化學
化學反應、化學計量、分子結構與元素性質。
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this is a soil sample. like this soil sample, most soils contain some c…
This soil sample is composed of two or more substances that can be physically separated but are not evenly distributed, so it is a heterogeneous mixture.
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this is a flask containing nitrogen dioxide gas. in the atmosphere, nit…
Nitrogen dioxide is composed of atoms of two or more different elements in a fixed ratio and can be chemically decomposed, so it is a compound.
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these are drops of mercury. mercury, a shiny silver metal, is composed …
Mercury is composed of only one type of atom and cannot be chemically decomposed, so it is an element.
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this is a bowl of white vinegar. white vinegar is a clear liquid used i…
White vinegar is composed of two or more substances that can be physically separated and are evenly distributed, so it is a homogeneous mixture.
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b. calculations b.1 calculate the number of moles of hcl added to each …
B.1: \(0.05\space mol\) B.2 a: \(\approx0.0123\space mol\) B.2 b: \(\approx0.0247\space mol\) B.2 c: \(\approx0.0494\space mol\)
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this is a dish containing iron(iii) chloride. iron(iii) chloride is use…
Iron(III) chloride is composed of two or more different ions in a fixed ratio and can be chemically decomposed, so it is a compound.
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this is magnesium ribbon. magnesium ribbon is composed of magnesium ato…
Magnesium ribbon is composed of only one type of atom and cannot be chemically decomposed, so it is an element.
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b.3 calculate the number of moles of magnesium that will react in each …
a. \(0.0123\) mol, b. \(0.0247\) mol, c. \(0.025\) mol.
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select the correct answer. what do a mole of magnesium (mg) and a mole …
A. their number of atoms
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select the correct answer. which of these is always equal to the molar …
B. its atomic weight
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select the correct answer. if the atomic weight of nitrogen is 14.0, wh…
D. 28.0 g
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select the correct answer. what is the mass, in grams, of one mole of a…
B. molar mass
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select the correct answer. if the atomic weight of nitrogen is 14.01, w…
B. 28.02 grams
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b.3 calculate the number of moles of magnesium that will react in each …
a. \(0.0123\) mol, b. \(0.0247\) mol, c. \(0.025\) mol
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b.4 calculate the number of moles of h₂ that are expected to form in ea…
a. \(0.0123\space mol\) b. \(0.0247\space mol\) c. \(0.0494\space mol\)
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q.6 for the reaction of magnesium and hcl, if you react 25 grams of mag…
The limiting reactant is \(HCl\) and the mass of \(MgCl_2\) produced is approximately \(48.3\space g\)
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b.5 normalize the number of moles of h₂ that are produced by dividing t…
a. \(0.5\) b. \(1\) c. \(2\)
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b.4 calculate the number of moles of h₂ that are expected to form in ea…
b. \(0.0247\space mol\) c. \(0.0494\space mol\)
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what do these two changes have in common? a puddle freezing into ice on…
A. Both are only physical changes.
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b.4 calculate the number of moles of h₂ that are expected to form in ea…
B.4: a. \(0.0123\space mol\) b. \(0.0247\space mol\) c. \(0.0494\space mol\) B.5: a. \(0.5\) c. \(2\) Q.4: The ratios in B.5 (0.5, 1, 2) should be directly proportional to the vol…
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what do these two changes have in common? mixing sand and gravel ice me…
A. Both are only physical changes.
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what do these two changes have in common? a dinosaur bone turning into …
Both are chemical changes.
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what do these two changes have in common? sanding a piece of wood a cra…
A. Both are only physical changes.
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when gabriel goes into starbucks, he knows how to order his favorite dr…
1. D. a scheme 2. (Since the options for question 2 are incomplete, but based on the analysis, if we assume the correct option is related to the sensorimotor stage and lack of obj…
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what do these two changes have in common? a penny tarnishing burning a …
Both are chemical changes.
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what do these two changes have in common? firing a clay pot in a hot ki…
Both are chemical changes. Both are caused by heating.
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what do these two changes have in common? erosion caused by wind water …
Both are only physical changes.
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what do these two changes have in common? chemicals in a battery reacti…
Both are chemical changes.
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9. a factory wants to produce ammonia (nh₃) as quickly as possible usin…
Increase temperature (to increase kinetic energy and rate - constant), increase pressure (to increase concentration and shift equilibrium towards products), increase the concentra…
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what do these two changes have in common? breaking a piece of glass dry…
Both are only physical changes.
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what do these two changes have in common? water boiling on a stove usin…
A. Both are only physical changes.
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this passage describes a chemical reaction. read the passage. then, fol…
| Substance | Reactant | Product | |--|--|--| | carbon monoxide (\(CO\)) | | \( \checkmark \) | | hydrogen (\(H_2\)) | | \( \checkmark \) | | methane (\(CH_4\)) | \( \checkmark \)…
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this passage describes a chemical reaction. read the passage. then, fol…
| Substance | Reactant | Product | | --- | --- | --- | | carbon dioxide ($\ce{CO2}$) | | ✔️ | | methane ($\ce{CH4}$) | ✔️ | | | oxygen ($\ce{O2}$) | ✔️ | | | water ($\ce{H2O}$) | …
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did you know that bananas are not an ingredient in most banana - flavor…
| Substance | Reactant | Product | | --- | --- | --- | | acetic acid (\(C_2H_4O_2\)) | ✔️ | | | isoamyl acetate (\(C_7H_{14}O_2\)) | | ✔️ | | isopentanol (\(C_5H_{12}O\)) | ✔️ | |…
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select the erlenmeyer flask.
The third image (the conical - shaped one with volume markings) is the Erlenmeyer flask.
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each arrow shows an electron moving from one energy level to another. w…
A and C
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violet has noticed that shes been feeling sick around one of the chemic…
Yes
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if we look at fossils and rock chemistry, we can learn about ancient cl…
Earth's climate is dynamic, and Earth has had warm and cold periods.
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burning propane heats a 712.3 g water sample from 4 to 29°c. how much e…
$74507$ (rounded to the nearest whole number)
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1. predict: ionization energy (ie) is the energy required to remove an …
As an atom's size (atomic radius) increases, its ability to hold on to its valence electrons decreases. This is because, by Coulomb's law, the force of attraction between the nucl…
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match the descriptions to the correct formula. has 21 total atoms has 3…
- \(3Na_2S_2O_3\): Has 21 total atoms, Has 3 elements, Has 9 Oxygen atoms, Has 6 Sodium atoms - \(2NaHCO_3\): Has 12 total atoms, Has 4 elements, Has 6 Oxygen atoms, Has 2 Sodium …
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should you ever directly smell or touch any chemical without asking the…
NO
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6. explore: examine other groups and periods in the periodic table to s…
- **Question 6**: Ionization energy decreases down a group and increases across a period. - **Question 7**: A larger atomic radius means the out - ermost electron is farther from …
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2. observe: choose ionization energy. ionization energy is shown by col…
Metallic character and ionization energy are inversely related.
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how many valence electrons does a neutral atom of fluorine have? 2 3 4 …
# Explicación breve: El número atómico del flúor es 9. Un átomo neutro de flúor tiene 9 electrones. La configuración electrónica es \(1s^{2}2s^{2}2p^{5}\). Los electrones de valen…
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metallic character increases/decreases metals nonmetals ar increase ie …
A. Metals - left - hand side; Nonmetals - right - hand side. B. Vertical arrow: AR increase, IE decrease. C. Horizontal arrow: AR decrease, IE increase. D. Diagonal arrow: Metalli…
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lewis dot structures (choose all that apply) show how many valence elec…
- show how many valence electrons stay with an atom - show how valence e- are shared
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how does adding a double bond reduce the number of total electrons? ins…
La segunda opción (Instead of each atom owning its own pair of electrons, the pair of electrons should be shared between the atoms, thus reducing the total number by 2 electrons) …
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how many electrons are present in a single covalent bond? 2 electrons 3…
2 electrons
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what occurs during an ionic bond? electrons are shared between a metal …
Electrons are transferred between a metal and a nonmetal.
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the octet rule can also be called the stable 8. which elements on the p…
noble gases
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in a lewis dot structure unbonded electrons are written as what? a line…
B. Dots around the symbol of the atom.
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in a lewis dot structure what is drawn to represent a covalent bond? a …
B. A straight line
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compare the freezing and boiling points of water. °f °c k freezing: ___…
Freezing: \(32^{\circ}F\), \(0^{\circ}C\), \(273.15\space K\) Boiling: \(212^{\circ}F\), \(100^{\circ}C\), \(373.15\space K\)
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who discovered that that elements had positive and negative charges? jo…
Jons Jakob Berzelius
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select the beaker. work it out not feeling ready yet? this can help: id…
The first image (the cylindrical container with volume markings and a pouring lip) is the beaker.
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select the volumetric pipette. submit work it out not feeling ready yet…
The third image.
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select the burette. submit work it out not feeling ready yet? this can …
The first image (the one with the red stopcock) is the burette.
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select the volumetric flask.
The second image (the one with a round - bottom, long narrow neck, and a single "100 mL" calibration mark) is the volumetric flask.
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select the burette. submit work it out not feeling ready yet? this can …
The second image (the long tube with a stopcock).
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select the volumetric pipette.
The first image (the pipette with a bulb and a single graduation mark) is the volumetric pipette.
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select the graduated cylinder. submit
The first image.
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select the graduated pipette. submit
The first pipette (with measurement markings along its length) is the graduated pipette.
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what is a pure substance that contains atoms of more than one element c…
- First question: a compound - Second question: solid gold - Third question: No more solute can be dissolved.
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in a solution, what is the substance that is dissolved called? solute s…
1. solute 2. solvent 3. the solute
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q.3 why is the number of moles of hcl divided by 2 when it is compared …
Because in the chemical reaction \(Mg + 2HCl = MgCl_{2}+H_{2}\uparrow\), the stoichiometric ratio of \(Mg\) to \(HCl\) is \(1:2\). Dividing the moles of \(HCl\) by \(2\) allows fo…
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b.3 calculate the number of moles of magnesium that will react in each …
a. \(0.0123\space mol\) a1. \(0.025\space mol\) b. \(0.0247\space mol\) b1. \(0.025\space mol\) c. \(0.0494\space mol\) c1. \(0.025\space mol\)
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questions and problems q.1 write the equation for the reaction of magne…
\(2\) moles of \(HCl\) are reacted with each mole of \(Mg\).
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q.1 write the equation for the reaction of magnesium with hcl. mg + 2hc…
\(Mg + 2HCl ightarrow MgCl_{2}+H_{2}\uparrow\)
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8.2 calculate the number of moles of magnesium ribbon added to each fla…
a. \(0.0123\space mol\) b. \(0.0247\space mol\) c. \(0.0494\space mol\)
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what is the primary mechanism through which freshwater mussels reduce t…
By actively filtering and removing suspended particles from the water
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what stakeholder is focused on preserving and maintaining water resourc…
- Primera pregunta: Government regulatory agencies - Segunda pregunta: It helps assess the water’s ability to support aquatic life
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for $_{38}^{85}sr$, there are 47 protons and 38 neutrons. 85 protons an…
38 protons and 47 neutrons.
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¿qué características comparten entre sí los elementos de un grupo? todo…
Todos tienen propiedades químicas y físicas similares.
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the compound mgcl₂ is named magnesium dichloride. magnesium chloride. m…
1. magnesium chloride 2. (Assuming the correct electron - dot structure with 7 dots around \(Cl\) as per the filled - in option in the image) 3. (Assuming the full option set, but…
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question 2 (1 point) which of the following represents the correct elec…
The option with the correct electron - dot structure for chlorine (assuming it is the one with 7 dots represented properly as per Lewis structure rules) # Question 3
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(each answer, 5 points) match the words with the descriptions. 1.01) __…
1.01) F. atom 1.02) C. density 1.03) G. mass 1.04) A. texture 1.05) D. length 1.06) I. area 1.07) E. volume 1.08) H. element 1.09) B. compound
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(each answer, 5 points) match the words with the descriptions. 1.01) __…
1.010) spring scale; 1.011) liter; 1.012) graduated cylinder; 1.013) meter; 1.014) meterstick; 1.015) gram
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unit 4 - challenge 4.3: the somatic nervo which type of receptor interp…
d. Chemoreceptor
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property cannot be observed until the metal and water react, and both t…
- **Chemical or Physical Property**: - Sodium reacting with water: chemical. - Table salt dissolving: physical. - Water freezing: physical. - Iron rusting: chemical. - Glass marbl…
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when water is placed in a freezer at 0°c it becomes ice. when an iron b…
- Extensive property: Mass. - Intensive property: Density. - If using 7.5 - ounce cans: Mass changes; Density stays the same.
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atomic structure practice directions: use what you learned to answer th…
1. nucleus 2. 11 3. Protons; neutrons 4. positive 5. a. Proton; c. Neutron; d. Electron 6. c. It has a negative charge and negligible mass compared to a proton. Word - Bank: Atoms…
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mass and volume are both extensive properties; they change with the amo…
- "A pot of boiling water has more energy than a cup of boiling water": extensive - "A pot of water boils at the same temperature as a cup of water": intensive - "Copper wire cond…
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3 how many molecules are in a sample of water, h2o, which has a mass of…
A. \(1.67\times 10^{24}\space molecules\)
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write the products of the following double displacement reactions. ab +…
1. \(Al_2O_3+Ba(OH)_2 ightarrow 2Al(OH)_3 + BaO\) 2. \(Mg_3P_2+Al_2(SO_4)_3 ightarrow3MgSO_4 + 2AlP\) 3. \(K_2S+Ca_3N_2 ightarrow2K_3N+3CaS\) 4. \(Ga(NO_3)_3+SrF_2 ightarrow GaF_3…
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write t for true or f for false. if false, rewrite the statement to mak…
2.16) T 2.17) T
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choose the best answer. 2.15) a compound must have different joined tog…
- 2.15: A. elements - 2.16: T - 2.17: T
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6. density calculate the density of the following substances: a) a piec…
\(0.41\ g/mL\)
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choose the best answers. 2.11) ______ a pure substance that is made of …
2.11) A. element 2.12) B. protons 2.13) C. 98; 118 2.14) A. are
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b) which changes are chemicals changes: dissolution, oxidation, melting…
Oxidation
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how many grams of molecular chlorine will be required to completely rea…
\(0.791\ g\)
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question 30 mark this question which of the following refers to a posit…
B. Cation
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choose the best answers. 2.4)____scientists use____and computers to inv…
2.4) A. supercolliders 2.5) C. protons, neutrons, and electrons 2.6) C 2.7) B 2.8) A 2.9) nucleus 2.10) electron cloud
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2.3) ______ is the philosopher whose ideas about matter were accepted f…
B. Aristotle
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question 27 mark this question under which scenario will a chemical rea…
Lowering of the activation energy by four - fold.
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question 25 which of the following particles carries a positive charge?…
Proton
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choose the best answers. 2.1) _____ what is an atom? a. the smallest pi…
2.1) A. the smallest piece that makes up matter 2.2) B. Democritus
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throughout his career, what did jean piaget study that led to his defin…
D. the growth, development, and thoughts of young children
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question 19 mark this question which of the following bonds characteriz…
Hydrogen bonds
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question 13 which of the following represents a solution with a ph valu…
Basic solution