Chemistry
Chemical reactions, stoichiometry, molecular structures, and element properties.
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3. sodium chloride can be made by reacting sodium metal with chlorine g…
- Sodium chloride is a substance. - Sodium chloride is a compound. - Sodium chloride is composed of two elements.
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which describes an alkaline solution? ○ ph less than 7 ○ ph equal to 7 …
C. basic
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the charged particles in the beams that thomson studied came from atoms…
C. An atom’s smaller negative particles are at a distance from the central positive particles, so the negative particles are easier to remove.
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a solution containing hcl would likely have ○ a high ph and a low poh. …
B. a low pH and a high pOH.
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1. which diagrams represent a compound? each color represents a differe…
The first (top - most) diagram (with blue and red touching circles) and the second diagram (with blue and white touching circles) represent compounds. If we consider the checkboxe…
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what is the ph of a solution with h⁺ = 1.25 × 10⁻¹⁰ m? use ph = -logh₃o…
9.90
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based on the definition of logarithms, what is the difference in hydrog…
A. A substance with a pH of 2 has a 10 times higher concentration of \( H^+ \) than a substance with a pH of 3.
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which statement about the self-ionization of water is correct? ○ two wa…
B. Two water molecules interact to form a hydronium ion and a hydroxide ion.
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heating curve 1. what is the melting point of the substance? 2. what is…
\( 60^\circ \text{C} \) ### Question 2: What is the boiling point of the substance?
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what is the equilibrium constant of pure water at 25°c? ○ 10¹⁴ ○ 10⁻¹⁴ …
B. \(10^{-14}\)
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consider the reaction below. h₂po₄⁻ + h₂o → h₃o⁺ + hpo₄²⁻ which of the …
A. $\ce{H_{2}O}$ and $\ce{H_{3}O^{+}}$
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which term describes a substance that increases the concentration of hy…
B. Arrhenius definition of a base
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osmium is a chemical element with a density of 22.6 grams per cubic cen…
D. 341.3 grams
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which of the following would most likely act as a bronsted-lowry acid? …
B. HCN
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consider the reaction below. hclo₃ + nh₃ → nh₄⁺ + clo₃⁻ which is a base…
B. $\ce{NH_{3}}$ and $\ce{NH_{4}^{+}}$
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what is the definition of a lewis acid? ○ a substance that accepts elec…
A. a substance that accepts electrons to form a covalent bond
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which statement best describes a bronsted-lowry base? it must accept pr…
B. It must accept protons to form a conjugate acid.
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consider the reaction below. hi + h₂o → h₃o⁺ + i⁻ which is an acid-conj…
D. HI and $\ce{I^-}$
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what is the arrhenius definition of an acid? a substance that increases…
A. A substance that increases $\ce{H_3O^+}$ concentration when it is dissolved in water.
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1) draw an atom of helium, include the electrons, protons and neutrons.…
- Nucleus: 2 protons (labeled p⁺) and 2 neutrons (labeled n⁰). - Electron shell: 2 electrons (labeled e⁻ or "X") in the first shell. ### Question 2: Determine Helium’s oxidation/c…
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what is the bronsted-lowry definition of a base? ○ a compound that dona…
B. a compound that accepts protons
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which reaction displays an example of an arrhenius base? ○ naoh(s) → na…
A. $\ce{NaOH(s) ightarrow Na^{+}(aq) + OH^{-}(aq)}$
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when does phenolphthalein turn pink? ○ in the presence of a base ○ in t…
A. in the presence of a base
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which of these substances contributes to soap’s slippery texture? ○ an …
B. a base
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which pair of substances would most likely result in the production of …
B. soluble metal salt and carbon dioxide
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which of the following best defines an acid? ○ an acid has a ph of 7. ○…
D. An acid has more hydrogen ions in solution.
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oxytocin also plays a role in sexual relationships. the so - called \lo…
A. It encourages us to form emotional bonds with others.
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the reaction below demonstrates which characteristic of a base? $ce{cus…
the ability of a base to react with a soluble metal salt
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h₂co₃ is used in soft drinks. what is the name of this compound? ○ sulf…
B. carbonic acid
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look at the reaction below. h₂so₄(aq) + ca(oh)₂(aq)→caso₄(aq) + 2h₂o(l)…
D. $\ce{Ca(OH)_{2}(aq)}$
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which statement would indicate the presence of an acid? ○ it tastes bit…
C. It reacts with active metals to form a gas.
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13 multiple choice 7 points in chemistry, logarithms are key to calcula…
\( H^+ \approx 2.5 \times 10^{-3} \) (corresponding to the first option: \( H^+ \approx 2.5 \times 10^{-3} \))
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which compound plays an important role in leather processing and electr…
ammonia
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4. how would you write the element symbol for this element? key concept…
1. Atomic number (number of protons) 2. No; neutrons affect mass, not identity (isotopes are same element). 3. No; electrons can vary (ions) without changing the element. 4. No; p…
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multiple-choice (record the best or most correct answer on the student …
To solve these multiple - choice questions, we analyze each one based on the knowledge about Alfred Nobel and nitroglycerin: ### Question 1 Nitroglycerin was first made by Ascanio…
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10 multiple answer 1 point why is methanol cooled before rinsing the cr…
C. Cold methanol prevents dissolution of the purified naphthalene, D. Cold methanol dissolves remaining impurities more effectively
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9 multiple choice 1 point when recrystallizing naphthalene, why is it i…
A. To remove any undissolved impurities
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8 multiple choice 1 point why is methanol handled in a fume hood during…
A. Methanol fumes are toxic and flammable.
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7 multiple choice 1 point after recrystallization, the purified sample …
B. Higher degree of purity
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6 multiple choice 1 point why is methanol initially chosen over water a…
C. Methanol has a lower polarity than water, enhancing naphthalene solubility at high temperatures. (Here we assume the options are labeled A, B, C, D in order. If the original la…
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5 multiple choice 1 point what is the expected solubility behavior of n…
C. Highly soluble in methanol at high temperature but poorly soluble in water at all temperatures
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4 multiple answer 1 point which property of a good recrystallization so…
B. High solubility of the compound at high temperature, D. Low boiling point to evaporate easily, A. Ability to dissolve impurities at all temperatures (Note: Actually, the most e…
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3 multiple choice 1 point what is the main reason for adding water drop…
B. To increase the polarity of the solvent mixture gradually, promoting controlled crystallization.
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2 multiple choice 1 point in mixed-solvent recrystallization, why must …
A. To avoid phase separation and allow uniform solubility adjustment
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pre-lab quiz 3. answer all questions 1 multiple choice 1 point which pa…
B. Hexane - methanol
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name: _______________________________ pd. ____ date: ______________ 5. …
| Symbol | Element Name | Atomic Mass | Atomic Number | Atomic Notation | Number of Protons | Number of Neutrons | Number of Electrons | |--------|--------------|-------------|---…
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which is a way to express concentration of a solution? ○ parts per bill…
A. parts per billion
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given that the molar mass of nano₃ is 85.00 g/mol, what mass of nano₃ i…
255 g
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practice problems 1. compare a molecule of oxygen (o₂) and a molecule o…
B) $CO_2$ ### Problem 3: Fill in the blank: An element is made of only one kind of ______.
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which would be the best way to represent the concentration of a 1.75 m …
B. $\boldsymbol{[K_2CrO_4] = 1.75\ M}$
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a student prepares 150.0 ml of 1.40 m hcl using 35.0 ml of a stock solu…
6.00 M
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1. label the diagram of the atom below using the provided word bank. pr…
1. a. Proton, b. Neutron, c. Electron, d. Electron Shell/Orbit 2. a. Electron, b. Proton, c. Electron Shell/Orbit, d. Neutron 3. a. The number of protons in an atom, b. The sum of…
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which statement best explains the symbol nacl? moles of water per liter…
C. moles of NaCl per liter of solution
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josh prepares a solution by mixing sodium nitrate and water. to calcula…
B. sodium nitrate, because it is the solute
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in a schools laboratory, students require 50.0 ml of 2.50 m h₂so₄ for a…
6.94 mL
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which solution is the most concentrated? ○ 2.0 ml of 10 m h₂so₄, where …
2.0 mL of 10.5 M $\ce{H_2O_2}$, where $\ce{H_2O_2}$ has a molar mass of 34 g/mol
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in a group assignment, students are required to fill 10 beakers with 0.…
200 g (Note: The precise calculation gives approximately 198 g, which is closest to 200 g among the options)
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a student takes a measured volume of 3.00 m hcl to prepare a 50.0 ml sa…
30.0 mL
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the concentration of a solute in a solution is greater than the maximum…
D. supersaturated
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1. t or f - all associates are responsible for working safely and repor…
T ### Question 2
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which factor increases the rate of dissolution in an unsaturated soluti…
A. increasing the temperature
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a 1-l soda bottle contains dissolved carbon dioxide gas. which bottle w…
a bottle that is sealed
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which is true about the dissolving process in water? ○ nonpolar solutes…
C. Molecules or ions of a solute spread throughout the water molecules.
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which is the second step in the dissolving process? ○ the solute is mix…
D. The solvent molecules are attracted to solute particles or ions.
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under which conditions would the solubility of a gas be greatest? ○ hig…
B. high pressure and low temperature
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solute crystals are added to a solution until they begin to sink to the…
D. supersaturated
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under which conditions will sugar most likely dissolve fastest in a cup…
C. sugar crystals with stirring at 15°C
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a chemist has dissolved a certain substance in water. the chemist knows…
unsaturated
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which is true about dissolving a polar substance in water? ○ the solven…
B. The solute particles are carried into the solution.
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which statement best describes a true solution? a true solution will se…
C. A true solution will not separate in a centrifuge.
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which best describes the tyndall effect? ○ the scattering of light by s…
D. the scattering of light by particles in a mixture
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which is a characteristic of a solution? ○ its particles scatter light.…
B. Its particles are evenly distributed.
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mixture a was made by mixing different components together, but it appe…
B. solution
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in which situation can a mixture always be called a solution? when one …
D. when the mixture is homogeneous (assuming the options are labeled A to D as per typical multiple - choice, with the last option being D)
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legal age and limit for blood alcohol content is....... * 4 points ○ 21…
C. 21; .08 (assuming options are labeled A, B, C as first:21;.03, second:21;.09, third:21;.08) ### Second Question (Alcohol effects)
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milk is a heterogeneous mixture that contains different types of partic…
colloid
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which of the following is a homogenous mixture? ○ blood ○ steel ○ cloud…
B. steel
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which solution is a homogeneous mixture? ○ sand and water ○ salt and wa…
B. salt and water
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which is a characteristic of a homogeneous mixture that is a liquid? ○ …
It cannot be separated using filtration.
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review questions: 1. what facility provides care in a patient’s home? 2…
Home health care agency ### Question 2
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there 4,000-7,000 of these chemicals found in this substance. * pills c…
B. Cigarettes ### Second Question:
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read the passage. there are several questions about this passage. from …
4. Synthetic fibers are prone to static charge buildup, and nanoparticle technologies have been developed to help synthetics resist this buildup of static electricity.
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read the passage. there are several questions about this passage. atoms…
4. It uses wordplay to signal a transition from the specific situation of cats to a general explanation of the principles involved in static electricity.
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read the passage. there are several questions about this passage. from …
2. It describes the structure of strands of human hair when they are dry and how the structure changes when hair gets wet.
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read the passage. there are several questions about this passage. from …
2. By incorporating humor, the author keeps readers engaged with a scientific topic that might otherwise seem challenging.
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use the periodic table to answer the question. electronegativity chart …
B. HCl, H₂S, PH₃
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properties unit test what is the ph of a (1 \times 10^{-4}) mol hcl sol…
4
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properties unit test a small amount of sodium hydroxide is added to wat…
The negative log of the concentration of \( \text{OH}^- \) ions is 2. Sodium hydroxide is a strong base.
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properties unit test ammonia is a weak base. potassium hydroxide is a s…
A. A solution of potassium hydroxide will always have more \( \text{OH}^- \) ions than a solution of ammonia.
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question 6 (5 points) listen an atom has 35 protons, 35 neutrons, and 3…
D) 70
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metal reactivity lab - name: name date: ______________ purpose: to obse…
Since no specific question is provided about this Metal Reactivity Lab (e.g., predicting reactions, analyzing results, etc.), it's not possible to give a targeted answer. If you w…
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14b (unit 1) b. perform the following operations. find the calculator a…
### Part b #### i. \( 2.8 \times 10^{-3} \cdot 6.32 \times 10^{-5} \) # Explanation: ## Step1: Multiply coefficients and exponents To multiply numbers in scientific notation, we m…
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how many neutrons are in phosphorus? * 20 16 13 15 how many electrons a…
16 (corresponding to the option "16") ### Second Question: How many electrons are in a neutral element of Calcium?
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how many electrons are in a neutral element of calcium? * 20 19 21 22 w…
A. 20
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how many electrons are in a neutral element of calcium? * 1 point 20 19…
20
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what characteristic do alkaline earth metals share? * they have 1 valen…
39 ### Second Sub - Question: What characteristic do Alkaline Earth Metals share?
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which family contains elements that exist as two gases, one liquid (br)…
Halogens ### Second Question (Which family of elements has exactly one valence electron and is highly reactive with water?):
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what is the atomic number for iron (fe)? ○ 80 ○ 45 ○ 26 ○ 2 how many va…
26 (assuming the option with 26 is one of the choices, likely the third option as per the given choices: 80, 46, 26, 2) ### Second Question: Valence electrons in Group 2 (Alkaline…
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related to... memory (hg) among the...? ○ its the most... ○ its a liqui…
Boron ### Second Question (What is the chemical symbol for Antimony? )
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how many electrons are in a neutral element of calcium? * 20 19 21 22 h…
A. 20 ### Second Question: How many protons are in the element Fluorine?