What is the oxidation number of an oxide ion?

When 92.0g of ethanol (C₂H₅OH) are vaporized at its boiling point of 78.3^oC, it requires 78.6 kJ of energy. What is the approximate molar heat of vaporization of ethanol in kJ/mol?

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What is the density of an aqueous solution that has a mass of 10.081g and 12.5mL? ____ g/mL

Which element has 16 neutrons, 15 protons, and 15 electrons?

This equation represents which type of chemical reaction?

In the formula for barium chloride, (BaCl₂), barium (Ba) is written first because it is -

Which of these laboratory techniques is best to separate a solid from a liquid to recover the liquid?

Which of these is NOT required to ensure that stock solutions are free of contamination?

Which of these values is most responsible for changing the boiling and freezing points of a solvent?

What is the name of the compound with the formula NH₄NO₃?

Calculate the number of moles of Li₃PO₄ in 2.2L of a .60M Li₃PO₄ solution.

____ moles

Equilibrium has been reached for the reaction shown. Which conclusion is correct?

If 89.6 joules of heat are needed to heat 20.0 grams of iron from 30.0oC to 40.0oC, what is the specific heat of the iron in  $\frac{J}{g^{\circ}C}$  ?

Which of the four substances on this pH scale is slightly basic?

Which element will most likely form covalent bonds with fluorine?

The physical process of evaporation involves -

How many moles of O₂ are in the chemical equation when balanced using whole numbers?

While English physicist J. J. Thomson was carrying out experiments on cathode rays, he was able to determine that the rays consisted of particles he called "corpuscles." These particles were later named -

In the Haber process, nitrogen (N₂) and hydrogen (H₂) are directly combined to form ammonia (NH₃). Which illustration contains the the stoichiometric quantities of the reactants for this reaction?

A beaker of water is placed in a large sealed jar that is attached to a vacuum pump. As air is pumped out of the jar, the water begins to boil because -

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According to the periodic table of the elements, which elements belong to the same period?

How many moles are in  $2.04\times10^{24}$  molecules of  $H_2O$ ?

What is the name of FeCl₃ using IUPAC nomenclature rules?

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An expandable container of oxygen gas has a volume of 125mL at a temperature of 25°C. What volume will the gas occupy at 55°C? ____mL

Which of these correctly describes how organic catalysts operate in biological reactions

What volume will 35.9g of hydrogen gas (H₂) occupy at STP?

When this equation is balanced, the coefficient in from of H₃PO₄ is -

Increasing the volume of a sealed container will cause the gas particles within the container to -

Each of four groups of students determined and recorded the melting point of a solid compound. If the actual melting point is 113°C, which group had the best precision?

Consider any set of three adjacent elements in the same period on the periodic table. For which characteristic is the average for the three elements always equal to the value of the middle element?

A substance has a molecular formula of C₈H₁₀N₄O₂. The empirical formula is -

What is the correct formula for diboron trioxide?

What is the name for the compound 

How many moles of carbon dioxide (CO₂) are produced when reacting 6.00 moles of butane (C₄H₁₀) in excess oxygen (O₂)

Which structure represents a nonpolar molecule?

Using only one trial to collect data in an experiment -

A common product of acid-base neutralization reaction is -

Based on the information provided in the image, which solution is a base and a weak electrolyte?

What is the half-life of Americium-242

Two electrons are shared equally in bromine (Br₂). What type of bond is represented between the bromine atoms in this Lewis structure?

A student is studying the effects of several solutions on the prevention of the browning of apples. The student used solutions having different pH values and immersed three apple slices in equal volumes of each of the solutions. Which of these is the independent variable in this investigation?

An experiment produced 0.10g CO₂ with a volume of 0.056 L at STP. If the accepted density of CO₂ at STP is 1.96 g/L, what is the approximate percent error?