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Chemistry

Which scientist is known for developing the planetary model of the atom? Niels Bohr Albert Einstein Johannes Rydberg Robert Millikan

Alexa Spicer

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At construction sites, workers often reduce erosion by ____. a. moving excess sediment back to its original location c. planting trees b. spraying water on bare soil d. all of the above

Donald Ward

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What was the robotic vehicle Opportunity designed to do? A. probe beneath the moon’s surface for signs of volcanic activity B .map the contours of craters and valleys on the moon C. determine the chemical composition of rocks and soil on Mars D. measure precipitation on Mars

Craig Stewart

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Energy in an ecosystem flow from consumers to producers.True of False

Timothy Norman

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Nitrogen and hydrogen combine at high temperature, in the presence of a catalyst, to produce ammonia. . N2(g)+3H2(g)=2NH3(g). . Assume 0.280 mol of N2 and 0.884 mol of H2 are present initially.. . After complete reaction, how many moles of ammonia are produced?__________. . How many moles of H2 remain?___________. . How many moles of N2, remain?___________. What is the limiting reactant?________(nitrogen or hydrogen)

Amanda Johnson

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What is the mass in grams of 1.24 mol of water H2O ?

Craig Stewart

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The reaction below has an equilibrium constant kp=2.2×106 at 298 k. 2cof2(g)⇌co2(g)+cf4(g) calculate kp for the reaction below. cof2(g)⇌12co2(g)+12cf4(g)

Whitney Matthews

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Which statement about gases is true? A.They are made up of particles that always move very slowly. B.They are made up of particles that travel in a curved path when in motion. C.They are made up of hard spheres that vibrate quickly in stationary positions. D.They are made up of hard spheres that are in random motion.

Kaitlin Dean

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What is not true of a strong base? A. It must have a concentration above 1.0 M. B. It is always a strong electrolyte in water. C. It ionizes well in water. D. It conducts electricity in solution.

Mindee Nelson

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The production of carbon-14 _____. is caused by photosynthesis in plants occurs to a large extent in nuclear reactors is mostly due to fallout from nuclear explosions takes place in the upper atmosphere

Chelsea Hayes

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What is the best description of what Becquerel observed in his experiment? A.stable nuclei absorbing high-energy particles as they formed less stable compositions B.stable nuclei emitting high-energy particles as they formed less stable compositions C.unstable nuclei absorbing high-energy particles as they formed more stable compositions D.unstable nuclei emitting high-energy particles as they formed more stable compositions

Deborah Edwards

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Question 15 at what stage of a reaction do atoms have the highest energy? reactant stage product stage transition state stage the stage of highest energy depends on the atom.

Curtis Rhodes

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The compound FeCl3 is made of... three molecules of iron chloride. one atom of iron and three atoms of carbon. one atom of iron and three atoms of chlorine. two atoms of iodine, one atom of iron, and one atom of carbon.

Justin Parker

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Draw the acetal produced when ethanol adds to ethanal.

Theresa Perry

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What does the symbol Cp stand for?

James Washington

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Which best describes a swimming pool? 1.) it is a solute 2.) it is a solvent 3.) it is a solution 4.) it is a reactant 5.) it is a product

Jessie Thompson

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How can you tell isotopes of the same element apart?

Kevin Sutter

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Extrusions are formed by cooling magma beneath earths surface. True or False

Brandon Scott

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What did Thomson’s model of the atom include that Dalton’s model did not have?

Brandon Scott

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Explain how a global dependence on fossil fuels can lead to international security risks.

Bethany Evans

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Determine the empirical formula for a compound that is 36.86% n and 63.14% o by mass. determine the empirical formula for a compound that is 36.86% n and 63.14% o by mass. no

Kyle Mckinney

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Detergent has a ph of about 10. is detergent acidic or basic? use figure 8-3 to answer this question.

Caroline Campbell

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Under which conditions would the solubility of a gas be greatest

Kristi Hammond

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What letter represents the activation energy for the reverse reaction? Download png

Rodney Fox

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Methods scientists use to determine if a change was physical or chemical.

Curtis Rhodes

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Which of the following mixtures is NOT a colloid? Fog Milk Paint Sugar water

Amanda Johnson

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What is the oxidation number of tin (Sn) in the compound Na2SnO2? A. -2 B. 0 C. +2 D. +3

Jennifer Patterson

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Predict the chemical formula of butyne, having one carbon-carbon triple bond.

Jennifer Patterson

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Rocks formed by changes in heat and pressure or the presence of hot, watery fluids

Karen Wright

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With solutions of strong acids and strong bases, the word strong refer to ____. (1 point) normality molarity solubility degree of ionization

Timothy Norman

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What is the salt produced when sulfuric acid (H2SO4) reacts with potassium hydroxide (KOH)?a)SO4Kb)K2SO4c)KSO4d)H2O

Heather Maxwell

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What is the empirical formula of ascorbic acid, given that the pseudoformula is c3.407h4.53o3.406? express your answer as a chemical formula?

Karen Wright

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For an aqueous solution of hf, determine the van't hoff factor assuming 0% and 100% ionization, respectively. a solution is made by dissolving 0.0100 mol hf in enough water to make 1.00 l of solution. at 22 °c, the osmotic pressure of the solution is 0.307 atm. what is the percent ionization of this acid?

Jeffrey Rodriguez

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Which of these solutions has the lowest freezing point? 0.25 m nacl 0.5 m nacl 1.0 m nacl 1.5 m nacl 2.0 m nacl

Roger Moore

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Which sample, when dissolved in 1.0 liter of water, produces a solution with the highest boiling point?

Craig Stewart

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Which of the following is not an example of a physical property? a. freezing point c. reactivity b. boiling point d. density

Bethany Evans

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What type of reaction takes place when the melting of a solid occurs? combination reaction? combination reaction endothermic reaction exothermic reaction precipitation reaction combustion reaction

Ramon Kelly

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At stp, which element has a definite shape and volume?

Ross Pratt

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Which statement correctly explains the polarity of the water molecule? A. The hydrogen end of the molecule has a partial negative charge and the oxygen end has a partial positive charge. B. The oxygen end of the molecule has a partial negative charge and the hydrogen end has a partial positive charge. C. Both ends of the molecule have a partial negative charge, which attracts the other water molecule towards itself.

Ashley Howard

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Based on the sign of E cell, classify these reactions as spontaneous or non spontaneous as written.? assume standard conditions. Ni^2+ (aq) + S^2- (aq) ----> + Ni (s) S (s) (nonspontaneous)? Pb^2+ (aq) +H2 (g) ----> Pb (s) +2H^+ (aq) (nonspontaneous)? 2Ag^+ (aq) + Cr(s) ---> 2 Ag (s) +Cr^2+ (aq) (spontaneous?) Are these correct?

Jennifer Patterson

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Stellar equilibrium is balance between what two things

Donald Ward

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Which of the following statements describes a scientific law? a. A scientific law explains a set of events. b. A scientific law describes what occurs every time in a situation. c. A scientific law is constantly modified. d. A scientific law is developed without experimentation.

Mindee Nelson

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Greenhouse gases help regulate earths. A) oceans B) acid rain C) atmosphere D) temperature

Carlton Burgess

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Why is a chemical indicator added to the flask in which a titration will occur? Download png

Kyle Mckinney

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What should the IUPAC name for a binary covalent compound lack? prefixes Roman numerals an -ide ending the name of a nonmetal

Jeffrey Rodriguez

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Which of the following explain the variations in solubility for methane, ethane, and ethylene?

Theresa Perry

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Draw the acetal produced when ethanol adds to propanone.

Kyle Mckinney

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The vascular cambium _____.

Curtis Rhodes

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What is the empirical formula of a compound that contains 27.0% s, 13.4% o, and 59.6% cl by mass?

Melissa Norris

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