化学
化学反应、化学计量、分子结构与元素性质。
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classify each compound by the number of chlorine atoms indicated in the…
- 1 Cl atom: $\ce{HClO2}$, $\ce{LiCl}$ - 2 Cl atoms: $\ce{BaCl2}$, $\ce{CCl2F2}$, $\ce{Ca(ClO3)2}$ - 3 Cl atoms: $\ce{Cr(ClO3)3}$ - 4 Cl atoms: $\ce{CCl4}$ - 5 Cl atoms: $\ce{PCl5…
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section 2 short answer answer the following questions in the space prov…
Heterogeneous ### b. quartz
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question 13 of 39 group the elements into pairs that would most likely …
Pair 1: Li, K Pair 2: F, Br Pair 3: S, O
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identify these elements based on their locations in the periodic table.…
period 4, group 14 (4A): Ge period 5, group 12 (2B): Cd period 4, group 16 (6A): Se
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antimony has two naturally occuring isotopes, (^{121}\text{sb}) and (^{…
\( ^{121}\text{Sb} \): \( \boldsymbol{57.19\%} \) \( ^{123}\text{Sb} \): \( \boldsymbol{42.81\%} \)
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question 10 of 39 on another planet, the isotopes of titanium have the …
\(46.84\) (or more precisely \(46.8448\)) u
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neon has three stable naturally occurring isotopes. the isotopic mass a…
The average atomic mass of neon is approximately \(\boldsymbol{20.18}\) u.
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the half-life of iodine-131 is 8 days. how many milligrams of iodine-13…
A. 0.500 mg
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question 29 of 30 the emission spectrum of hydrogen is shown below. wha…
B. Light with wavelengths of 410 nm, 434 nm, 486 nm, and 656 nm is given off when electrons fall to lower energy levels.
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question 28 of 30 which quantum number represents the main energy level…
C. \( n \)
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question 26 of 30 what are most likely the values of the quantum number…
A. \( l = 0; m_l = 0 \)
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ralph claims that the author of a well-documented study on lead impacts…
a hasty generalization ### For Eloise's statement:
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how many protons, neutrons, and electrons are there in a neutral atom o…
protons: 15 electrons: 15 neutrons: 15
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the hydrogen emission spectrum is shown below. what is the energy of th…
A. \( 4.85 \times 10^{-19} \, \text{J} \)
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identify the logical fallacy described in each example. ralph claims th…
ad hominem ### 2. Jenny's Claim
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question 19 of 30 what is the value of the quantum number n for a spin-…
C. +2
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which chemical reactions are not possible according to daltons atomic t…
The reactions that are not possible are $\boldsymbol{\ce{CCl4 -> CH4}}$ and $\boldsymbol{\ce{2H2 + O2 -> 2H2O + Au}}$. So the checkboxes for $\ce{CCl4 -> CH4}$ and $\ce{2H2 + O2 -…
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5. all oxygen atoms have eight protons, and most have eight neutrons as…
The mass number is 17, and the isotope is oxygen - 17.
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sulfur tetrafluoride, sf₄, has a mass ratio of sulfur to fluorine of 1.…
The chemical formula of the unknown compound is \( \boldsymbol{SF_6} \)
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part 3 vocabulary-write out the correct numbers to complete the sequenc…
### Part 3 1. **Explanation**: - Step 1: Analizar la secuencia. "Vingt" (20), "vingt - quatre" (24). La diferencia es 4. Entonces el siguiente número es 24 + 4 = 28 ("vingt - huit…
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question 2 of 39 element x forms three different compounds with element…
compound 2: \(XY_3\) compound 3: \(XY_2\)
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in the combustion of hydrogen gas, hydrogen reacts with oxygen from the…
The mass of oxygen that reacted is \( 265.5\ \text{g} \)
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periodic table worksheet instructions: using the periodic table fill ou…
To solve the periodic table worksheet, we use the following relationships for neutral atoms: - Atomic Number = Proton # = Electron # - Mass # (amu) = Proton # + Neutron # ### Row …
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question 4 of 30 which of the following best describes an electron tran…
B. An electron gains or loses energy and moves between quantized energy levels.
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question 1 of 30 a cobalt atom has 27 protons. what number of neutrons …
C. 32
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determine the name for each of the ionic compounds from their formulas.…
s: - $\ce{Au2O3}$: Gold(III) Oxide (the system's marking as incorrect might be an error) - $\ce{NiPO4}$: If the formula is correct, Nickel(III) Phosphate; if the formula is $\ce{N…
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question 28 of 30 what must happen for ice to melt at a given pressure?…
C. Thermal energy must be transferred to the ice from its surroundings.
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question 27 of 30 at what temperatures is a reaction that has a positiv…
B. At all temperatures for exothermic reactions
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question 26 of 30 which is characteristic of an exothermic reaction? a.…
C. Material releases heat to its surroundings.
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question 4 of 24 write the nuclear symbol for the neutral atom shown. n…
\( \ce{_{12}^{24}Mg} \)
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question 25 of 30 which statement best describes what happens when ther…
B. The thermal energy is spread out by the surrounding air.
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what is the change in entropy (δ s) when an icicle melts at 2°c? a. δ s…
B. \(\Delta S>0\)
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density = mass/volume what is the density of the object? mass = 51.842 …
\( 19.2\space g/mL \) (The unit is grams per milliliters as density is mass per unit volume, so the unit should be \( g/mL \))
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question 22 of 30 which of the following choices fits in the blank to c…
D. $- T\Delta S^0$
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determine the formula for each compound from its name. lithium oxalate:…
$Li_2C_2O_4$ ### 2. Iron(III) Oxide
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the thermochemical equation for the reaction of carbon dioxide with sul…
B. It is endothermic.
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question 19 of 30 at 298 k, $\\delta h^0 = 46$ kj/mol and $\\delta s^0 …
C. 17 kJ
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question 18 of 30 what does a change in the entropy of a system indicat…
C. That the disorder of the system has changed
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question 13 of 14 determine the name for each of the ionic compounds fr…
s: $\ce{CaS}$: calcium sulfide $\ce{Au_{2}O_{3}}$: gold(III) oxide $\ce{K_{2}CO_{3}}$: potassium carbonate $\ce{NiPO_{4}}$: nickel(III) phosphate
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you need to calculate the enthalpy change ($\\triangle h^0$) of the rea…
A. \( \Delta H^{\circ} = \Delta H^{\circ}_2 - \Delta H^{\circ}_1 \)
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what type of reaction occurs without the addition of heat? a. a spontan…
A. A spontaneous reaction
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determine the number of electrons lost or gained when each atom forms a…
Be: loses 2 electrons. Se: gains 2 electrons. I: gains 1 electron. P: gains 3 electrons.
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question 15 of 30 for a phase change, $\\triangle h^0 = 31$ kj/mol and …
C. \(\triangle G = 3.1\space kJ\); nonspontaneous
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3. what is the difference between a coefficient and a subscript in a ch…
- Coefficient: A number placed before a chemical formula (e.g., \(2\) in \(2H_2O\)) to show the number of molecules/units of that substance. - Subscript: A number written below an…
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select all the true statements. the cl⁻ and br⁻ ions have the same numb…
B. The $\ce{Fe^{2+}}$ and $\ce{Fe^{3+}}$ ions have the same number of protons. D. The $\ce{K^+}$ ion is formed when a potassium atom loses one electron.
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question 13 of 30 the reaction below shows how the potential energy cha…
B. The red arrow shows that enthalpy is negative, indicating an exothermic reaction.
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question 12 of 30 for a reaction, $\\delta h = 198$ kj. for which value…
A. 396 kJ
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question 11 of 30 the enthalpy of a reaction is -1207 kj/mol. which of …
B. Exothermic
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question 9 of 14 determine the empirical formula for the compound with …
$\ce{C_{5}H_{4}}$ ### For the compound with molecular formula $\boldsymbol{\ce{H_{2}S_{2}O_{8}}}$:
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question 10 of 30 during a reaction, the enthalpy of formation of an in…
B. 180.6 kJ
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which of the elements are nonmetals? manganese iodine mercury carbon si…
iodine, carbon, selenium (the checkboxes for these elements should be selected)
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ailanthus mel-con conclusion we will use the mel-con format in this cla…
The amount of allelopathic chemicals varies in different parts of the Ailanthus plant.
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question 9 of 30 what is the change in enthalpy of the first reaction b…
C. -112 kJ
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15. the activation energy needed for a chemical reaction is determined …
A. reactant (assuming the first option is "reactant" with a typo, as the text shows "reactant" - like spelling error but contextually, activation energy is determined by reactants…
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select the pair of elements you would expect to have similar properties…
B. P and N
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question 8 of 30 for a reaction, $\\delta h^0 = 176\\ \\text{kj/mol}$ a…
B. \( T> 617\space K \)
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why is the atomic mass of iron, 55.845 amu, most similar to the mass of…
The atomic mass is the weighted average of the masses of all of the isotopes. Iron - 56 is the most abundant isotope, so the atomic mass of iron is most similar to the mass of iro…
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below boundary (safe) zone of uncertainty (increasing risk) beyond zone…
To solve this, we analyze each environmental issue based on planetary boundaries (scientific consensus on safe, uncertain, high - risk zones): ### Below boundary (safe) - **biogeo…
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question 7 of 30 what is the relationship between the enthalpy (δh) and…
C. $-\Delta H, +\Delta S$
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question 6 of 30 the diagram below shows how the potential energy chang…
D. The reaction is exothermic because the reactants are higher in energy than the products.
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question 4 of 30 the temperature of 500 ml of water is 16⁰c. what happe…
B. The temperature of the water increases because the average kinetic energy of the water molecules increases.
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8. the amount of energy needed for a reaction to occur is called (1 poi…
D. activation energy
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question 6 of 14 iron has four naturally occuring isotopes: iron-54, ir…
D. iron - 58 ### Second Sub - Question: Identify the most abundant isotope
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question 3 of 30 what is the best definition of the enthalpy of formati…
D. The energy required for a molecule to form from its elements
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what information cannot be identified if the number of protons for a ne…
number of neutrons
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what does a positive value of $\\delta g^0$ mean for a reaction? a. the…
C. The reaction is nonspontaneous.
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question 1 of 30 what does hesss law state about the total enthalpy cha…
B. It is independent of the reaction pathway.
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question 4 of 14 write the nuclear symbol for the neutral atom shown. n…
\( \ce{^{24}_{12}Mg} \)
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4. chemical reactions and enzymes - match the following term to the cor…
- Activation Energy: b. The amount of energy that needs to be absorbed for a chemical reaction to start. - Catalyst: e. A substance that decreases the activation energy needed to …
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what is the conjugate acid of hso₄⁻ in the reaction below? h₂so₄(aq) + …
D. \( \text{H}_2\text{SO}_4 \)
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classify each statement about subatomic particles as true or false. tru…
To solve this, we analyze each statement based on subatomic particle properties: ### 1. "Protons and electrons have approximately the same mass." - Protons have a mass of ~\(1.67 …
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1. chemical reactions that absorb more energy than they release are cal…
B. Endothermic (assuming the options are labeled with B for endothermic as per typical multiple - choice setups; adjust label if needed based on actual option numbering)
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question 31 of 32 which factor(s) will most likely lower the activation…
D. Catalysts
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1. what element is present in all organic molecules? (1 point) ○ carbon…
A. Carbon.
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how do changes in temperature affect the rate of a reaction? a. changin…
C. Increasing temperature increases the reaction rate because the particles move faster and collide more often.
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which of the following is a property of both acids and bases? a. they f…
A. They form solutions that conduct electricity.
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question 28 of 32 how does the rate of a reaction change after a cataly…
C. The rate increases.
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determine which statements are consistent with daltons atomic theory. c…
Consistent: - All matter is made of atoms; atoms cannot be divided or destroyed. - Atoms of one element cannot be converted into atoms of another element. - Chemical reactions com…
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the ph of a carbonated drink is 3.0. what is the hydrogen ion concentra…
D. $1\times 10^{-3}\ M$
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carbon can react with hydrogen to form several different compounds. two…
The mass ratio of carbon to hydrogen in methane is 3:1. The mass ratio of carbon to hydrogen in ethylene is 6:1.
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question 26 of 32 the table below gives the equilibrium concentrations …
D. \( 1.7\times 10^{-3} \)
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which compound is a base? ○ a. hcn ○ b. naf ○ c. (ce{ca(oh)2}) ○ d. (ce…
C. $\ce{Ca(OH)2}$
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question 24 of 32 which of the following tends to decrease the rate of …
A. Using a less concentrated reaction mixture, C. Using larger particles of the solid reactant
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question 23 of 32 the equilibrium concentrations for the reaction betwe…
D. \( K = 1.3 \times 10^4 \); product favored
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question 22 of 32 a solution of ammonia nh₃(aq) is at equilibrium. how …
C. $[\ce{NH_{4}^{+}}]$ and $[\ce{H^{+}}]$ would decrease.
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question 21 of 32 the acid dissociation constant, ( k_a ), of ( \text{h…
C. \( \ce{HNO_3} \) is a weak acid.
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a mixture of reactants and products for the reaction shown below is at …
B. More \( \ce{NH3} \) would be produced until a new equilibrium position was reached.
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question 19 of 32 a solution of carbonic acid, h₂co₃(aq), is at equilib…
D. More \(H^+\) and \(HCO_3^-\) would be produced.
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question 18 of 32 which of the following increases the h⁺ concentration…
C. An acid
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the ph of a solution is measured as 4.5. what is the hydrogen ion conce…
A. $3.2\times 10^{-5}\ M$
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arrange the steps for determining the density of the metal slugs using …
First step: Weigh and record the mass of a clean 50 mL graduated cylinder. Second step: Add between 15 mL and 20 mL of water to the graduated cylinder. Record the volume of water …
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what does the red line in the diagram below represent? diagram: potenti…
C. The potential energy of the reactants
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question 15 of 32 what is the equilibrium expression for the reaction b…
A. \(\frac{[\text{CO}_2]}{[\text{O}_2]}\)
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question 14 of 32 the reaction below is at equilibrium. what would happ…
B. The equilibrium position would remain the same.
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what is the ph of a $1.0 \\times 10^{-4} m$ koh solution? $\\bigcirc$ a…
A. 10
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arrange the steps for determining the density of a liquid using a gradu…
First step: Weigh and record the mass of a clean 50 mL beaker. Second step: Measure 5.0 mL of the liquid in a 10 mL graduated cylinder. Third step: Pour the liquid from the gradua…
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question 12 of 32 what is the equation for the acid dissociation consta…
C. \( K_{a} = \frac{[\text{H}_3\text{O}^+][\text{F}^-]}{[\text{HF}]} \)
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when determining the density of acetone, you measure out several aliquo…
5
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question 11 of 32 which statement best describes a weak base in solutio…
C. The base dissociates slightly.
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question 11 of 11 when determining the density of acetone, you measure …
10