The modern model of the atom is based on the work of one scientist over a short period of time one scientist over a long period of time one scientist over a long period of time many scientists over a long period of time.
Which statement is true about the charges assigned to an electron and a proton? Both an electron and a proton are positive. An electron is positive and a proton is negative. An electron is negative and a proton is positive. Both an electron and a proton are negative.
In the wave-mechanical model, an orbital is a region of space in an atom where there is a high probability of finding an electron a high probability of finding a neutron a circular path in which electrons are found a circular path in which neutrons are found.
What is the charge of the nucleus in an atom of oxygen-17? 0 +8 -2 +17.
Which pair of symbols represents a metalloid and a noble gas? Si and Bi As and Ar Ge and Te Ne and Xe.
Which statement describes a chemical property of iron? Iron can be flattened into sheets. Iron conducts electricity and heat. Iron combines with oxygen to form rust. Iron can be drawn into a wire.
Given the reaction: N2(g) + 3 H2(g) 2 NH3(g)
What is the mole-to-mole ratio between nitrogen gas and hydrogen gas? 1:2 1:3 2:2 2:3.
What is the percent by mass of oxygen in propanal, CH3-CH2-CHO? 10.0% 27.6% 38.1% 62.1%.
Covalent bonds are formed when electrons are transferred from one atom to another captured by the nucleus mobile within a metal shared between two atoms.
Which type of molecule is CF4? polar, with a symmetrical distribution of charge polar, with an asymmetrical distribution of charge nonpolar, with a symmetrical distribution of charge nonpolar, with an asymmetrical distribution of charge.
Which change occurs when a barium atom loses two electrons? It becomes a negative ion and its radius decreases. It becomes a negative ion and its radius decreases. It becomes a positive ion and its radius decreases. It becomes a positive ion and its radius increases.
Conductivity in a metal results from the metal atoms having high electronegativity high ionization energy highly mobile protons in the nucleus highly mobile electrons in the valence shell.
Which of these elements has the least attraction for electrons in a chemical bond? oxygen fluorine nitrogen chlorine.
Recovering the salt from a mixture of salt and water could best be accomplished by evaporation filtration paper chromatography density determination.
The average kinetic energy of water molecules is greatest in which of these samples? 10 g of water at 35°C 10 g of water at 55°C 100 g of water at 25°C 100 g of water at 45°C.
Helium is most likely to behave as an ideal gas when it is under high pressure and high temperature high pressure and low temperature low pressure and high temperature low pressure and low temperature.
At STP, the element oxygen can exist as either O2 or O3 gas molecules. These two forms of the element have the same chemical and physical properties the same chemical properties and different physical properties different chemical properties and the same physical properties different chemical and physical properties.
Which sample contains particles in a rigid, fixed,geometric pattern? CO2(aq) HCl(g) H2O(l) KCl(s).
Given the reaction at 25°C: Zn(s) + 2 HCl(aq) ? ZnCl2(aq) + H2(g)
The rate of this reaction can be increased by using 5.0 grams of powdered zinc instead of a 5.0-gram strip of zinc because the powdered zinc has lower kinetic energy lower concentration more surface area more zinc atoms.
Which statement about a system at equilibrium is true? The forward reaction rate is less than the reverse reaction rate The forward reaction rate is greater than the reverse reaction rate. The forward reaction rate is equal to the reverse reaction rate. The forward reaction rate stops and the reverse reaction rate continues.
A catalyst increases the rate of a chemical reaction by lowering the activation energy of the reaction lowering the potential energy of the products raising the temperature of the reactants raising the concentration of the reactants.
Which element must be present in an organic compound? hydrogen oxygen carbon nitrogen.
Which compound is a saturated hydrocarbon? hexane hexene hexanol hexanal.
Given the reaction: CH3-COOH + HOC2H5 <=> CH3-COOC2H5 + H2O
This reaction is an example of: fermentation hydrogenation saponification esterification.
Which of these compounds has chemical properties most similar to the chemical properties of ethanoic acid? C3H7-COOH C2H5-OH C2H5-COO-C2H5 C2H5-O-C2H5.
Given the reaction that occurs in an electrochemical cell:
Zn(s) + CuSO4(aq) ? ZnSO4(aq) + Cu(s)
During this reaction, the oxidation number of Zn changes from 0 to +2 0 to –2 +2 to 0 –2 to 0.
A voltaic cell spontaneously converts electrical energy to chemical energy chemical energy to electrical energy electrical energy to nuclear energy nuclear energy to electrical energy.
Which pair of formulas represents two compounds that are electrolytes? HCl and CH3OH HCl and NaOH C5H12 and CH3OH C5H12 and NaOH.
Hydrogen chloride, HCl, is classified as an Arrhenius acid because it produces H+ ions in aqueous solution Cl– ions in aqueous solution OH– ions in aqueous solution NH4+ ions in aqueous solution.
Which compound could serve as a reactant in a neutralization reaction? NaCl KOH CH3OH CH3CHO.
Which of these particles has the greatest mass? alpha neutron beta positron.
In a nuclear fusion reaction, the mass of the products is less than the mass of the reactants because some of the mass has been converted to energy less than the mass of the reactants because some of the energy has been converted to mass more than the mass of the reactants because some of the mass has been converted to energy more than the mass of the reactants because some of the energy has been converted to mass.
Which of these types of radiation has the greatest penetrating power? alpha gamma beta positron.