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PRE -TEST IN CHEMISTRY
Name: Gr./Track and section:
Teacher: Date: Score:
Directions:Choose or write the BEST answer of each question.
The following statements accurately describe the types of matter based on composition EXCEPT .
An element is a pure substance that cannot be decomposed further into newer and simpler materials by any type of alteration.
The compounds follow the law of definite compositiona natural law formulated by Antoine Lavoisier.
Both elements and compounds have homogeneous systems.That is,they are single-phased materials.
Mixtures are physical combinations of materials that retain their own properties.
2. The compound XYZ2 enters a chemical reaction and forms a gaseous element Z2 and another compound XY.Assume that X is a metallic element while both Y and Z are nonmetals.
The compound XY was an ionic compound;the atom of nonmetal gained electrons.
Z2 is a diatomic gas.
Element Y in the compound XY is brittle and dull.
XYZ2 is a ternary compound composed of three chemically united element in a varying composition.
3. Assume these conditions:
I. A and B are combined physically.
II. C and D are united chemically.
III. A,B,C and D are nonmetals.
Which of the following statements is/are TRUE?
AB is a compound.
CD is a chemical formula that represents the specific types and relative amounts of components in a mixture.
CD possesses a varying composition.
AB owns a definite chemical constitution.
CD is a covalent compound and AB is a mixture.
4. Elena observes that the mixture exhibits Tyndall effect and adsorption.What is the type of the observed mixture?
5. Which of the following statements is/are TRUE about the pure substance?
A pure substance is a material composed of only one type of particle.
A substance consists a fixed composition that remains constant for only one location.
The forms of a given element that exhibit different chemical structures and various states are known as allotropes.
This type of matter can combine physically to form mixtures.
6. The following statements are true about the states of matter EXCEPT
Liquids at zero gravity assume spherical shape.
Vapor often refers to the gaseous state of liquid or solid materials at extreme conditions of both temperature and pressure.
Gases are easily compressible fluid states of matter because they can fit into a container of any size and shape.
Solid materials display rigidity;they tend to maintain the original shape when external forces are applied.
Plasma weakly responds to magnetic fields.
7. Which of the following statements describes invalidly a compound?
A pure substance composed of chemically united elements in a constant mass proportion.
A compound adheres the law of definite composition formulated by Joseph Proust.
Being a pure substance,it can be separated by mechanical means.
Its composition remains the same for all places.
8. Ashley notices that the mass of materials before and after a reaction remains the same.What scientific law must Ashley use to describe the observed phenomenon?
9. Given the list of compounds below:
N2O, NO and N2O4
What natural law is followed by the series of compounds?
10. Calcium: metal; Chlorine: .
Noble gas
Semi-metal
Alkali metal
Late transition metal
11. I am a solid,heavy,shiny,small and orange material that reacts violently with other substances and dissolves quickly in polar solvents
Which of the following sets contains both PHYSCAL AND INTENSIVE PROPERTIES?
Solubility,luster,size and color
Reactivity,luster,state and luster
Weight,size and luster
Size,luster and color
12. An acid
turns red litmus paper into blue
has a pH value that is at most 7.
tastes sour.
is a compound that forms hydrogen ions in an aqueous solution according to Arrhenius theory of ionization.
13. A scientist tests three sample by the comparing some properties.Each sample is labeled as X,Y and Z.Results are tabulated below:
Sample Can electricity pass at any state? Can it be broken into pieces Does the material decompose into simpler materials?
X Yes No No
Y No Yes No
Z Yes( for the liquid and gaseous states) Yes Yes
What can be the conclusion/s made by the scientist?
X and Y are metallic and nonmetallic elements,respectively.
Z is also an element classified as a semi-metal.
Z is an ionic compound because it conducts electricity at both liquid and gaseous states.
None of the statements is correct.
14. Alexis and Molly tabulated their measurements of the length of a papaya tree for three trials.
Trials Molly Alexis
1 23.80 cm 23.70 cm
2 23.60 cm 24.00 cm
3 23.50 cm 23.50 cm
Who is more accurate?Who is more precise?(Assume that the accepted value is 24.50 cm.)
15. Which of the following statements BEST describes the physical changes?
A change in the form of matter;the composition also alters.
The behavior of materials in a physical change is explained by the kinetic theory of matter.
In a physical change like melting and freezing,the entropy increases from initial quantity to a final amount.
Some physical alterations involve changes of some physical properties.
16. Which of the following pairs is WRONG?
Physical chemistry-concept of systems and boundaries
Analytical chemistry-carrying out tests to identify unknown substances.
Biochemistry-concept of organic compounds.
Organic chemistry-concept of hydrocarbons.
112966514478017. Find the value :
18. A copper wire has a density of about 8.00 g/cm3.Which of the following statements is FALSE about the given sentence?
The copper wire belongs to the symbolic domain.
The underlined word is an example of an element.
Its density never depends on the amount of matter present.
A copper wire is metallic and exists in the solid state.
The measurement has 3 significant figures.
19. Jane can still pump air in the party balloon even though it is already inflated.What explains this phenomenon?
Balloons look better if its size is bigger.
Balloons are made up of plastic.
The air inside the balloon is hot.
Air molecules can be compressed.
For nos. 20-26,classify each of the following statements as true or false:
20. Every mixture contains two or more free elements.
21. Every compound is a substance.
22. Every compound contains two or more elements.
23. Every mixture contains two or more compounds.
24. Every substance is a compound.
25. All mixtures are homogeneous.
26. Every mixture contains two or more substances.
27. Assume that red,blue,green and violet spheres represent the elements A,B,C and D.Which of the following particle diagrams shows a compound?
2640965155575A. B. C. D.
00
28. A solution has two parts. One is the dissolving medium, commonly known as the solvent. What is the name of the medium that actually dissolves?
Solute
Solution
Particle
Element
29. Apple juice appears to have a single phase.That is,the appearance of this sample of matter is uniform throughout all parts of this material.Select the appropriate classification of material.
Matter?Mixture?Solution
Matter?Pure substance?Element
Matter?Mixture?Heterogeneous mixture?Colloid
Matter?Pure substance?Compound?Organic chemical substance
30. Which of the following statements DOES NOT characterize a chemical reaction?
Matter is neither created nor destroyed in the cruise of a chemical reaction. In other words,it is conserved in a chemical system.
There is an rearrangement of components particles in the chemical system.That is,chemical bonds between reactant particles break and new bonds form.
The chemical change successfully occurred because colliding particles were in proper orientation and had sufficient energy below the energy barrier.
Chemical combination laws explain the chemical behavior of materials in the chemical reaction.
31. Which of the following statements is/are TRUE?
As temperature increases,the particles of a solid material become more energized than the original state.Thus, phase change from solid to liquid state,known as melting, occurs.
Boiling point is the temperature in which both vapor pressure and air pressure are in equilibrium.
At high temperature,the gas deviates from being an ideal gas.
Amorphous solids,like ice,have particles which are tightly-packed together in a non-repeating,ordered arrangement.
is a type of compound whose molecules contain a definite combination or fixed ratio of both metallic cation and hydroxide anion.
II. Convert the following measurements into the required units:
342 hectograms to centigrams
189.670 g into Mg
45 days into weeks
56.47 hours into days
7.00 moles of Au into number of atoms
851.0 mm Hg into atm.
1.530 atm into torr
7.50 yards to feet
III. Classify each material by checking their corresponding categorization of matter.
MATERIAL(S) ELEMENT COMPOUND HOMOGENEOUS MIXTURE HETEROGENEOUS MIXTURE
1. Silver 2. Water 3. Oxygen 4. Air 5. Carbon dioxide 6. Mayonnaise 7. Hydrogen sulfide 8. Gold 9. Salad 10. Diamond IV. Determine the no. of significant figures.
0.000900
308,002.110
4,123,600
56.0000000
2031200
785643219
0.5000
2013.09860
2.4 ?1042
3.0090 ? 1012
