化学
化学反応、化学量論、分子構造、元素の性質。
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this passage describes a chemical reaction. read the passage. then, ans…
A. calcium carbonate ($CaCO_3$), D. citric acid ($C_6H_8O_7$)
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1. during a class - presentation, david used the diagrams below to expl…
a. i. The second diagram. ii. The first diagram. b. The second diagram represents an element as all atoms are identical. The first diagram represents a compound as it has two diff…
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this passage describes a chemical reaction. read the passage. then, ans…
strawberry aldehyde ($C_{12}H_{14}O_3$), hydrochloric acid ($HCl$)
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a pharmacy technician is using a counting tray to count medications, in…
B. Use a separate counting tray
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the lightness or darkness of a color shape what are the 2 types of shap…
1. The lightness or darkness of a color is called value. 2. The two types of shapes are geometric and organic.
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geometric and organic how do you create value? what is value? space wha…
1. Geometric and organic shapes are the two types of shapes. 2. Value can be defined in various ways depending on context, such as economic value (worth in terms of money), aesthe…
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which substance is a base? hcooh rboh h₂co₃ nano₃
B. $RbOH$
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draw conclusions write a conclusion that addresses each of the points b…
Claim: Check for new - substance formation. Evidence: Color change, gas production for chemical; state change for physical. Reasoning: New substances mean chemical change; no new …
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which condition must be met in order for an equation to be balanced? th…
D. The number of atoms in the reactants equals the number of atoms in the products
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the statue of liberty is made out of copper and was once shiny and copp…
C. a chemical reaction
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what else is produced during the replacement reaction of silver nitrate…
B. $2KNO_3$
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hydrochloric acid and sodium hydroxide can be combined to form sodium c…
The total mass of hydrochloric acid and sodium hydroxide will result in the same total mass of sodium chloride and water.
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to make a solution for an experiment, gunther needs to add 40 g of a so…
Heat the solution, dissolve the solute, and let the solution cool verifying nothing settled out.
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which describes a homogeneous mixture? a solvent dissolves in a solute …
A solute dissolves in a solvent to make a solution.
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which of the following solutions uses sugar as the base and tends to be…
B. Syrup
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which substance is used in lotions and cosmetics? o ammonium hydroxide …
acetic acid
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which best describes solubility? o the speed at which a substance disso…
the ability of one substance to dissolve in another
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when dissolved in water, an acid or a base breaks down into o a proton …
a positive and a negative ion.
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a solution has a ph of 2. which best describes the solution? a strong a…
a strong acid
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what ion do acids release in solution? o hydrogen o hydroxide o carbona…
A. hydrogen
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all of the following are treatments for mental health disorders except:…
B. chemotherapy
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which would increase the rate of dissolving salt into water? low temper…
C. more surface area
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which acid is naturally found in foods and can be safe to eat? o sulfur…
citric acid
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which property describes a mixture? it cannot be separated by physical …
It cannot be described by a chemical symbol or formula.
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which type of energy is found in food? a. mechanical b. kinetic c. ther…
D. Chemical
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which symbol in a chemical equation separates the reactants from the pr…
$ ightarrow$
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which balances the equation mg + o₂ → mgo? o mg + 2o₂ → 4mgo o 2mg + 2o…
$2Mg + O_2 ightarrow2MgO$ (the third option in the multiple - choice list)
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lexi is balancing equations. she is finding one equation to be very dif…
D. Atoms in the equation are already in balance.
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what are the products of the combustion of a hydrocarbon? carbon and ox…
B. carbon dioxide and water
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harvey mixes two liquids. which observation of the new mixture most lik…
a cloudy appearance
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which color combination would create a monochromatic color scheme? yell…
B. Different shades and tints of blue
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chemical a and chemical b react in an exothermic reaction. what can be …
More energy will be released from the old substance than the new substance will release to form its chemical bonds.
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which statement about biogeochemical cycles is true? a. plants are a pa…
B. Plants are a part of the nitrogen, carbon, and water cycles.
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question 5 of 10 which of these sentences describes a benefit of fracki…
C. Fracking can reduce the cost of oil obtained from other countries.
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1. explain the difference between a physical change and a chemical chan…
1. Physical change: Molecules unchanged. Chemical change: New molecules formed. 2. Analyze experiment results for patterns. Similar - similar reactions. Conclusion - Claim: Check …
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which type of reaction has the general formula of ab + cd → ad + cb? o …
replacement
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a car burns gasoline as it moves down the road. which energy transforma…
D. Chemical energy to kinetic energy and thermal energy
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which best describes a mixture? it has a single composition, and it has…
It can have different compositions, and it has a set of characteristics that does change.
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thirty grams of lead oxide and fifteen grams of ammonia react completel…
C. 45 g
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which property describes a mixture? it cannot be separated by physical …
It cannot be described by a chemical symbol or formula.
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which solution has the greatest number of hydroxide ions? o baking soda…
Baking soda, pH = 9
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which describes what will happen to the h+ when reactants form products…
$H^+$ binds with $OH^-$ to make water.
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which product contains a strong base that would most likely completely …
A. drain cleaner
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which is formed by positive ions from a base and negative ions from an …
A. salt
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carla is using a fertilizer that contains nitric acid. how is nitric ac…
A. strong acid
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what is the best definition of strategy? (1 point) a way to introduce a…
a plan for achieving something
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apple juice has a lower ph than black coffee. which best explains the r…
Apple juice has more hydrogen ions than black coffee.
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which refers to a measure of how acidic or basic a solution is? ph solu…
pH
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which would be least likely to completely dissolve in water? o hydrochl…
D. acetic acid
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which is the order of these solutions from strong acid to strong base? …
B. battery acid → stomach acid → antacid → baking soda → household ammonia
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which option is an isotope with 6 protons and 8 neutrons? (1 point) car…
carbon - 14
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analyze 1. which of the changes you observed indicated a physical chang…
1. No specific changes given, can't answer. 2. Varies by experiment, e.g., measurement errors; improve with better controls. 3. Physical: external property change. Chemical: new -…
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a nitrogen ion has a mass of 14 and a charge of +2. which subatomic par…
7 protons, 7 neutrons, and 5 electrons
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which atom would be neutral? (1 point) an oxygen atom with 8 electrons,…
An oxygen atom with 8 electrons, 8 protons, and 9 neutrons
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atomic composition quick check how is the mass number of an atom calcul…
protons plus neutrons
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erika made a mistake in her table. which best describes the mistake eri…
None of the above options are correct as written. But if choosing the most incorrect, A and B misstate key metal/non - metal properties severely.
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most metals\tmost nonmetals good conductor\tpoor conductor high melting…
The table has incorrect information about malleability and melting points of metals and non - metals.
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strontium and calcium form 2+ ions. strontium has one more shell than c…
1. Strontium and calcium form 2+ ions. - True 2. Strontium has one more shell than calcium. - True 3. Strontium has more electrons than calcium. - True 4. Strontium and calcium te…
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why is it essential to life that water has a high heat capacity? water’…
Water’s high heat capacity allows it to absorb a large amount of heat before increasing in temperature, allowing humans to maintain a steady body temperature.
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which two statements can best explain why strontium binds to bone tissu…
Strontium and calcium form 2+ ions.
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based on the information in the periodic table, how does titanium (ti) …
D. Titanium is a solid, and fluorine is a gas
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based on the information in the periodic table, how does titanium (ti) …
D. Titanium is a solid, and fluorine is a gas.
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which element behaves the most like calcium and why? k, because it is i…
Be, because it is in the same group and has same number of valence electrons.
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which element behaves the most like calcium and why? ○ k because it is …
Ba, because it is in the same group and has same number of valence electrons.
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preview each experiment you will perform. for each experiment, is the c…
To determine if a change is physical or chemical, observe for new - substance formation and signs such as color change, gas evolution, or heat changes.
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atom ion isotope - a potassium atom has equal numbers of protons and el…
The statement "a potassium ion has one less electron than protons giving it a negative charge" is incorrect. A potassium ion has a positive charge.
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why does a layer of ice form on the surface of a pond during freezing w…
Molecules of water in the solid phase are less dense than those in the liquid phase.
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atom ion isotope - a nitrogen atom has an equal number of protons, neut…
The descriptions about atom, ion, and isotope of nitrogen are correct.
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famous friday - for the following famous scientist, you must research w…
Percy Julian was a prominent chemist known for his work in synthetic steroid - based drugs. He overcame racial obstacles in science and made significant contributions to the synth…
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hands - on lab exploring physical and chemical changes all substances a…
Examples of physical changes: melting ice. Chemical changes: burning wood.
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which change would decrease the ph of a base in a solution at equilibri…
D. decreasing the concentration of $OH^-$ ions
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use the information in the table to answer the question. acid solutions…
HA, HC, HB
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hydrochloric acid is a strong acid. acetic acid is a weak acid. which s…
The dissociation constant for hydrochloric acid is greater than the dissociation constant for acetic acid.
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which acid - base chemical reaction is irreversible? (1 point) weak bas…
strong acid added to water
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pre - ap chemistry bellwork 9/5 students collect mass and volume data f…
$14.5\ g/ml$
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which three models display the structure of an atom, its ion, and its i…
The three models labeled Atom, Ion, Isotope
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question 1 - 8 why does a layer of ice form on the surface of a pond du…
Molecules of water in the solid phase are less dense than those in the liquid phase.
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which term describes when two atoms of the same element have different …
C. Isotopes
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what is the atomic number of an oxygen atom with 8 protons and 10 neutr…
8
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what does the electron cloud model describe? the group of protons that …
location where an electron has the highest probability of being found
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how many protons are in this atom if it has a balanced charge? 0 2 4 6
B. 2
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which statement best describes the electrons in this illustration? the …
The electrons are negatively charged particles located outside the nucleus
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freezing is a phase change from a ______ to a ______. a. solid; liquid …
D. liquid; solid
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select the correct answer. samuel adds a teaspoon of salt to a glass of…
B. It's a physical change because the water and the salt kept their original properties.
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select the correct answer. carbon burns in the presence of oxygen to gi…
B. carbon + oxygen → carbon dioxide
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select the correct answer. what kind of chemical reaction does the chem…
D. synthesis
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protons, neutrons, and electrons practice worksheet calculating the num…
| Name of Element | Element Symbol | Mass Number | Atomic Number | Protons | Neutrons | Electrons | | ---- | ---- | ---- | ---- | ---- | ---- | ---- | | Boron | B | 11 | 5 | 5 | 6…
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what is atomic mass? o the mass of the atom based on the mass of an ato…
the mass of an atom based on the mass of an atom of carbon-12
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in the author to her book, the main reason bradstreet uses inversion is…
complete the rhyme scheme.
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which term describes atoms with different atomic masses due to varying …
C. isotopes
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carbon has an atomic number of 6 and a mass of 12. carbon - 14 is a nat…
C. 8
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directions: using the physical properties of substances listed in the t…
First, use a magnet to separate the nickel from the mixture of water, oil, dirt and nickel. Then, let the remaining mixture settle and decant the oil layer. Finally, filter the re…
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a neutral atom of which element contains 10 electrons? a. boron b. fluo…
D. neon
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what happens to the gas when a gas is compressed and the molecules are …
It rises in temperature
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model 1 - copper samples group number volume (cm³) mass (g) substance 1…
Copper
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question 20 5 pts a poem with 14 lines that is written in a well - defi…
D. sonnet
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how does a chlorine atom become a negatively charged ion? a. it gains a…
A. It gains an electron.
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which of the following is most chemically like sulfur (s)? a. oxygen (o…
A. Oxygen (O)
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pure substances are made up of only one type of atom or compound, where…
C. milk
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on the periodic table, the elements in the columns have the same a. den…
D. number of valence electrons