化學
化學反應、化學計量、分子結構與元素性質。
-
10 multiple choice 1 point what is the purpose of adding anhydrous sodi…
C. To remove water from the organic layer
-
multiple choice 1 point what is the reason for using a separatory funne…
To separate the aqueous and organic layers
-
multiple choice 1 point which property of caffeine allows it to be sepa…
C. Caffeine is non - polar and more soluble in dichloromethane than in water
-
multiple choice 1 point how can the purity of the isolated caffeine be …
B. By measuring its melting point
-
multiple choice 1 point how can you avoid loss of caffeine during the e…
D. By carefully draining the layers and avoiding spills
-
multiple choice 1 point why is caffeine considered non - polar? because…
Because its molecular structure allows it to dissolve in non - polar solvents like dichloromethane
-
multiple choice 1 point which solvent is typically used for the liquid …
D. Dichloromethane (DCM)
-
3 multiple answer 1 point the techniques used in the isolation of caffe…
A. Extraction, C. Filtration, D. Recrystallization
-
2 multiple choice 1 point which of the following contaminants may co - …
B. Tannins
-
pre - lab quiz 6 answer all questions 1 multiple choice 1 point what is…
To neutralize the acidic compounds
-
which correctly lists the three layers in which water moves easily? roc…
soil, rock, organic layer
-
section 2 electric current standards check ps 3a energy is a property o…
A potential difference (voltage) creates an electric - field that exerts a force on the electrons, making them move.
-
fifty word summary write a paragraph using 50 words or fewer to summari…
Chemical potential energy is stored in substances and involved in chemical reactions, as shown by lesson evidence.
-
predict the equilibrium concentration of ca²⁺ in the reaction described…
The equilibrium concentration of $Ca^{2 + }$ is $2.7\times10^{-2}\ M$.
-
read the sentence and answer the question. to complete the lab successf…
Combine elements to form a new compound
-
4. sep construct explanations describe and explain the trend in the mel…
The melting point of the listed hydrocarbons increases as the number of carbon atoms in the molecule increases due to the increase in molar mass and the strength of London - dispe…
-
experiment 4: empirical formula of a compound name: brooklynn fera date…
1. Moles of Zn: $n_{Zn}=\frac{0.00299327\ g}{65.38\ g/mol}\approx4.58\times10^{-5}\ mol$; Moles of Cl: $n_{Cl}=\frac{0.761709869\ g}{35.45\ g/mol}\approx0.0215\ mol$ 2. Molar rati…
-
select the correct answer. which type of property can be observed only …
D. chemical property
-
select the correct answer. a 46.9 gram sample of a substance has a volu…
C. hafnium
-
drag each tile to the correct location. which type of change does the s…
Physical Change: There is no change in the chemical properties of the substance, Particles retain their composition and identity. Chemical Change: Particles rearrange into new com…
-
select the correct answer. in an experiment, lydia added 50 grams of su…
A. A physical change took place during this experiment
-
question 16 (multiple choice worth 5 points) (03.05r mc) a molecule has…
C. Linear
-
question 15 (multiple choice worth 5 points) (03.01r mc) the diagram sh…
14
-
a student described two properties of a substance as shown. property de…
D. Both are physical properties.
-
question based on the diamondene article, how does diamondene differ fr…
Diamondene is only two atoms thick.
-
please review this multimedia presentation and then answer the question…
False
-
at equilibrium, a 1.0 l reaction vessel contains 2.3 mol of mg(oh)₂ and…
$6.23\times 10^{-10}\ M$
-
question 13 (multiple choice worth 5 points) (02.05r lc) which of the f…
C. Electrons in the orbit closest to the nucleus have the least amount of energy.
-
please review this multimedia presentation and then answer the question…
Latent - Means Hidden Dipolar - The molecule has an opposite electric charge at each end Heat Capacity - The ability to absorb and store heat
-
question 11 (multiple choice worth 5 points) (03.03r mc) what is the fo…
C. $MnO_2$
-
please review this multimedia presentation and then answer the question…
C. The negative ends of the water molecule attract the positively charged sodium ions D. The positive ends of the water molecule attract the negatively charged chloride ions
-
please review this multimedia presentation and then answer the question…
Positive charge
-
application questions 1. when 0.519 g of pure sulfur (s) is allowed to …
The empirical formula of the gaseous product is $S_5F_2$
-
your company wants to understand how customers feel about their product…
1. B. A focus group 2. A. True
-
match each term to its correct definition. terms: 1. property 2. substa…
1. C 2. F 3. B 4. D 5. E 6. A
-
the farther the nucleus is from the electron, the the electronegativity…
- The farther the nucleus is from the electron, the lower the electronegativity. - As you go down a group of elements, the electronegativity decreases. - Electrons are attracted t…
-
at equilibrium, a reaction vessel contains 4.50 atm of br₂ and 1.10 atm…
$0.064$ atm
-
ionic size: the size of ions ions are formed when you either add or rem…
- Ionic Size: - electrons - cation - smaller - protons - anion - larger - more - more - Ionization Energy: - Outer - easier - more - nuclear charge; electron - electron repulsion …
-
21. your teacher presents you with an unlabeled sample of an element. w…
conductivity test
-
select the correct answer. nitrogen (n) and hydrogen (h) react with eac…
B. 1 to 3
-
20. elements in a group of the periodic table are described below. some…
D. Alkali metals
-
19. based on their location in the periodic table, which of the followi…
carbon and silicon
-
18 lead is known to contain three isotopes: 23.5% of the sample has a m…
$206.9$
-
we can read the periodic table by atomic number, atomic mass and chemic…
- Electron - shells; nuclear charge - Period - Down - Across (left to right) - Repulsion; atomic radius - Protons - Right across a period - Down a group - Down; left - Across (lef…
-
17 the diagram below shows part of dmitri mendeleevs original periodic …
Gallium (Ga), because it has chemical properties similar to those of aluminium (Al), and germanium (Ge), because it has chemical properties similar to those of silicon (Si)
-
select all the correct answers. which of these are examples of chemical…
A. removing seed coatings from grains B. a soda bottle bubbling when it is opened D. removing salt from seawater
-
elements in the periodic table are arranged in many different ways. for…
1. groups; chemical 2. electron - shells; nuclear charge; atomic; down; across (left - to - right); shells; atomic radius; protons; left; down; down; left; up; right; Francium (Fr…
-
put the words in the right order to describe the noun. the experiment s…
the successful chemistry experiment
-
question 4 2 pts what significance do these two images have for the his…
There appears to be an optical device introduced in the interim between these guys.
-
11. calcium phosphate, ca₃(po₄)₂, has a molar mass of 310.174 g/mol. de…
19.97%
-
question 10 - 1 point which of the following would be included in the n…
D. Dichloro
-
match the chemical reactions with their properties. neutralization comb…
- The reaction has at least two reactants and one product. → synthesis - The reaction has one reactant and at least two products. → decomposition - Oxygen is one of the reactants,…
-
question 9 · 1 point the simplest organic compounds contain only two el…
Carbon and hydrogen
-
question 8 · 1 point which of the following molecules is an alkene? sel…
None of the above
-
question 7 · 1 point how are hydrogen atoms represented in an alkane sk…
Hydrogen atoms are not drawn
-
3. an electrically neutral atom consists of 14 neutrons, 13 electrons, …
Aluminum (Al)
-
identify the structure with the name 4 - chlorotoluene. select the corr…
The third structure (with $CH_3$ and $Cl$ on the benzene ring in a para - relationship)
-
select the correct answer. in a given chemical reaction, the energy of …
A. Energy is absorbed in the reaction
-
select the correct answer. katie starts a key into her car ignition. sh…
C. chemical energy
-
question 5 · 1 point what is the name of the compound shown? ch₃ - ch₂ …
B. 3 - Octyne
-
question 4 - 1 point the molecular formula c₅h₁₀ can refer to which of …
D. All of the above
-
question 3 · 1 point what is the name of this molecule: ch₃ - ch₂ - ch₂…
B. 1,2 - Dichloropentane
-
does energy level 2 have a d sub shell? no yes
No
-
which subatomic particles are inside of the atoms nucleus? proton and e…
C. neutron and proton
-
the image shows the combustion of methane. which equation represents th…
E. $CH_4 + 2O_2 ightarrow CO_2 + 2H_2O$
-
which of the following is not present in skeletal structures? select th…
D. A and B
-
which of the following is going across the periodic table? group period
B. Period
-
drag the tiles to the correct boxes to complete the pairs. identify the…
- Michael uses a car that burns fossil fuels. → combustion reaction - Alan grows tomatoes on his farm. → photosynthesis - Lisa eats eggs for breakfast. → respiration
-
question 1 · 1 point identify the correct statement about types of bond…
They are more often ionic bonds.
-
identity the structure of benzene. select the correct answer below:
both A and B
-
drag each tile to the correct location. classify the chemical equations…
Balanced: $2CO + 2NO ightarrow2CO_2+N_2$, $H_2CO_3 ightarrow H_2O + CO_2$ Not Balanced: $6CO_2 + 6H_2O ightarrow C_6H_{12}O_6+O_2$, $2Cu+O_2 ightarrow CuO$
-
select the correct answer from each drop - down menu. the chemical name…
First drop - down: silicon Second drop - down: oxygen
-
question fill in the atoms or groups to complete the chemical structure…
Starting from the top - left box: $-CH_3$, adjacent right box: $-NO_2$, bottom - left box: $Cl$
-
which of these settles into layers? element suspension colloid solution…
1. B. suspension 2. C. Solids 3. D. Compound
-
identify the structure with the name 3 - bromotoluene. select the corre…
The third option (the one with a $CH_3$ group and a $Br$ on the benzene ring in the correct relative position)
-
select the correct answer. which law represents a balanced chemical equ…
C. law of conservation of mass
-
question name the aromatic compound with the following structure: selec…
methylbenzene
-
1 multiple choice 1 point which of these is an element? oxygen salt oil…
1. oxygen 2. tea
-
question what is the name of this molecule? ch₃c≡cch₂ch₂ch₃ select the …
A. 2 - hexyne
-
a newly licensed nurse is reviewing the american nurses associations co…
The nurse supports the autonomy of a client who refuses chemotherapy, even though their family wants it.
-
question which of the following is the molecular formula for the simple…
C. $\mathrm{C_2H_2}$
-
question in the molecule below, which carbons have bond angles of 180°?…
4, 5
-
reactivity of unknown elements reactivity ranking consider the reactivi…
Element E < Element G < Element F < Element H
-
6 name: molecule to be built\thint\tmolecular sketch or a screenshot of…
Hydrogen gas ($H_2$): 1. 2 H atoms 2. 1 bond per H atom Oxygen gas ($O_2$): 1. 2 O atoms 2. 2 bonds per O atom Nitrogen gas ($N_2$): 1. 2 N atoms 2. 3 bonds per N atom Ammonia gas…
-
question in an alkyne, the bond angles surrounding the carbons particip…
D. $180^{\circ}$
-
select the correct answer. which statement about polymers is true? a. p…
A. Polymers are substances that have relatively large molecules.
-
question what is the condensed formula notation for 4 - decyne? select …
A. $\mathrm{CH_3CH_2CH_2C\equiv CCH_2CH_2CH_2CH_3}$
-
question an example of an alkene is: select the correct answer below: ○…
CH₂=CHCH=CH₂
-
question how many total isomers are possible for an alkene with the mol…
4. Option Text
-
question which of the following are true of alkenes? (select all that a…
They contain at least one $sp^{2}$ hybrid orbital., They are unsaturated hydrocarbons., The bond angles in some of their carbon chains are $120^{\circ}$.
-
question which of the following is an alkene? select the correct answer…
CH₂=C(CH₃)−CH₂−CH₃
-
question what is the name of this molecule: ch₃ - ch₂ - ch(ch₃) - ch(ch…
D. 2,3 - dimethylpentane
-
question what is the condensed formula notation for 3 - ethyl - 4 - met…
B. $\mathrm{CH}_{3}-\mathrm{CH}_{2}-\mathrm{CH}(\mathrm{CH}_{2}\mathrm{CH}_{3})-\mathrm{CH}(\mathrm{CH}_{3})-\mathrm{CH}_{2}-\mathrm{CH}_{2}-\mathrm{CH}_{2}-\mathrm{CH}_{2}-\mathr…
-
question what type of alkane does not follow the cₙh₂ₙ₊₂ formula? selec…
C. Cyclic alkanes
-
video topic 2 - hde chemistry & physics: history of the atom 1. what ye…
1. 1803 2. Solid - sphere model 3. Cathode rays 4. Discovery of the electron 5. Thin gold foil 6. Atom has a small, dense, positively - charged nucleus 7. Orbiting electrons shoul…
-
question choose the options below that are not characteristics of alkan…
- Linear alkanes have the molecular formula $\mathrm{C}_{n}\mathrm{H}_{2n}$. - They have delocalized alternating carbon - carbon single and double bonds.
-
which characteristic belongs to non - metal elements? low melting point…
low melting point
-
a baker stirs sugar, butter, flour, and salt together to make dough to …
A. A mixture
-
question a linear alkane with 10 hydrogen atoms contains how many carbo…
4
-
what type of element conducts both heat and electricity and is malleabl…
B. Metal