Chemistry Questions and Answers

Is oxygen a metal or a nonmetal? How many valence electrons does an oxygen atom have?

How many valence electrons does lithium, with atomic number 3, have in its outer shell?

Explain why oxygen gas must be written as O2 in a chemical equation.

What is the molar mass of methane (CH4)? A. 16.05 grams B. 13.02 grams C. 49.05 grams D. 10 grams

What is the electron geometry of the nitrogen (N2) molecule?

**Question: What is the major product of the following reaction? What is the major product of the following sequence of reactions?**

The molar mass of iron oxide (Fe2O3) is 159.7g/mol. What is the correct way to write the molar mass of iron oxide as a conversion factor?

How many electrons are in a fluorine ion, F?

Calculate the number of hydrogen atoms in a 150.0 g sample of glucose (C6H12O6). Be sure your answer has a unit symbol if necessary, and round it to 4 significant digits.

What is the total number of valence electrons in the Lewis structure of CO₂? Draw a Lewis structure for CO₂. Do not include overall ion charges or formal charges in your drawing. If the species contains oxygen, do not draw double bonds to oxygen unless they are needed for the central atom to obey the octet rule.

What charge does bromine obtain when it becomes an ion?

Calculate the number of electrons, protons, and neutrons in the Argon atom whose atomic number is 18 and mass number is 40.

Fill in the blank. ____________ varies in a family on the periodic table. A. Reactivity B. Specificity

Draw the Lewis dot structure for Mg2+. Show the charge. To change the symbol of an atom, double-click on the atom and enter the letter of the new atom.

# Question: Laboratory Assignment Laboratory Techniques Desk No.- Date, lab Sec. Identify the Technique Icon, at left, for each of the Technique Icon... | Laboratory Assignment Laboratory Techniques | | | | --- | --- | --- | | Date | Lab Sec. | Name | | Identify the Technique Icon, at left, for each of the following techniques. | | | | Technique Icon | Description of technique | | | 1. | To dispense chemicals, read the label at least twice before removing any chemical from the reagent bottle. | | | 2. | Water or glycerol should be applied to the glass tubing and the hole in the rubber stopper before inserting the glass tubing. | | | 3. | A centrifuge should be balanced with an even number of centrifuges/test tubes, placed across the outer hole one another, with equal volumes of liquid. | | | 4. | The volume of a liquid or solution in calibrated volumetric glassware should be read using all-certain digits (from the labeled calibration marks on the glassware) plus one uncertain digit (the last digit that is the best estimate between the calibration marks)—that is, to the correct number of significant digits. | | | 5. | The bowl of the funnel for gravity filtration should be always less than two-thirds full. | | | 6. | To dispense a liquid from a paper, first draw the liquid into the pipet 2-3 cm above the calibration mark with a pipet bath and then use the index finger to control its flow. | | | 7. | The suction created for the vacuum filtration of a precipitate is applied with an aspirator in which the water faucet is fully open. | | | 8. | To prepare a solution, always add the solid reagent or more concentrated solution to a volumetric flask that is already approximately one-third full with solvent. | | | 9. | While dispensing titrant from a burst, the stopcock should be operated with the left hand (if right-handed) and the Erlenmeyer flask should be swirled with the right hand. | | | 10. | To heat a solid to high temperature in the absence of air, place the solid in a crucible and fully cover the crucible with the crucible lid. | | | 11. | Information on the properties and disposal of chemicals can be found in the stockroom or online from the MSDS collection. | | | 12. | A burst should be raised with several 3- to 5-mL portions of titrant before being filled. | | | 13. | Glassware is clean when no water droplets cling to the inner wall of the vessel. | | | 14. | For heating a liquid in a test tube, the test tube should be less than one-third full, moved continuously in and out of the "cool" flame at a 45° angle, mostly near the top of the liquid. | | | 15. | The volume of a liquid should be read at the bottom of the meniscus. | | | 16. | Small quantities of liquids in test tubes are best be heated (safely) in a hot water bath with the heat source being either a hot plate or a direct flame. | | | 17. | All chemicals must be properly disposed—either according to the Experimental Procedure or the laboratory institution. | | | 18. | Never place reagents directly onto the weighing pan of a balance—always use weighing paper, a beaker, or some other container. | | | 19. | A hot plate (not an open flame) is the heat source for heating or evaporating flammable liquids. | | Laboratory Techniques 4.1

What are the electron geometry and the molecular geometry of ammonia (NH3), respectively? A. Tetrahedral, trigonal pyramidal B. Tetrahedral, tetrahedral C. Trigonal planar, bent D. Tetrahedral, bent E. None of the above

Provide the Lewis structure or dot form for the nitrogen ion (N⁺).

Which of the following is the correct Lewis dot structure for the molecule fluorine (F₂)? A. F-F B. F: F C. F⁺ F⁻ D. F₂

Draw the major product of this reaction. Ignore inorganic byproducts. Assume that the water side product is continuously removed to drive the reaction toward products. Draw the product of the reaction shown below. Use wedge and dash bonds to indicate stereochemistry where appropriate. Ignore inorganic byproducts.

Cobalt, Co, has 27 electrons. Write out the entire electron configuration for cobalt using spdf notation.

Why is phosphorus oxide represented as P4O10 and not P2O5?

How many milliliters are in a milligram?

What is the molar mass of sodium nitrate, NaNO₃? A. 52.995 g/mol B. 68.995 g/mol C. 72.991 g/mol D. 84.994 g/mol

What is the formula for the following compound: Carbon tetrafluoride?

How many electrons are there in the valence shell of the O2− ion?

What is the molar mass of citric acid (H3C6H5O7)?

What is the molar mass of the compound silver chloride?

| Fill in the table for the ion of copper: | | | | | | | --- | --- | --- | --- | --- | --- | | Symbol | Ion Charge | Number of Electrons in Ion | Number of Protons in Ion | | | | Cu | | | | | |

Is density an intensive or extensive physical property? A. Density is considered an intensive property of matter because it does not depend on the amount of matter. As the mass of a substance increases, the volume will also increase proportionally. B. Density is considered an extensive property of matter because the mass and volume change for a given sample of the same substance. C. Density is considered an extensive property of matter because it does not depend on the amount of matter. As the mass of a substance increases, the volume will also increase proportionally. D. Density is considered an intensive property of matter because the mass and volume change for a given sample of the same substance.

Determine whether the following molecules are polar or nonpolar using the Lewis structures. a. Ammonia, NH₃ b. Difluoromethane, CH₂F₂

Why do ionic compounds conduct electricity when dissolved in water, but most covalent compounds do not?

What is the mass of 750 mL of water?

Which phrase best describes a metallic bond?

Which best describes combustion as it is used in the sentence? A. a violent excitement B. the explosion of several components in a motor vehicle C. a chemical reaction caused by the combination of fuel and air D. the process of burning something

Why is K+ always a spectator ion?

What is the charge of a bromine ion?

What is the empirical formula for a compound formed by fluorine and rubidium?

How do you convert between the mass and the number of moles of a substance?

When a sulfur (S) atom becomes an ion, what charge does it usually have?

What are the products of a neutralization reaction?