Chemistry 8 Precomp Diagnostic

An ionic compound is formed when... A. Hydroxide ions of a compound bond to nitrate ions in another compound B. Metal atoms of an element transfer electrons to non-metal atoms of another element C. Neutral compounds gain electrons from another compound D. Metal atoms of an element accept electrons from non-metal atoms of another element

B

Arsenic has five valence electrons. Predict the shape of a molecule of AsH3. A. Trigonal planer B. Pyramidal C. Tetrahedral D. Bent

B

If you know the atomic number of an element, what information does it give you about the neutral atoms of the element? A. The number of electrons, protons, and neutrons B. The numbers of electrons and protons C. The number of protons only D. The number of neutrons only

B

The substances in a beaker or at room temperature before a chemical reaction takes place. What do you know if you touch a beaker during the chemical reaction and it feels cold? A. The reaction is exothermic. Heat transfers from my hand to the beaker B. The reaction is endothermic. Heat transfers from my hands to the beaker. C. The reaction is exothermic. Heat transfers from the beaker to my hand D. The reaction is endothermic. Heat transfers from the beaker to my hand.

B

What are ions are present in ammonium carbonate? A. NH3+ and CO2 -2 B. NH4+ and CO3-2 C. NH4+ and CO4-2 D. NH3+ and CO2-2

B

A compound is determined to be 18.7% lithium, 16.3% carbon, and 65.0% oxygen. What is the empirical formula of the compound? A. Li3CO2 B. LiCO C. LiC2O3 D. Li2CO3

D

Cu is an example of... A. A mixture B. A compound C. A solution D. An element

D

For any given substance, which of the following phase transitions should release the most energy? A. Solid to liquid B. Liquid to solid C. Solid to gas D. Gas to solid

D

If you have one mol of aluminium, 1 mol of iron, one mol of zinc, and 1 mole of tin, which has the most mass? A. Aluminum B. Iron C. Zinc D. tin

D

A can of cola contains about 39 g of sucrose, C12H22O11. how many moles of sucrose does this represent? A. 0.11 mol of sucrose B. 8.8 mol of sucrose C. 340 mol of sucrose D. 13,000 mol of sucrose

A

How can you convert the mass of a substance to moles? A. Divide the mass of the substance in grams by its molar mass B. Divide the molar mass of the substance by the mass of the substance in grams C. Multiply the molar mass of the substance by the mass of the substance in grams D. Multiply the mass of the substance in grams by its molar mass

A

Methanol dissolves easily in water. Which is the correct explanation for this? A. Methanol is polar and water is polar, so the molecules are attracted to each other B. Methanol is nonpolar and water is polar, so the molecules are attracted to each other C. Methanol is nonpolar and water is polar, so the molecules are not attracted to each other D. Methanol is polar and water is polar, so the molecules are not attracted to each other

A

The boiling point of a sample of CH4 is much lower than a sample of HF. This is because of: A. the hydrogen bonding forces in the sample of HF B. The London dispersion forces in the sample of CH4 C. The hydrogen bonding force in the sample of CH4 D. The London dispersion forces in the sample of HF

A

The element magnesium reacts with oxygen to form magnesium oxide (MgO). What compound do you predict for the reaction of magnesium with sulphur? A. MgS B. MgS2 C. Mg2S D. MgS3

A

Use a periodic table to answer this question. Which pairs of elements would you expect to have the most similar properties? A. Germanium and silicon B. Copper and Gallium C. Nitrogen and oxygen D. Hydrogen and helium

A

What is the formula for ammonium sulphate? A. (NH4)2 SO4 B.(Am4)2 SO4 C. (NH3)2 SO4 D. (Am3)2 SO4

A

What is the mass percent due to oxygen in calcium oxide? A. 28.5% B. 39.9% C. 44.4% D. 22.2%

A

Which of the following best explains what happens in a nonpolar covalent bond? A. The bonded electrons are equally shared between the atoms B. The bonded electrons spend more time around the more electronegative atom C. An electron is given up to the more electronegative atom D. The bonded electrons spend more time around the less electronegative atom

A

Which of the following is a major factor that contributes to the shape of a molecule? A. Electron domains are separated as much as possible B. Electron domains on different atoms are attracted to one another C. Electron domains on each atom form right angles to one another D. Electron domains cannot interact with one another unless the atom has a lone pair

A

Which of these compounds will not dissolve at all in water? A. Al (s) B. CaCl2 (s) C. CuCl2 (s) D. LiF (s)

A

Which of these substances will conduct electricity if it is dissolved in water? A. RbNO3 (s) B. H20 (l) C. C10H22 (l) D. C17H36 (s)

A

Which statement describes the nucleus of an atom? A. The dense, positively charge structure found in the centre of the atom B. A particle that does not have a charge found in the nucleus of an atom C. A particle with a negative charge found outside the nucleus of an atom D. A particle with a positive charge found in the nucleus of an atom

A

What element has this electron configuration: 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6? A. Bromine B. Krypton C. Argon D. Rubidium

B

What is the chemical formula for manganese (III) oxide? A. Mn2O4 B. Mn2O3 C. MnO2 D. MnO

B

What is the formula for aluminum hydroxide? A. Al(OH) B. Al(OH)3 C. Al(OH)2 D. Al2(OH)3

B

Which of the following is true about water molecules? A. The partial negative charge is on the hydrogen atoms and there is a strong intermolecular force between the water molecules B. The partial negative charges on the oxygen atom and there is a strong intermolecular force between the water molecules C. The partial negative charges on the hydrogen atoms and there is a weak intermolecular force between the water molecules D. The partial negative charge is on the oxygen atom and there is a weak intermolecular force between the water molecules

B

Which of the following statements is true about exothermic reactions? A. All exothermic reactions produce flames B. All exothermic reactions transfer energy to the surroundings C. All exothermic reactions produce sparks D. All exothermic reactions produce carbon dioxide and water

B

Which two things should you do in the case of a chemical spill on your skin or clothing? A. Wipe it off, remove clothing B. Rinse with plenty of water, tell the teacher C. Wipe it off, rinse with plenty of water D. Sit quietly, wipe it off

B

An atom of carbon has a mass of 13 amu. An atom of nitrogen has the identical mass. How is this possible? A. Both have six protons and seven neutrons B. Both have seven protons and six neutrons C. They have different numbers of protons and neutrons D. These atoms are isotopes of one another

C

How should you treat a minor skin burn? A.use a fire extinguisher B.place it under warm running water C.place it under cold running water D.immediately cover it with a bandage

C

The atomic radius of main group elements generally increases down the group primarily because the ... A. Nuclear charge increases down the group B. Nuclear charge decreases down the group C. Number of electron shells increases going down a group D. Number of electron shells decreases going down a group

C

When water freezes into ice, which of these quantities will change? A. The number of atoms B. Its mass C. Its volume D. All of the above

C

Which of these does not readily conduct electricity? A. The human body B. Salt dissolved in water C. Pure water D. A copper wire

C

Which of these is the best description of a metal? A. Soluble in water, conductive B. Soluble in water, non-conductive C. Insoluble in water, conductive D. Insoluble in water, non-conductive

C

Which statement is true about valence electrons and core electrons? A. For main group elements, the number of valence electrons decreases by one as you move from left to right on the periodic table, while the number of Core electrons remains the same. B. A core electron is located in the outer most shell of an atom. All other electrons beside the core electrons are considered valence electrons. C. A valence electron is located in the outermost electron shell of an atom. All other electrons beside the valence electrons are considered core electrons. D. For main group elements, the number of valence electrons and core electrons remains the same as you move from left to right on the periodic table.

C

You measure the weight of one bottle cap as 5.03 g, so you calculate the weight of 100 bottle caps will be 503 g. The actual weight of 100 bottle caps is 495 g. What is your percent error? A. 8% B. 4% C. 1.6% D. 0.16%

C

Object A is heavier than Object B. Which statement is true about Object A? A.Object A occupies more space than object B B. Object A has a greater volume than object B C. Object A is larger than object B D. Object A has more mass than object B

D

Predict the shape of a molecule of dichloromethane, CH2Cl2. A. Pyramidal B. Bent C. Trigonal planer D. Tetrahedral

D

The chemical formula for the compound copper (I) oxide is Cu^2O. What is most likely to be true about the properties of copper (I) oxide, copper, and oxygen? A. All three substances have similar properties B. Copper (I) oxide has property is very similar to those of copper C. Copper (I) oxide has property is very similar to those of oxygen D. All three substances have different properties

D

The oxygen atom and the oxygen ion have the same number of protons. Which will have the bigger atomic radius and why? A. The oxygen atom will have the bigger atomic radius because it has more electron shells B. The oxygen ion will have the bigger atomic radius because it has more electron shells C. The oxygen atom will have the bigger atomic radius because it has more electron repulsion D. The oxygen ion will have the bigger atomic radius because it has more electron repulsion

D

What ion has the same number of electrons as helium? A. P3- B. Ca2+ C. K+ D. Be2+

D

What is the molar mass of aluminum carbonate to the nearest gram per mole? A. 97 g/mol B. 114 g/mol C. 207 g/mol D. 234 g/mol

D

Which of the following molecules is polar? (Draw their VSEPR structures to figure this out) A. CH4 B. CO2 C. N2 D. NH3

D

Which of these statements is true about the law of conservation of mass? A. It can be proven by measuring the amount of copper at the beginning and end of a copper cycle experiment B. It states that good laboratory techniques will help prevent the accidental loss of lab materials C. It states that small amounts of mass are always lost in the course of an experiment because of spills, measurement errors, and other factors D. It has never been proven, but it is accepted as a scientific law because of evidence from numerous experiments

D

Which statement is not a sign of a chemical reaction? A. A solid is dropped into a beaker of liquid and a gas is released B. 2 liquids are mixed in a beaker and a solid forms at the bottom of the beaker C. A solid is dropped into a beaker of liquid and an explosion occurs D. A liquid is heated on a Bunsen burner and its temperature rises

D