100 likes | 327 Views
Week 7. 1. Which formula represents a molecule?. CO 2 Ca C Co. 2. Which of these statements is true?. The particles in a mixture are from the same element. The particles in a solution can be seen in bright light. The particles in a mixture can be separated only by chemical means.
E N D
Week 7 1. Which formula represents a molecule? CO2 Ca C Co
2. Which of these statements is true? • The particles in a mixture are from the same element. • The particles in a solution can be seen in bright light. • The particles in a mixture can be separated only by chemical means. • The particles in some mixtures can be separated by filtration.
3. An unknown substance consists of particles that are different colors and sizes and are unevenly distributed throughout the substance. This is • an element. • a compound. • a mixture. • a solution.
4. Which of these statements about mixtures is false? • A mixture is made up of two or more pure substances. • A mixture can be separated by physical means. • One of the substances in a mixture must be a liquid. • A mixture does not have a definite makeup.
5. Which of the following is an example of a chemical change? • Water evaporating • Carbon joining with oxygen to form carbon dioxide • Ice cream melting • Salt dissolving in water to form a solution.
6. What happens to the temperature of a solid as it melts? • It stays the same. • It increases. • It decreases. • It increases and then decreases.
7. The elements sodium and chlorine produce the compound sodium chloride by • Melting together. • Evaporating together. • Combining physically. • Combining chemically.
8. Which property of aluminum makes it a suitable metal for soft drink cans? • It has good electrical conductivity • It can be hammered into a thin sheet (malleability) • It can be drawn into long wires. (ductility) • It can reflect light (shininess)
9. A student completely dissolves some salt in a beaker of water. Which of these statements does NOT describe the salt and water? • It is a mixture. • It is a solution. • It is a compound. • It is homogeneous.
10. What two quantities must be known to calculate the density of a sample of matter? • Color and mass • Mass and volume • Length and mass • Solubility and mass