Chapter 3 Unit Review1. You have a 78 g sample of a compound of which 12.4 g is hydrogen. What is the % by mass of hydrogen in the sample?

2. A sample is made-up of 1 g hydrogen and 19 g fluorine. What is the % by mass of hydrogen in the sample.

3. A 85 g sample of metal is dropped into a graduated cylinder causing the water level to move from 45.2 to 52.4 ml. What is the density of the metal?

4. When 3.5 g of X reacts with 10.5 g Y to form a compound of XY, what is the % by mass of X in this sample? What is the % by mass of Y is this sample?

5. Two different compounds made up of the same elements but is different proportions, (different masses) is governed by what Law:

ans: Law of Multiple Proportions

6. Given two compounds. Compound one has 15g hydrogen and 120 g oxygen. Compound two has 2 g hydrogen and 32 g oxygen. Are the two compounds the same?

7. You have a sample compound made up of 18.06 g magnesium and 6.96 g oxygen, what is the % by mass of oxygen in the sample?

8. Compound one: 4.82 g carbon and 6.44 g oxygen. Compound two: 20.13 g carbon and 53.7 g oxygen. What is the ratio of the 2 compounds?

9. Compound one: 6.46 g lead and 1 g oxygen. Compound two: 68.54 g lead and 28.76 g oxygen. Are the two compound the same?

10. Compound one: 5.753 g chlorine and 9.248 g fluorine. What is the % by mass of chlorine? What is the % by mass of fluorine?

11. Given 20 g sample of sucrose. 8.44 g carbon, 1.30 g hydrogen and 10.26 g oxygen. What is the % by mass of each element?

12. Given a 500 g sample of an unknown that contains 32.5 g hydrogen, 256.5 g oxygen and an unknown amount of carbon. Is the compound sucrose? Look at #10.

13. Given N2 + 3H2 2NH3 with 28 g nitrogen and 6 g hydrogen, what is the mass of NH3 ?

Any additional problems?

14. Are the following physical or chemical properties?Conducts electricityBoils at 85oCColorlessRemains unchanged when reacting with oxygenLiquid at room temperatureCondensingVaporizingExplodingFermentationTarnishingGrinding

15. Are the following heterogeneous mixtures or homogeneous mixtures?Alloy wheelsSalad dressingPizzaAirSalt waterBloodConcrete mix

16. Identify each as true or false:Solids have a defined shape and volume?Density for the same matter is always the same?Density is an extensive physical property?Transfer of energy indicates a chemical change?Latex paint is a heterogeneous mixture?Solutions are all homogeneous mixtures?Water contracts when heated?Gas production indicates a physical change?

17. Is it a chemical or physical change when ice melts to water?

ans: physical18. Is mass and length of an object intensive or extensive physical properties?

ans: extensive19. Is energy in or energy out required for a liquid to freeze?

ans: energy out

20. Is distillation a chemical or physical changing process?

ans: physical21. What is the physical state of matter that has a defined volume with no defined shape?

ans: liquid22. The separation of a mixture by passing the mixture through a semi-permeable membrane is called ______________

ans: filtration

23. Matter is neither created nor destroyed but can change in form, is what Law?

ans: Law of the Conservation of Matter24. The combination of two or more elements is called a (n) :

ans: compound25. A gas that normally exists as a liquid at room temperature is called a(n) :

ans: vapor

26. Two elements combine in a fixed ration by mass is called:

ans: Law of Definite Proportions27. Different compound can be formed from the same elements in different proportions by mass as long as the ratio between the two compounds are a small whole number?

ans: Law of Multiple Proportions28. Matter that has a uniform and unchanging composition is

ans: homogeneous or a solution

Solution = solute + solvent29. True or False: The stuff that is being dissolved in a solution is called the solute.

ans: true30. True or False: An alloy is a solid solution or homogeneous mixture made up of several metals.

ans: true31. The stuff the is doing the dissolving in a solution is called the _______________.

ans: solvent

32. What type of change occurs with a change in state (like water solid liquid gas)

ans: physical change33. True or False: Suspension are like muddy water where the solid will settle out if allowed to set.

ans: true34. Which has the higher kinetic energy: liquids; gases; or solids

ans: gases