化学
化学反応、化学量論、分子構造、元素の性質。
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how many electrons are in an atom that has 32 protons?
32
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what is the difference between an element and an atom? how is an isotop…
An element is a pure substance of one - type atoms. An atom is the smallest element unit. Isotopes are same - element atoms with different neutrons.
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what determines the vast majority of characteristics in an atom?
The electrons in an atom determine the vast majority of its characteristics.
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a scientist is determining the mass of 23,000 molecules of oxygen. use …
\(2\)
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name and describe the three subatomic particles. for each particle, sta…
- Proton: Positively charged, in the nucleus. - Neutron: No charge, in the nucleus. - Electron: Negatively charged, orbits the nucleus.
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independent practice: working silently and independently, answer the fo…
The average atomic mass of boron is \(10.81\) atomic mass units. ### Question 2
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independent practice: working silently and independently, answer the fo…
The average atomic mass of boron is approximately $10.81$ atomic mass units.
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sample test item the haber process is the main industrial method for pr…
First box: nitrogen Second box: hydrogen Third box: nitrogen Fourth box: hydrogen
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instruction: read each problem carefully and balance the chemical equat…
1. \(4.00\space mol\) 2. \(3.00\space mol\) 3. \(7.50\space mol\) 4. \(10.0\space mol\)
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question 10 of 10 how does temperature affect the rate of a reaction? a…
B. Increasing the temperature gives the molecules more kinetic energy.
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what does a reaction energy diagram represent? a. the changes in the re…
D. The changes in energy during a reaction
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question 8 of 10 what is a reaction rate? a. the amount of products pro…
D. The speed at which a reaction occurs
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question 6 of 10 what does the energy hill represent on an energy diagr…
D. The additional potential energy the reactants must gain in order to react
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question 5 of 10 what makes an increase in temperature change the react…
C. It increases the collisions that result in a reaction.
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question 4 of 10 how does the concentration of reactants affect the rat…
B. Increasing the concentration increases the molecules' collision frequency.
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question 3 of 10 what is the purpose of a catalyst? a. to increase the …
C. To lower the activation energy of a reaction
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question 2 of 10 what is the activation energy of a reaction? a. the en…
A. The energy the molecules must have in order to react
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question 1 of 10 how does increasing the pressure affect the reaction r…
A. The concentration of reactants is changed
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question 10 of 10 what product of an acid - base reaction is an ionic c…
A. A salt
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question 9 of 10 which of the following is an example of a conjugate ac…
B. \(H_{2}S\) and \(HS^{-}\)
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question 8 of 10 what is a conjugate acid? a. the acid formed when a ba…
D. The acid formed when a base gains an \(H^{+}\)
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question 7 of 10 what happens in a brønsted-lowry acid - base reaction?…
B. An acid donates an \(H^{+}\), and a base accepts an \(H^{+}\)
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question 6 of 10 what happens in a neutralization reaction? a. hydrogen…
D. An acid reacts with a base to produce a neutral solution.
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question 5 of 10 what happens in a lewis acid - base reaction? a. an ac…
C. An acid accepts an electron pair from a base.
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question 4 of 10 which of the following is an example of a bronsted - l…
C. \(NH_{3}\)
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question 3 of 10 what is true of an arrhenius acid? a. an arrhenius aci…
A. An Arrhenius acid donates $H^{+}$ ions.
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question 2 of 10 what is the purpose of a buffer? a. to limit ph change…
A. To limit pH changes in solution
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question 1 of 10 which of the following is an example of a bronsted-low…
A. \(NH_4^+\)
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multiplying fractions: formative assessment solve each problem. provide…
1. \(\frac{9}{20}\) of the organic and locally sourced area is available to other vendors. 2. She should anticipate investing \(\$300\) in the production of more products.
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sep construct an explanation why is a crystal of strontium chloride (sr…
A crystal of \(SrCl_2\) is an extended structure because it consists of \(Sr^{2+}\) and \(Cl^-\) ions arranged in a repeating three - dimensional pattern (due to ionic bonding) wi…
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4. write the chemical equation for the burning of methane here:ch₄ + 2o…
a. Carbon: \(1\) (start), \(1\) (end) b. Oxygen: \(4\) (start), \(4\) (end) c. Hydrogen: \(4\) (start), \(4\) (end)
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which of the following is true? sucrose is made of one glucose molecule…
Sucrose is made of one glucose molecule and one fructose molecule.
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click to fix any plural or possessive errors below. if there is no erro…
While working in the lab, Princess Anna was careful not to touch the chemists' experiments.
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multiple - choice question \saturated fat\ is saturated with: oxygen at…
Hydrogen Atoms
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section 5.2 continued in your textbook, read about the heisenberg uncer…
10. c. quantum mechanical model of the atom 11. a. Heisenberg uncertainty principle 12. d. atomic orbital 13. b. Schrödinger wave equation 14. The Bohr model describes electrons i…
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2. a sample has a nitrate concentration of 5.42 mg/l (5.42 ppm no₃⁻). c…
$8.74\times10^{-5}\text{ mol/L}$
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which subatomic particle determines the identity of the atom?
Proton
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2. a sample has a nitrate concentration of 5.42 mg/l (5.42 ppm no₃⁻). c…
$71.25\ ppm$
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which of the following explains how scientists know that current global…
hydrochlorofluorocarbons (HCFCs); reducing the damage to the ozone layer
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which of the following is true about sulfurous smog? it exists in damp,…
1. It exists in damp, cold weather. 2. It can decrease the crop yield in a region.
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when we look at different elements, we can identify them by the number …
atomic number
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14. evaluate a friend tells you, \because composition does not change d…
No, the friend is not correct.
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particles. there are negatively charged (5)______ that can be found in …
(5) electrons (6) protons (7) neutrons
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question 2 (matching worth 4 points) match each pollutant with its sour…
Carbon dioxide - A Nitrogen oxides - D Volatile organic compounds - B Sulfur oxides - A
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12. describe the results of a chemical change. list four indicators of …
The results of a chemical change are the formation of new substances with different chemical properties. Four indicators of chemical change are: gas production, precipitate format…
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a new factory has been constructed near a large, still lake that is hom…
1. Fish at location A 2. Same at A and B 3. Same at A and B
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10. classify each change as physical or chemical. a. crushing an alumin…
a. Physical change b. Physical change c. Chemical change
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the element that we have the most of on out planet is hydrogen carbon o…
Oxygen
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8. a 10.0 - g sample of magnesium reacts with oxygen to form 16.6 g of …
The mass of oxygen that reacted is 6.6 g.
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6. from a laboratory process designed to separate water into hydrogen a…
89.4 g
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directions: for each of the following situations, determine whether or …
1. Consumption 2. Consumption 3. Government spending 4. Consumption 5. Consumption 6. Not counted as GDP (outside the U.S.) 7. Investment 8. Consumption 9. Investment 10. Consumpt…
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question 6. calculate the atomic mass of titanium. the five titanium is…
$47.88$ amu (rounded to two decimal places)
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1. what of the following determines an atom’s identity? a. protons b. n…
A. Protons
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question 5. what is the atomic mass of silicon if 92.21% of its atoms h…
$28.00$ amu
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1. what is the role of electrons within an atom? a. electrons are in th…
C. Electrons are outside the nucleus and have a negative charge
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question 4. magnesium consists of three isotopes with masses of 23.98 a…
$24.31$ amu (rounded to two - decimal places)
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aluminum and liquid bromine reaction substance before reaction after re…
The grams of bromine that reacted is 91.8 g and the grams of compound formed is 102.1 g.
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assess it! part 1 1. which of the following is a true statement? a. the…
B. The nucleus is found in the center of atoms and contains protons and neutrons D. Neutrons have a neutral charge
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question 3. nitrogen has two naturally occurring isotopes, nitrogen-14 …
Nitrogen - 14 is more abundant in nature.
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3. think about the chemical formulas you saw in the video — oxygen (o₂)…
The subscript in a chemical formula indicates the number of atoms of the element immediately preceding it.
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2. how could you tell what element it is if only a model was present?
Count the number of protons in the atomic - nucleus of the model.
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question 2. the atomic masses of elements are generally not whole numbe…
Elements have isotopes with varying masses, and atomic mass is a weighted - average of isotope masses according to their abundances, resulting in non - whole numbers.
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1. which subatomic particle changes the element’s identity?
Proton
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2. is a sample of water (h₂o) made up of atoms or molecules? most thing…
Molecules
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question 1. explain the difference between mass number and average atom…
Mass number is for a single isotope (sum of protons and neutrons, whole - number), while average atomic mass is a weighted average of all isotopes' masses (usually not a whole num…
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1. what two subatomic particles add up to make the mass?
Protons and neutrons
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look at these details from a paragraph about the same topic: scientists…
Goggles are worn to protect people's eyes during different activities.
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look at these details from a paragraph about the same topic: • touching…
Coral reefs face various threats.
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2. is a sample of water (h₂o) made up of atoms or molecules?
Molecules
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use the periodic table to answer the question. a reaction occurs that r…
$N_2$
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valence electrons quick check which statement best explains why carbon …
Hydrogen shares one valence electron with carbon, and oxygen shares two valence electrons.
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use the periodic table to answer the question. which atom generally obt…
C. chlorine (Cl)
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how many valence electrons do most stable atoms have? (1 point) one fou…
C. eight
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based on location in the periodic table, which element has chemical pro…
B. Fluorine (F)
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3. determine the mass of each of the following: a. 1 gold atom
$3.27\times 10^{-22}\ g$
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there are four sketches below. the first sketch shows a sample of subst…
Change 1: a physical change Change 2: a chemical change Change 3: impossible
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1. above is a periodic table. is a group of silver (ag) atoms a compoun…
An element
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protons: neutrons: electrons: what is the total charge? 0
0
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protons: neutrons: electrons: what is the mass number? 0
1
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what is the total charge?
-1
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protons: 10 neutrons: 10 what is the mass number? electrons: 10
20
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multiple choice 2 points the amount of sand recovered from 10g of origi…
B. 70% ### 7.
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4 multiple choice 2 points which substance(s) in the original sample is…
4. A. $SiO_2$ 5. B. No
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multiple choice 2 points which substance(s) in the original sample are …
2. B. $NaCl$ 3. C. $CaCO_3$
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prop 518 quiz complete the prop 518 quiz by october 14, 2025 at 11:59pm…
a. $SiO_2$ - compound, molecule b. $NaCl$ - compound, molecule, ionic compound c. $CaCO_3$ - compound, molecule, ionic compound
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1) which statement describes a chemical property of silicon? 1) silicon…
(1) 4) Silicon reacts with fluorine. (2) 2) Aluminum reacts with sulfuric acid. (3) 4) a compound (4) 1) The mixture is homogeneous and (5) 2) density (6) 2) mixture (7) 4) consis…
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1. how can pollution hasten or speed up weathering?
Pollution releases acidic substances that form acid rain. Acid rain chemically reacts with rocks and minerals, accelerating weathering.
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fill out the table below based on the following chemical equation. the …
The coefficients are 2 for $HgO$, 2 for $Hg$, and 1 for $O_2$. So the balanced equation is $2HgO ightarrow 2Hg + O_2$. The number of oxygen atoms before (in reactants) is 2 (from …
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3. ___ speeds up chemical weathering. 4. weathering happens ____ in hot…
3. Water 4. faster 5. cold; dry 6. temperature 7. cold; dry 8. the surface 9. larger 10. Quartz 11. mica
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fill out the table below based on the following chemical equation: xe +…
| Elements | Total # Before (reactants) | Total # After (products) | | ---- | ---- | ---- | | F | 6 | 6 | | Xe | 1 | 1 |
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fill out the table below based on the following chemical equation: xe +…
1 Xe + 3 F₂ → 1 XeF₆
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osha, the occupational safety and health administration, has notified y…
A. in compliance
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fill out the table below based on the following chemical equation: xe +…
The coefficients are 1 for $Xe$, 3 for $F_2$, and 1 for $XeF_6$.
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fill out the table below based on the following chemical equation: xe +…
$1\text{Xe}+3\text{F}_2 ightarrow1\text{XeF}_6$
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factors that affect the rate of weathering completion: write the missin…
13. Heat 14. faster 15. cold; dry 16. temperature 17. cold; dry 18. the surface 19. larger 20. Quartz; mica
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match the following reactions to the correct description: combustion, s…
$CH_4 + 2O_2 ightarrow CO_2+2H_2O$ - combustion $HCl + NaOH ightarrow NaCl + H_2O$ - double replacement $Mg+CuSO_4 ightarrow MgSO_4 + Cu$ - single replacement $2H_2O ightarrow 2H_…
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1. sketch a ball and stick diagram of a water molecule. label the atoms…
Draw a larger ball labeled 'O' for oxygen and two smaller balls labeled 'H' for hydrogen. Connect each hydrogen ball to the oxygen ball with a stick to represent the covalent bond…
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12. how can increasing the surface area of rock hasten or speed up the …
Increasing the surface area of rock exposes more of the rock to weathering agents such as water, air, and chemicals. With a larger surface area available for interaction, there ar…
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use the following image for questions 1 and 2. 1. which element will mo…
Aluminum. The reason is that elements in the same group of the periodic table have similar chemical properties, and boron and aluminum are in the same group (3A).
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heterogeneous vs. homogeneous mixture diagrams label the diagrams as ho…
1. Homogeneous 2. Homogeneous 3. Heterogeneous (two distinct types of particles) 4. Heterogeneous (two distinct types of particles) 5. Homogeneous 6. Heterogeneous (different - sh…