. From left to right across a period in the periodic table, elements become less ___________ and more ______________ in their properties. 26. Francium has 36 isotopes, but only francium-223 occurs in nature. Francium-223 spontaneously emits particles and energy, so francium-223 is a(an) _____________ of francium. 27. At sea level, water ______________ at 100°C. 28. Cooking requires continuous addition of energy to the chemical reactions that are taking place. The chemical reactions involved in cooking can be described as __________________.
25. From left to right across a period in the periodic table, elements become less ___metalic________ and more _____nonmetalic _________ in their properties.
26. Francium has 36 isotopes, but only francium-223 occurs in nature. Francium-223 spontaneously emits particles and energy, so francium-223 is a(an) ______radioctiveistoop_______ of francium.
27. At sea level, water boils at 100°C.
28. Cooking requires continuous addition of energy to the chemical reactions that are taking place. The chemical reactions involved in cooking can be described as ______endothgermic____________.
29. The _______kinetic energy_________ theory of matter states that all particles of matter are in constant motion.
30. In Rutherford’s experiments, some of the _alpha particles____aimed at gold atoms bounced back, suggesting that a solid mass was at the center of the atom.
31. You are given the melting points of three unknown substances and are asked to predict which one is an ionic compound. You would select the compound with the ________highest________ melting point.
which of the following is an electric charge?
a. north
b. south
c. neutral
d. unassigned
Which of the following values is equal to 1 micrometer?
A.) 0.000001 meter
B.) 0.001 meter
C.) 1,000 meter
D.) 1,000,000 meter
Answer : Option A) 0.000001 meter
Explanation : The value which will be equal to 1 micrometer will be 0.000001 meter.
As the conversion factor for 1 μm = [tex] 1 X 10^{-6} [/tex] m
So while converting micrometer to meter will be by converting micrometer to meter [tex] 1 X 10^{-6} [/tex] m in decimal it will be 0.000001 meter.
0.000001 meter is the measurement that equates to 1 micrometer. Hence option A is correct.
What is calibration in measurement?The process of calibrating a device involves comparing its measurement values to those of a calibration standard with known accuracy. A good example is one in the given option 0.000001 meter
Since accurate measurements are essential to the quality, safety, and innovation of the majority of the goods and services we use and rely on every day, calibration is crucial to ensure accurate measurements.
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What is the hydroxide concentration of a solution with a pH of 12.80?
Answer:
6.31 × 10^-2M
Explanation:
pH +pOH=14
14-12.80=1.20
10^-1.2=.0631
move the decimal two places to the right
=6.31 × 10^-2
Multiply the following numbers and write the answer in scientific notation: (3.45 × 107) × (6.25 × 105).
what is scientific theory?
A theory that explains scientific observation.
scientific theories must be falsifiable
Which element is most likely to bend without breaking?
Answer:
cobalt (Co) is the correct answer.
Explanation:
The is most likely to bend without breaking element is cobalt because of the following properties.
Cobalt is a ferromagnetic metal.Cobalt is a brittle and hard element.cobalt is not a nonmetal, it is a metal and metals are malleable and ductile means they can bend without breaking.Hence Cobalt in their solid form they can be easily bent and changed into thin films without breaking
Mr. Adams asked his students to write the chemical symbols for the element zinc. He wrote the student's answers on the whiteboard. Which answer is correct?
Answer:
The chemical symbol of zinc element is Zn.
Explanation:
The chemical symbol of zinc element is 'Zn'.
Zinc is a metal belonging 3-d transition series metal with atomic number 30 and atomic mass of 65.38 g/mol. It has blue silvery appearances.
The electronic configuration of Zinc:
[tex\]Zn=[Ar]3d^{10}4s^2[/tex]
What is the mass of exactly 1 mol of the following elements osmium, Cesium, krypton
Answer: The mass of osmium is 190.23 g/mol, cesium is 132.9 g/mol and that of krypton is 83.8 g/mol
Explanation:
Molar mass is defined as the mass of 1 mole of an element. It is expressed in g/mol.
For the given elements:
Osmium is 76th element of the periodic table having mass of 190.23 u
Molar mass of osmium = 190.23 g/mol
Cesium is 55th element of the periodic table having mass of 132.9 u
Molar mass of cesium = 132.9 g/mol
Krypton is 36th element of the periodic table having mass of 83.8 u
Molar mass of krypton = 83.8 g/mol
Hence, the mass of osmium is 190.23 g/mol, cesium is 132.9 g/mol and that of krypton is 83.8 g/mol
For the quantum number lower case L = 0, how many possible values are there for the quantum number m subscrip l?
A sample of fluorine gas exerts a pressure of 900 mmHg. When the pressure is changed to 1140 mmHg, the volume is 250 mL. What was the original volume?
silver tarnishes when it comes into contact with hydrogen sulfide in the air.
physical property or chemical property
Final answer:
Silver tarnishing is a chemical property, as it involves a reaction between silver and hydrogen sulfide in the air to form silver sulfide. This process alters the composition of the silver, differentiating it from physical properties.
Explanation:
The tarnishing of silver is a result of a chemical reaction between silver and hydrogen sulfide in the air. When silver tarnishes, it essentially reacts with hydrogen sulfide gas to form a compound called silver sulfide, which has a dark, streaky black appearance. The chemical equation for this reaction is 2 Ag(s) + H₂S(g) → Ag₂S(s) + H₂(g). This tarnish is not simply a surface dirt or residue that can be washed off, but a fundamental change in the surface layer of the silver object itself, which is why tarnishing is considered a chemical property.
The formation of silver sulfide (tarnish) indicates a change in the composition of the silver item, which differentiates this chemical property from physical properties that do not involve a change in chemical composition. Physical properties can include melting point, density, or color in a physical state, whereas chemical properties involve the substance's ability to undergo a specific chemical change. In this context, the tarnishing of silver aligns with other chemical properties such as the ability of iron to rust or for substances to burn, rot, explode, decompose, or ferment.
what is the systematic study of the natural world
Chemical energy in burning wood is changed into thermal energy. The thermal energy is absorbed by water, which boils to produce steam. The thermal energy is changed into kinetic energy in the moving steam. The kinetic energy is used to turn a turbine, which converts the kinetic energy into electricity. Which sentence best describes this system?
Answer:
C. It involves both energy transformation and energy transfer.
A scientist carries out an experiment how could she help other scientists judge the validity
of her results
The correct answer is B) let other scientists closely review her work.
A scientist carries out an experiment. She could help other scientists judge the validity of her results by letting other scientists closely review her work.
The scientist that has a discovery can have validation of its exériment if it allows other scientists to review its procedures, the methods, the results, and the way the scientists applied the scientific method during its research. This way the scientist can confirm that its work was good, valid, and can publish its conclusions in a scientific journal.
The other options of the question were A) use confusing language in her report, C) prevent others from seeing her data, and D) keep her experimental procedure a secret.
How does the amount of salt dissolve in water affect the density of water
Answer: How the amount of salt dissolve in water affect the density of water is the density of the water increases because the mass of the water increases.
Explanation:
What mass of iron is required to replace over from 8.00 g of silver nitrate dissolved in water
a substance has a volume of 20mL and a density of 2.5 g/mL. what is it’s mass?
0.125 g
8 g
22.5 g
50 g
A substance has a volume of 20mL and a density of 2.5 g/mL. 50 grams is its mass. Option D is correct.
What is density?The density of a substance is the amount of substance present in pe unit volume in cubic centimeters in the area and it is the ratio of mass and the volume of the substance unit is a centimeter cube.
The volume of a substance is 20mL and the density of the substance 2.5 g/mL so, the mass will be
Density = mass/ volume
Substituting the value, Mass = density × Volume
Mass = 2.5 × 20
Mass = 50 grams.
Therefore, Option D is correct. A substance has a volume of 20mL and a density of 2.5 g/mL. 50 grams is its mass.
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Which refers to the amount of a solute that will dissolve in a given volume of solvent at a given temperature and pressure
Answer:
The correct answer is solubility.
Explanation:
Solubility is illustrated as the maximum concentration of solute, which can be dissolved in a given amount of solvent at a specific pressure and temperature. Each solute exhibits a specific solubility. The solubility is generally articulated in the form of solute per 100 ml or grams or solvent, at a specific temperature and pressure.
Select all of the answers that apply.
Which of the following are sources of biomass?
wood
the Sun
manure
water
paper
trash
food crops
The biomass is the plant or animal product or waste which is not used for eating or feeding and is used for generation of energy (in form of heat or other forms). so biomass if source of energy obtained from biological products.
In the given options
Wood : its waste can be used as biomass
Sun : it is the source of solar energy
Manure: it is decomposed product biological material used in agriculture
Water: it is not a source of energy directly
paper : it is also a product of wood but is not considered to be biomass
trash : it depends that what is present in trash and how it can be used
food crops: yes these are biomass
Answer:
I believe wood and food crops are the correct answers.
2.22 moles of HCl are dissolved in enough water to make 1.5 liters of solution.
Show work.
A. 1.0 M
B. 1.25 M
C. 1.5 M
D. 2.0 M
E. 2.5 M
To find the molarity of the HCl solution, divide the number of moles of HCl (2.22) by the volume of the solution (1.5 L), which results in a molarity of 1.48 M. This is rounded to 1.5 M to match the closest given answer option.
The question is asking you to calculate the molarity of the HCl solution when 2.22 moles of HCl are dissolved in 1.5 liters of water. Molarity (M) is defined as the number of moles of solute (in this case HCl) divided by the volume of the solution in liters. To calculate the molarity, follow these steps:
Write down the known values: moles of HCl (moles) = 2.22 moles, volume of solution (V) = 1.5 L.
Use the molarity formula: M = moles/V.
Calculate molarity: M = 2.22 moles / 1.5 L = 1.48 M.
Since molarity has to be reported to correct significant figures, and given options do not include 1.48 M, we round to the closest given option, which is 1.5 M (C).
What is the ∆G for the following reaction under standard conditions (T = 298 K) for the formation of NH4NO3(s)? 2NH3(g) + 2O2(g) NH4NO3(s) + H2O(l) Given: NH4NO3(s): ∆Hf = -365.56 kJ ∆Sf = 151.08 J/K. NH3(g): ∆Hf = -46.11 kJ ∆Sf = 192.45 J/K. H2O(l): ∆Hf = -285.830 kJ ∆Sf = 69.91 J/K. O2(g): ∆Hf = 0.00 kJ ∆Sf = 205 J/K. 186.6 kJ 6.9 kJ -10.4 kJ -126.3 kJ -382 kJ
Answer: The [tex]\Delta G[/tex] for the reaction is -382 kJ.
Explanation:
For the following reaction:
[tex]2NH_3(g)+2O_2(g)\rightarrow NH_4NO_3(s)+H_2O(l)[/tex]
Equation used to calculate [tex]\Delta H_{rxn}[/tex] is:[tex]\Delta H_{rxn}=\sum \Delta H_{products}-\sum \Delta H_{reactants}[/tex]
We are given:
[tex]\Delta H_{NH_3}=-46.11kJ/mol\\\Delta H_{O_2}=0.00kJ/mol\\\Delta H_{NH_4NO_3}=-365.56kJ/mol\\\Delta H_{H_2O}=-285.830kJ/mol[/tex]
[tex]\Delta H_{rxn}[/tex] for the reaction is calculated by:
[tex]\Delta H_{rxn}=[1(\Delta H_{NH_4NO_3})+1(\Delta H_{H_2O})]-[2(\Delta H_{NH_3})+2(\Delta H_{O_2})][/tex]
Putting values in above equation, we get:
[tex]\Delta H_{rxn}=[1(-365.56)+1(-285.83)]-[2(-46.11)+2(0)]kJ\\\\\Delta H_{rxn}=-559.17kJ=559170J[/tex]
Equation used to calculate [tex]\Delta S_{rxn}[/tex] is:[tex]\Delta S_{rxn}=\sum \Delta S_{products}-\sum \Delta S_{reactants}[/tex]
We are given:
[tex]\Delta S_{NH_3}=192.45J/K\\\Delta S_{O_2}=205J/K\\\Delta S_{NH_4NO_3}=151.08J/K\\\Delta S_{H_2O}=69.91J/K[/tex]
[tex]\Delta S_{rxn}[/tex] for the reaction is calculated by:
[tex]\Delta S_{rxn}=[1(\Delta S_{NH_4NO_3})+1(\Delta S_{H_2O})]-[2(\Delta S_{NH_3})+2(\Delta S_{O_2})][/tex]
Putting values in above equation, we get:
[tex]\Delta S_{rxn}=[1(151.08)+1(69.91)]-[2(192.45)+2(205)]J/K\\\\\Delta S_{rxn}=-573.91J/K[/tex]
Now, to calculate [tex]\Delta G[/tex], the equation used is:[tex]\Delta G=\Delta H-T\Delta S[/tex]
We are given:
[tex]\Delta H=-559170J\\T=298K\\\Delta S=-573.91J/K\\[/tex]
Putting values in above equation, we get:
[tex]\Delta G=(-559170J)-[298K\times (-573.91J/K)]\\\\\Delta G=-382kJ[/tex]
Hence, the [tex]\Delta G[/tex] for the reaction is -382 kJ.
which of the following must be cleaned and sanitized
Critical items must be sterile, semicritical items require a high level of disinfection, and noncritical items need to be clean but not highly disinfected.
The items that must be cleaning and sanitizing items include:
Critical items: These are items that will be used inside the body, such as surgical instruments, catheters, and intravenous fluids. They must be sterile.
Semicritical items: Examples of these items include gastrointestinal endoscopes and equipment for respiratory therapies.
They may contact mucous membranes or nonintact skin but do not penetrate tissues.
Semicritical items do not typically need to be sterilized but do require a high level of disinfection.
Noncritical items: These are items that may only contact intact skin. Examples include bed linens, furniture, crutches, stethoscopes, and blood pressure cuffs.
These items need to be clean but not highly disinfected.
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In Part A, we saw that the theoretical yield of aluminum oxide is 0.800 mol . Calculate the percent yield if the actual yield of aluminum oxide is 0.456 mol .
Answer:
The percent yield is 58.12 %.
Explanation:
Theoretical yield of aluminum oxide = 0.800 mol
Theoretical amount of aluminum oxide = 0.800 mol × 102 g/mol = 81.6 g
Actual or experimental yield of aluminum oxide = 0.465 mol
Experimental amount of aluminum oxide = 0.465 mol × 102 g/mol = 47.43 g
[tex]\% yield=frac{\text{Experimental yield}}{\text{Actual yield}}\times 100[/tex]
[tex]\%=\frac{47.43 g}{81.6 g}\times 100=58.12\%[/tex]
The percent yield is 58.12 %.
Which of the following measurements is equal to 150 dL?
A) .015 daL
B) 0.15 L
C) 1,500 cL
D) 150,000 mL
Final answer:
The correct answers are C) 1,500 centiliters (cL) and D) 150,000 milliliters (mL) because both equal 150 deciliters (dL) after conversion.
Explanation:
The student's question asks which of the following measurements is equal to 150 deciliters (dL): A) .015 dekaliters (daL), B) 0.15 liters (L), C) 1,500 centiliters (cL), or D) 150,000 milliliters (mL). Converting these options to deciliters will help us find the correct answer:
Option A: 0.015 daL is equal to 1.5 dL (because 1 daL = 10 dL).Option B: 0.15 L is equal to 15 dL (because 1 L = 10 dL).Option C: 1,500 cL is equal to 150 dL (because 1 cL = 0.1 dL).Option D: 150,000 mL is equal to 150 dL (because 1,000 mL = 1 L and 1 L = 10 dL).So, both options C and D are correct. They both equal 150 dL when converted.
Is this equation balanced and in the lowest form? 4NH3 → 2N2 + 6H2 Yes, because there are equal amounts of atoms of each element on both sides. No, because the coefficients could be reduced to 2,1, and 3. Yes, because the coefficients are in their lowest whole number ratio. No, because the coefficients could be reduced to 2, 2, and 4.
Answer: The given equation is not balanced in its lowest form because the coefficients could be reduced to 2, 1 and 3.
Explanation: We are given a equation but it is not balanced in its lowest form, so to reduce it into its lowest form, we divide the whole equation by 2.
The equation becomes:
[tex]2NH_3\rightarrow N_2+3H_2[/tex]
The coefficients for the equation are 2, 1 and 3.
what is the difference between cytokinesis and mitosis
Mitosis and cytokinesis are two processes in the cell division cycle. Mitosis refers to the division of the cell nucleus and occurs before cytokinesis. Cytokinesis is the final step that divides the cell into two separate daughter cells.
Explanation:Mitosis and cytokinesis are two crucial processes in the cell division cycle. Mitosis refers to the division of the nucleus, where the contents of the nucleus get divided equitably and distributed between its two halves. This process is divided into four major stages: prophase, metaphase, anaphase, and telophase.
Cytokinesis, however, occurs after mitosis and is the process that divides the cell's cytoplasm and body into two separate cells, becoming the final step in the cell division process. In animal cells, this usually begins during the late anaphase and involves a contractile ring composed of actin filaments. For plant cells, which have cell walls, the process is a bit different.
So basically, mitosis is the process by which the cell nucleus divides, whereas cytokinesis is the process that completes cell division by splitting the cell itself into two new cells.
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What was the major weakness of Wegener's theory of continental drift
Alfred Wegener proposed the continental drift theory in four reasons. One, he hypothesized that the continents were once a giant continent. Two, he observed that there are fossils found of the same kind in the different locations. Three, he found that the edge of opposing continents somehow fits if they are combined, almost like a puzzle. And four, there are glacial scars that are left behind by a larger glacial continent. His greatest weakness of Alfred Wegeners’ continental drift theory was he could not explain what kind of force that caused this continents to move far from each other.
Liquids and solids are referred to as “condensed phases” because the attractive forces are?
Explanation:
Condensed phase means that there is less space between the molecules of a matter. And a condensed phase do not compress easily so basically, they resist compression.
For example, solids and liquids are both condensed phases as there is less space between their particles and hence they are closer as compared to particles of a gaseous phase.
Though they have fixed volume but both of them are resistant to compression.
Therefore, we can conclude that liquids and solids are referred to as “condensed phases” because the attractive forces leave little space between the molecules.
What conclusion can be made from Ernest Rutherford's the gold foil experiment