonded together. Q: What is the distance between the nuclei of two identical atoms bonded together called? Choices: - cycle radius - bond radius - sleep radius - atomic radius A:
**Answer**
atomic radius