化学
化学反应、化学计量、分子结构与元素性质。
-
which statement about the balanced equations for nuclear and chemical c…
A nuclear equation is balanced according to mass number. A chemical equation is balanced according to the number of atoms before and after the change.
-
energy release quick check which phrase describes transmutation? (1 poi…
the conversion of an atom of one element into a different element through nuclear changes
-
energy release quick check which phrase describes transmutation? (1 poi…
the conversion of an atom of one element into a different element through nuclear changes
-
energy release quick check the element radium has a mass number of 226 …
138
-
part b in the first 22.0 s of this reaction, the concentration of hbr d…
$0.0011\ M/s$
-
predict the rate of change in the concentration of i₃⁻ (δi₃⁻/δt). expre…
$0.0105\ \text{M/s}$
-
name _ atomic structure notes hs pg 2 neutral atom a neutral atom has _…
Neutral Atom: A neutral atom has no net charge; meaning the charge is zero. In a neutral atom, the number of protons and electrons are equal. Example: Hydrogen atom (1 proton, 1 e…
-
atomic structure notes ks pg 2 neutral atom a neutral atom has _ meanin…
1. The number of protons. 2. c. Protons are positively charged, located in the nucleus
-
11 formula 0.5 points what is 146 g to mg? answer 12 fill in the blank …
11. 146000 mg 12. 2.79, 24 13. 0.30
-
consider the balanced chemical equation. h₂o₂(aq) + 3i⁻(aq) + 2h⁺(aq) →…
$- 0.00350\ \frac{M}{s}$
-
express the results of the following calculations with the correct numb…
Question 1: 3.1 Question 2: 0.548, g/mL Question 3: 296.3, K
-
consider the balanced chemical equation h₂o₂(aq)+3i⁻(aq) + 2h⁺(aq) → i₃…
The change in the concentration of $H_2O_2$ per unit time $\frac{\Delta[H_2O_2]}{\Delta t}\approx - 0.0204M/s$
-
give the correct number of significant figures for each of the followin…
0.0230 s⁻¹: 3 290 nm: amb 21.6 mL: 3 1.9500×10⁻³¹ kg: 5 0.00000745 mol: 7.45×10⁻⁶ mol 870,000,000 g (to 2 sig figs): 8.7×10⁸ g 1458.2 J: 1.4582×10³ J
-
what is the value of the following operation to the correct sig figs an…
$2.15\ g$ ### Question 9
-
give the correct number of significant figures for each of the followin…
amb 4 2 3
-
select all of the following that represent homogeneous mixtures. brass …
Brass (an alloy made of copper and zinc), Salt water
-
4. why do polymers allow the plastic bag to stretch and not leak when p…
Polymers are long chains of molecules that can move and seal around the pencil.
-
4. why do polymers allow the plastic bag to stretch and not leak when p…
Polymers are long chains of molecules that can move and seal around the pencil
-
traces of water can be removed from ethanol distillate by a. vacuum dis…
1. C. fractional distillation 2. A. lattice energy 3. D. 2 4. B. selective discharge of ions 5. A. average velocity of the molecules
-
1. when pale - yellow dinitrogen(iv) oxide is heated in a closed contai…
B. nitrogen(IV) oxide is produced.
-
15. if a heavy - metal has an unstable nucleus, the instability could b…
C. I and III only ### 16.
-
which metalloid has three valence electrons? boron arsenic silicon lith…
boron
-
the table shows columns that brenda uses for her notes on the propertie…
Only in the column for metals
-
question 7 of 15 (1 point) | question attempt: 1 of unlimited sample of…
Change 1 is: a physical change Change 2 is: a chemical change Change 3 is: impossible
-
based on their locations on the periodic table, which best compares the…
Arsenic has a more nonmetallic behavior than antimony because arsenic's atoms have fewer electron shells.
-
which lists the elements in order from least conductive to most conduct…
nitrogen (N), antimony (Sb), bismuth (Bi)
-
which element is a metalloid? selenium (se) germanium (ge) phosphorus (…
germanium (Ge)
-
for metalloids on the periodic table, how do the group number and the p…
The lower the group number, the higher the period numbers, so the metalloids are found in a diagonal moving up from left to right.
-
which statement describes a property that is unique to metalloids? meta…
Metalloids are semiconducting.
-
13. the deposition of ammonium chloride crystals on the walls of a test…
13. B. sublimation 14. D. propane
-
which property do metalloids share with nonmetals? both are gases at ro…
Both can react to form acidic compounds.
-
which groups on the periodic table contain metalloids? groups 1-2 group…
Groups 13-16
-
14. the product of decarboxylation of ch₃ch₂ch₂coona is a. propanoic ac…
14. D. propane 15. C. I and III only 16. C. fermentation
-
6. which of the following liquids is a good conductor of electric curre…
6. C. Potassium chloride solution 7. C. 0.050 g 8. B. Sodium 9. C. is a saturated hydrocarbon 10. A. Group I 11. C. double decomposition reaction 12. A. $NH_3$
-
20. which of the following substances is not a diatomic gas at room tem…
No correct option ### 21.
-
(c) arrange the following compounds in order of increasing boiling poin…
$CO_2<CS_2 < NaH$
-
under a third set of conditions, the sample depicted in c changes to th…
It depends on whether new substances are formed. If only the form or state changes (like melting, freezing, etc.), it's a physical change. If new substances are created, it's a ch…
-
scenes a - d represent atomic - scale views of different samples of sub…
Physical change
-
for each property listed, identify the type of element it describes. ve…
Very good electrical conductivity: Metal Amphoteric, able to form acidic OR basic compounds: Metalloid Gaseous at room temperature: Non - metal Solid at room temperature: Metal/Me…
-
a friend cautions you against using any household chemicals because she…
D. a red herring
-
(a) describe how the percentages of carbon and hydrogen in an organic c…
The organic compound is burned in excess oxygen. The mass of carbon - dioxide produced is measured. From the mass of carbon - dioxide, the mass of carbon in the original compound …
-
(a) describe how the percentages of carbon and hydrogen in an organic c…
(a) Burn the compound in excess oxygen. Measure mass of \(CO_{2}\) and \(H_{2}O\) produced. Calculate mass of \(C\) and \(H\) using molar - mass ratios and then percentages. (b)(i…
-
(a) the electron - configuration of carbon may be written as: 1s²2s²2pₓ…
(a)(i) See above explanation for symbols in $2p_x^1$. (a)(ii) Carbon forms four bonds to achieve octet by promoting an electron. (b)(i) Inductive effect is $\sigma$ - bond polariz…
-
3a. explain the ff. terms: (i) primary alcohol (ii) secondary // (iii) …
- (i) An alcohol with -OH on a carbon bonded to one other carbon; Ethanol. - (ii) An alcohol with -OH on a carbon bonded to two other carbons; 2 - Propanol. - (iii) An alcohol wit…
-
1. charcoal is burnt at 3.0g per second for 3 hours. calculate (i) volu…
(i) Volume of $CO_{2}$ at STP: $60480\ dm^{3}$ (ii) Number of moles of $O_{2}$ consumed at STP: $2700\ mol$ (2) (i) Source of $SO_{2}$: Burning of fossil fuels with sulfur - conta…
-
why is radioactive dating important when approximating the age of earth…
Scientists can determine the order of when rocks formed on Earth.
-
b. complete each sentence by choosing the correct word from the word bo…
1. Solution 2. Solute 3. Solvent 4. Unsaturated 5. Saturated 6. Supersaturated 7. Solubility 8. Miscible 9. Immiscible 10. Universal Solvent
-
activity: solutions a. for each of the following mixtures, identify the…
1. Solute: Sugar; Solvent: Tea 2. Solute: Oxygen; Solvent: Nitrogen 3. Solute: Zinc; Solvent: Copper 4. Solute: Ethanol; Solvent: Water 5. Solute: Iodine; Solvent: Ethanol 6. Solu…
-
activity: solutions a. for each of the following mixtures, identify the…
1. Solute: Sugar, Solvent: Tea 2. Solute: Oxygen, Solvent: Nitrogen 3. Solute: Zinc, Solvent: Copper
-
two balloons hold two different gases. the gases are held at the same p…
the mass of each gas
-
when the pressure of a gas decreases, which quantity will increase, ass…
B. V
-
read the passage from sugar changed the world. no one could have seen i…
Advances in the production of sweeteners hastened the end of involuntary servitude.
-
read the passage from sugar changed the world. we all crave sweetness, …
Sugar cane is no longer the main source of sweetness for most people
-
36. classify classify the following changes as physical or chemical cha…
a. Physical change b. Physical change c. Chemical change d. Chemical change ### 37.
-
read the passage, then answer the question that follows. no one could h…
D. It shows that sweeteners did not need to be the product of sugar plantations and slavery
-
35. compare what is the main difference betwee physical changes and che…
Physical changes do not change the substance's identity; chemical changes form new substances with different chemical properties.
-
28. identify write the chemical symbol for each of the following elemen…
28. a. Pb b. O c. Ag d. Na e. H f. Al 29. a. Carbon b. Calcium c. Potassium d. Gold e. Iron f. Copper 30. Elements: carbon, hydrogen, oxygen, nitrogen. Element with greatest propo…
-
26. identify name two methods that can be used to break down compounds …
26. Decomposition, Electrolysis 27. a. Compound b. Mixture c. Mixture d. Element
-
which of the following are diatomic elements? select all that apply. ni…
nitrogen oxygen bromine iodine chlorine
-
16. compare and contrast how are a substance and a solution similar? ho…
16. Similarity: Macro - level uniform composition. Difference: Substance is pure, solution is a mixture. 17. Filtration for insoluble solid - liquid mixtures. Distillation for mix…
-
14. explain explain the term phase as it relates to homogeneous and het…
14. In mixtures, a phase is a physically distinct part with uniform properties. Homogeneous mixtures have one phase; heterogeneous mixtures have two or more phases. 15. a. Homogen…
-
3. list what type of properties can be used to separate mixtures?
Physical properties such as size, density, solubility, boiling - point, and magnetic properties.
-
1. what is the ph of 0.25l of chicken soup? how about 0.5l? is it acidi…
1. The pH of 0.25L and 0.5L of chicken soup is approximately 5 - 6 and it is acidic. 2. The pH does not change with a greater volume of the substance as long as no acidic or basic…
-
substance 3: solide de densité volumique de 1,7 g/cm³. des solutions in…
A. Éthanol B. Solution aqueuse d'acide acétique C. Solution aqueuse d'hydroxyde de sodium D. Glycérol E. Eau pure
-
iodine dissolves in paint thinner which makes paint thinner a? polar so…
- Question 1: non polar solvent - Question 9: all of the above - Question 10: sucrose
-
nacl table salt made up of na and cl ions dissolves in water but not in…
1. C. ionic compound 2. A. non polar compound
-
question 3 what was the result of adding a base such as naoh to the buf…
- Question 3: There was minimal or almost no change. - Question 4: True - Question 5: True
-
which of these ph solutions seen in the image below shows a neutral ph?…
Water
-
which of the solutions in the image below do you think will have the lo…
A. Vinegar
-
select the matching pairs. click the bottom right arrow to go to the ne…
polar - water, paint thinner - non polar
-
a) when 2 moles of potassium carbonate and 1 mole of calcium chloride a…
a) $CaCl_2$; $K_2CO_3$ b) $K_2CO_3$; $CaCl_2$
-
2. (a) co₂ and sio₂ are both covalent compounds. explain briefly why co…
(a) CO₂ is a gas due to weak intermolecular forces in simple - molecular structure; SiO₂ is a solid due to strong covalent bonds in giant covalent structure. (b)(i) Solid, due to …
-
fill in the missing words note to students: for molar mass values, use …
$66$
-
fill in the blanks within the following statements to describe the comp…
A fat or an oil forms when one glycerol molecule reacts with three fatty acid molecules. A fat is sometimes called a triglyceride because of its three - part structure, or a neutr…
-
2. (a) co₂ and sio₂ are both covalent compounds. explain briefly why co…
$CO_2$ has weak intermolecular forces, $SiO_2$ has a giant covalent structure. ### 2. (b) (i)
-
a) when 2 moles of potassium carbonate and 1 mole of calcium chloride a…
a) $CaCl_2$, $K_2CO_3$ b) $K_2CO_3$, $CaCl_2$
-
which career is most concerned with the study of radioactive isotopes? …
B. nuclear chemist
-
place the following items in order from lowest to highest ph milk soda …
1. Lemon juice 2. Soda 3. Milk 4. Pure water 5. Baking soda 6. Oven cleaner 7. Sodium hydroxide
-
fill in the blanks to correctly complete the statements about the ph sc…
The pH scale ranges from 0 to 14. A solution of exactly pH 7 is the pH of water. pH 7, the pH of water, is a neutral pH because water releases an equal number of hydrogen ions (H+…
-
grams of potassium hydroxide are expected to be produced if 3.1 g of po…
$3.7\ g$
-
explain the ph scale by filling in the blanks on the following statemen…
The pH scale ranges from 0 to 14. Any solution with a pH below 7 is acidic. Even a small change in pH represents a large change in the proportional number of hydrogen and hydroxid…
-
differentiate between an acid and a base by properly identifying the fo…
ACID: HCl, release hydrogen ions (H+) BASE: NaOH -> Na+ + OH-, milk of magnesia, substances that take up hydrogen ions, ammonia, substances that release hydroxide ions
-
study the following phase diagram of substance x. use this diagram to a…
1. Solid 2. Sublime (change directly from solid to gas) 3. No phase change occurs
-
2. (a) co₂ and sio₂ are both covalent compounds. explain briefly why co…
$CO_2$ has weak intermolecular forces in its simple - molecular form, while $SiO_2$ has a giant covalent structure with strong covalent bonds. ### 2(b)(i)
-
indicate the answer choice that best completes the statement or answers…
1. b. The client is using too much oil for the dry scalp treatment, and excess buildup on the scalp is contributing to the dry hair. 2. d. abrasions 3. d. cleanliness and stimulat…
-
study the following phase diagram of substance x. use this diagram to a…
Liquid It will vaporize. It will freeze.
-
fill in the missing words write a balanced equation for the reaction of…
$8.44$
-
consider a reaction of combustion of methane that produces carbon dioxi…
First case: 3, 6 Second case: 0.2, 0.4
-
how did the development of the earliest idea about atoms differ from th…
It was based on the thoughts of an early philosopher.
-
which atomic model was proposed as a result of j. j. thomsons work? the…
the plum pudding model
-
which statement best describes john daltons use of creativity in his wo…
He reinterpreted and retested Joseph Proust's results.
-
distinguish the difference between and ionic bond and a covalent bond b…
1. electrical 2. share 3. attraction 4. share 5. electrons
-
fill in the blanks to explain why atoms interact. particles that carry …
1. ions 2. oppositely 3. electrons 4. stable 5. covalent
-
which scientist provided a foundation for john daltons work on the atom…
Joseph Proust
-
match each scientist to their discovery regarding the atom. dalton ruth…
Dalton - Atoms are indivisible. Rutherford - Atoms have a positive nucleus. Millikan - Electrons have a charge of - 1. Thomson - Atoms contain electrons.
-
element # protons # neutrons # electrons mass number type your answer..…
| Element | # protons | # neutrons | # electrons | Mass Number | | ---- | ---- | ---- | ---- | ---- | | F | 9 | 10 | 9 | 19 | | N | 7 | 8 | 7 | 15 | | C | 6 | 8 | 6 | 14 |
-
complete the sentences by filling in the blanks to explain how an atom …
An atom has a central nucleus. An atom has pathways about the nucleus called orbits. The shells are sometimes called energy levels. Subatomic particles called protons and neutrons…
-
which of these did your answer include? dalton used creativity to modif…
All of the above options are correct if the question is asking about scientists using creativity in their experiments. If it's a single - choice question with an implicit 'only on…
-
how many protons are in an atom of carbon - 14? helium 2 he 4.0026 boro…
6
-
how many neutrons are in carbon - 14? helium 2 he 4.0026 boron 5 b 10.8…
8