The lithium-iodine battery is used in pacemakers to generate small electrical impulses that trigger the heart to beat according to the following equation. Identify
the species oxidized.
2 Li(s) + I2 (s) → 2 Lil(aq)
Answer:
The species that oxidizes is lithium, or Li
Explanation:
Since I2 is know to be a halogen, and halogens are oxidizers, iodine is probably not the species being oxidized. So, Li is being oxidized.
Another way to look at the problem is to assign oxidation numbers to all elements on the right and left
The left:
lithium = 0
iodine = 0
Both are 0 since they are in their most stable elemental states
The right:
lithium : +1
Iodine: -1
When something looses an electron and becomes more positive, it is oxidized. Lithium goes from 0 to 1, clearly displaying a rise in oxidization state. So, lithium is being oxidized.
Emilio is describing an ancient law that stated the sun and stars moved around Earth. He states that before Copernicus, everyone believed this law and experimental evidence appeared to support it. Copernicus, however, provided data that showed that Earth orbits the sun.
Which statement describes why Emilio’s description is incorrect?
Emilio reversed the facts.
A law cannot be ancient.
A law cannot be disproved.
Emilio named the incorrect scientist.
The statement that describes why Emilio's description is incorrect is that a law cannot be disproved. Therefore, option C is the correct answer.
Scientific laws are guidelines for how nature will act in specific circumstances, typically expressed as an equation. It can be disproved when a new law emerges. In fact, a law cannot be considered scientific if it cannot be disproved by other's experiments.
For instance, the volume of the gas increases as the gas's temperature rises. We refer to this as a natural law. It was first said that sun and stars revolved around the Earth. But later on, this law was disproved by Copernicus. He stated that Eath revolves around the Sun in its particular orbit.
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What does the author describe in this passage?
The author describes different types of t-shirts.
The author describes reasons for moving to New York City.
The author describes two types of energy.
The author describes the dangers of riding in taxis.
The author describes about two types of energy, in this passage which is motion energy and heat energy.
What are motion energy and heat energy?The energy that results from the movement of atoms and molecules within a substance is known as thermal energy, also known as heat energy. These particles generate more heat as they move more quickly. The thermal energy of the earth is referred to as geothermal energy.
Motion energy is energy that is held in the motion of objects. More energy is stored as they move faster. Energy is required to start an object moving, and energy is released when an object slows down. Motion energy includes things like the wind. A car crash is a dramatic example of motion energy; the vehicle comes to a complete stop and abruptly and uncontrollably releases all of its motion energy.
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What is ph of .530 M solution of carbonic acid that has acid dissociation of 4.4 x 10^-7
Answer
pH = 3.32
Explanation
Given
Acid dissociation of carbonic acid (Ka) = 4.4x10^-7
Concentration = 0.530 M
Solution
The carbonic acid dissociates into:
[tex]\begin{gathered} H_2CO_3\rightarrow\text{ H}^{+\text{ }}+\text{ HCO3}^- \\ \end{gathered}[/tex][tex]\begin{gathered} Ka\text{ = }\frac{[H^+][A^-]}{[HA]} \\ [H^+]\text{ = \lbrack A}^-] \\ Ka\text{ x \lbrack HA\rbrack= \lbrack H}^+]^2 \\ 4.4\text{ x 10}^{-7}\text{ x 0.530 = \lbrack H}^+]^2 \\ 2.332\text{ x 10}^{-7}\text{ = \lbrack H}^+]^2 \\ 4.816\text{ x 10}^{-4}\text{ = \lbrack H}^+] \\ \\ \end{gathered}[/tex]Now we can calculate the pH
pH = -log[H+]
pH = -log[4.816x10^-4]
pH = 3.32
The energy stored in the chemical bonds of a carbohydrate molecule isA. specific heat. B. Kinetic energy. C. potential energy. D. worked.
Answer
C. Potential energy
Explanation
A carbohydrate molecule has chemical bonds, Potential energy is available between chemical bonds.
What is the concentration of a 56.20 mL solution of HBr that is completely titrated by 27.50 mL of a 0.200 M NaOH solution?
The concentration of HBr used in the titration is found to be 0.0978M.
Volume of NaOH used is 27.50ml and it’s molarity used is 0.200M.
Volume of HBr used is 56.20ml.
On comparing molarity of both the solutions, we get the relation
HBr × VHbr = MNaOH × VNaOH
MHBr = 0.200M × 27.50ml /56.20ml
MHBr = 0.0978M.
A colorless, stifling gas called hydrogen bromide is highly dissociated in water and exceedingly soluble in water. In the presence of damp air, it rapidly fumes. Hydrogen bromide gas is a very caustic chemical that, when contacted, can result in serious burns.
To determine the concentration of an identified analyte, titration is a typical laboratory technique for quantitative chemical analysis. A standard solution with a defined concentration and volume is prepared as a reagent, also known as the titrant.
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Starting with the following equation,
Fe₂O₃(s) + Al(s) → Fe(l) + Al₂O₃(s)
calculate the moles of Fe₂O₃ that will be required to produce 645 grams of Fe.
Where do i start and how do I calculate? Need help please
The number of moles of Fe₂O₃ that will be required to produce 645 grams of Fe is 5.78 moles
How to determine the moles of Fe₂O₃ neededWe'll begin by obtainig the number of mole of Fe. This can be obtained as follow:
Mass of Fe = 645 gramsMolar mass of Fe = 55.85 g/molMole of Fe =?Mole = mass / molar
Mole of Fe = 645 / 55.85
Mole of Fe = 11.55 moles
Finally, we shall determine the number of moles of Fe₂O₃ needed. Details below
Fe₂O₃(s) + 2Al(s) → 2Fe(l) + Al₂O₃(s)
From the balanced equation above,
2 moles of Fe were produced from 1 mole of Fe₂O₃
Therefore,
11.55 moles of Fe will be produce from = (11.55 × 1) / 2 = 5.78 moles of Fe₂O₃
Thus, the mole of Fe₂O₃ needed is 5.78 moles
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Determine the empirical formula for each of the following compounds:19% tin and 81% iodine
Answer
The empirical formula for this compound is SnI₄Explanation
Given:
% composition: 19% tin and 81% iodine
What to find:
The empirical formula for the compound
Step-by-step solution:
Assume we have 100 grams total of the substance.
Grams Sn: 19 g
Grams I: 81 g
Now, let's convert the number of grams of each element into moles below:
Moles Sn: 19 g/118.71 g/mol = 0.16 mol
Moles I: 81 g/126.90 g/mol = 0.64 mol
Finally, let's divide the number of moles of each element by the smallest number obtained:
Sn = 0.16/0.16 = 1
I = 0.64/0.16 = 4
Therefore the empirical formula for this compound is SnI₄The 14.7 g sample of graphite takes up a volume of 6.6 cm^3. What is the density of graphite?
The density of graphite that has a volume of 6.6cm³ and a mass of 14.7g is 2.23g/cm³.
How to calculate density?Density is the measure of the mass of matter contained by a unit volume.
The density of a substance can be calculated by dividing the mass of the substance by its volume as follows:
Density = mass ÷ volume
According to this question, graphite has a volume of 6.6cm³ and a mass of 14.7g. The density of this substance can be calculated as follows:
Density = 14.7g ÷ 6.6cm³
Density = 2.23g/cm³
Therefore, 2.23g/cm³ is the density of the graphite.
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Compare the reactivity of the alkali metals family with the reactivity of thehalogen family. (2 points)
The alkali metals grow more reactive as you move down the group, but the halogens become less reactive as you move down, which is one distinction between the reactivity of the groups. The most active halogen is fluorine, whereas the most active naturally occurring alkali metal is cesium.
What are halogens and alkali metals ?
The features of the halogen elements' compounds with other elements and their overall chemical behavior are remarkably similar to one another. However, there is a progressive change in characteristics from fluorine through chlorine, bromine, and iodine to astatine, with fluorine and chlorine having the most marked differences between two succeeding elements. In addition to being the most reactive halogen and element overall, fluorine has a few other characteristics that set it apart from the other halogens.
Lithium (Li), Sodium (Na), Potassium (K), Rubidium (Rb), Cesium (Cs), and Francium are alkali metals, which are elements of group 1. (Fr). Since they only have one electron in their valence shell, they are extremely reactive and strive to adopt the stable octet configuration of the noble gases. The alkali metals exhibit metal properties such as strong thermal and electrical conductivity, lustre, ductility, and malleability. In the outermost shell of each atom of an alkali metal, there is just one electron.
The alkali metals grow more reactive as you move down the group, but the halogens become less reactive as you move down, which is one distinction between the reactivity of the groups. The most active halogen is fluorine, whereas the most active naturally occurring alkali metal is cesium.
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Write the ions present in solution of Pb(C2H3O2)2 .
From the chemical structure of the compound that is clearly shown in the question, the ions that should be in the solution are; lead II ion and the acetate ion.
What are ions?The term ions has to do with the species that have a positive charge or a negative charge. Thus we could define an ion as as a charged specie. The charge could owe to an excess of electrons in which case the charge is negative or due to a deficiency of electrons which gives us a positive charge.
Looking at the compound that is in solution, we can see that the ions that are present are lead II ion and the acetate ion.
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How does the availability of WATER affect the growth of plants and animals?
Answer:
all living things need water. no water, no life.
(4.3) Congratulations, you've been hired by the Chemistry Department to prepare the chemicals
for G-Chem Lab. This week, 4.2 L of a 0.74 M HCl solution is needed. When you go to the
stockroom, you can only find a 4 L bottle of concentrated HCI solution which is 37% by mass HCI
and has a density of 1.1786 g/mL.
a. Calculate the molarity of HCI in the concentrated HCI solution. (Hint: Assume 1 L of
solution.)
b.
Calculate the volume (in mL) of the concentrated solution you'll need to dilute to prepare
the required solution for this week's lab.
Morality is the body of rules that enables individuals to coexist peacefully in groups. In order to act morally, people may have to sacrifice their own immediate interests in order to further society. It is what societies deem to be "acceptable" and "proper.
Explain molarity of HCI in the concentrated HCI solution?The standard by which society determines whether behaviour is appropriate and inappropriate is morality. Morality is demonstrated by the conviction that it is immoral to take something that is not theirs, even if no one would notice.
Hydrochloric acid is a colourless solution of hydrogen chloride (HCl) in water. Concentrated HCl is a particularly corrosive acid with several industrial uses. The pH levels of swimming pools are changed using this material, which is usually referred to as "muriatic acid" in this context, to make them safe to use and to disinfect the water.
Molarity is defined in terms of the volume of the solution, NOT the volume of water. Inaccurate = 5.0 The solution is humour.
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Is there any limit to the distance through which diffusion can occur?
Answer
Yes, there is a limit to the distance through which diffusion can occur. This is because diffusion time increases with the square of diffusion distance. Diffusion time is inversely proportional to the diffusion coefficient. hus, if the diffusion distance is small, diffusion happens faster because the particles do not have as far to travel.
Neon has three stable nautrally occurring isotopes. The isotopic mass and percent abundance of these isotopes are given inthe table.Isotope20 Ne21 Ne22 NeIsotopic mass (u)19.9920.9921.99Abundance (%)90.480.2279.25Calculate the average atomic mass of neon.
To calculate the average mass of Ne (neon), we have to use this formula:
[tex]\text{Average atomic mass = }\frac{\sum ^{}_{}(\text{mass of isotopes)x(abundance \%)}}{100}[/tex][tex]\begin{gathered} \text{Average atomic mass = }\frac{(19.99ux90.48+20.99ux0.27\text{ +}21.99ux9.25)}{100} \\ \text{Average atomic mass = }20.18\text{ u} \end{gathered}[/tex]The average atomic mass of Ne = 20.18 u
When do an ice cube and warm soda reach thermal equilibrium?
Convert 62.00nm/s to pm/ms
62.00 nanometres per second is equivalent to 62 picometre per milliseconds
How to convert picometers to nanometres?Picometers is a SI unit of length equal to 10−¹² meters with a symbol pm while nanometres is another SI subunit of length equal to 10-⁹ metres with symbol nm.
The conversion factor of picometers and nanometres is as follows:
1 picometre = 0.001 nanometre
This means that 62 nanometre will be equal to 62000 picometres.
1 second = 1000 milliseconds
62000/1000 = 62 pm/ms.
Therefore, it can be said that 62.00nm/s is the same as 62 pm/ms based on the conversion factor above.
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Can you label the important processes in the water cycle?
The important processes of the water cycle are:
evaporation,condensation, andprecipitationWhat is the water cycle?The water cycle refers to the processes by which water is replenished or renewed in the environment.
There are three processes in the water cycle, and they are:
evaporation - this is the process by which water molecules in liquid form are converted to water vapor.condensation - this is the process by which water vapor molecules in the atmosphere come together to form clouds.precipitation- this is the process by which the water molecules in the cloud precipitate as either rain, snow, or ice.Learn more about the water cycle at: https://brainly.com/question/28396050
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A radio station emits radiation at à wavelength of 3.10m. What is the station’s frequency in megahertz?
Answer: 96.7072445
Explanation: F = 1/T
Why is KMnO4 regarded as a secondary standard solution ?
Potassium permanganate is not used as primary standard because is not able to release in MnO2 in the reaction. According to the above discussion, we conclude KMnO4 is used as the secondary standard. It is also hygroscopic in nature.
What is Secondary Standard solution?
A solution created especially for a certain analysis is known as a secondary standard solution. A substance whose active agent contents have been identified by comparison with a primary standard is referred to as a secondary standard. This indicates that it is frequently standardized against a fundamental standard.
Analytical tools and methodologies are calibrated using secondary standard solutions.
The molecular formula of potassium permanganate is KMnO4. Potassium permanganate is one of the oxidising agents in chemistry. Potassium permanganate is not used as primary standard because is not able to release in MnO2 in the reaction. Potassium permanganate is always in the stable form. The reason KMnO4 is also used as a colour indicator in analysis.
According to the above discussion, we conclude KMnO4 is used as the secondary standard. It is also hygroscopic in nature.
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1. For the reaction CO(g) + NO₂(g) → CO₂(g) + NO(g), a CO₂ concentration of 0.040
moles/liter was measures at 2 seconds. What was the average reaction rate
for this reaction? (Please note that at t = 0, no CO₂ was present.)
Average reaction rate is 0.02 mol/liter/sec
What is an average reaction rate?Change in concentration divided by the change in time gives average reaction rate. The rate of a chemical reaction is measured in mol/l/s.
Average rate is defined as the change in molar concentration of either reactants or products in time is called as average rate. The concentration of reactants decreases during reaction, whereas the concentration of products keeps on increasing until an equilibrium is reached.
Evaluating an average rate shows the amount of change of one variable with respect to another. The other variable is generally time that describes the average change in distance or chemical concentrations.
For the given reaction
CO(g) + NO₂(g) → CO₂(g) + NO(g), a CO₂
concentration of 0.040
moles/liter was measured at 2 seconds.
Average reaction rate = concentration/ time
0.040/ 2
=0.02 mol/l/sec
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Water, table salt, and tin metal are all pure substances. Which of these pure substances are compounds
Answer:
water and salt are compounds, water is H2O and table salt is NaCl.
tin is just a metal, an element, not a compound.
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How many grams of KClO3 are needed to produce 6.75 Liters of O2 gas measured at 1.3 atm pressure and 298 K?
Answer
29.3171 g KClO₃
Procedure
To solve this question consider the following chemical reaction:
2KClO₃→2KCl+3O₂
Then we will use the ideal gas formula to determine the number of moles present in 6.75 L of oxygen gas.
Data:
V=6.75 L
T= 298 °K
P= 1.3 atm
R= 0.08206 L⋅atm⋅°K⁻¹⋅mol⁻¹
Equation
PV=nRT
Solve for n to get the moles
[tex]n=\frac{PV}{RT}=\frac{1.3\text{ atm }6.75\text{ L mol }\degree\text{K}}{0.08206\text{ L.atm 298}\degree\text{K}}=0.3588\text{ mol O}_2[/tex]Use the stoichiometry of the reaction to convert from moles of oxygen to moles of KClO₃.
[tex]0.3588\text{ mol O}_2\frac{2\text{ mol KClO}_3}{3\text{ mol O}_2}=0.2392\text{ mol KClO}_3[/tex]Finally, convert from moles to grams
[tex]0.2392\text{ mol KClO}_3\frac{122.55\text{ g KClO}_3\text{ }}{1\text{ mol KClO}_3}=\text{ 29.3171 g KClO}_3[/tex]what is the concentration mass divided by volume percent of a solution prepared from 50 g in HCl and 2.5 L of water
The concentration mass by volume percent of a solution is 2 %
What is mass by volume percent of a solution ?
The ratio of the mass of the solute present in a solution to the volume of the solution as a whole is known as the mass/volume percent. The given proportion must be multiplied by 100 because this type of concentration is expressed as a percentage, as shown below.
Mass/Volume Percent is calculated as follows:
mass (solute(g)) / Volume(solution(mL) x 100
Given that:-
Mass of solute =50g
Volume of solution =2.5L = 2500mL
As we know that, mass by volume percentage of the solution is given by-
Mass by volume %= mass of solute/Volume of solution *100
= 50/2500*100 = 2 %
The concentration mass by volume percent of a solution is 2 %
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What is the total moles of particles in 3.0 L of each of the following solutionhalf-normal NaCl , 0.40 % (m/v) , used to provide electrolytesExpress your answer using two significant figures.
The given concentration, 0.40% (m/v), is a mass volume percent concentration. It indicates us that there are 0.40g of NaCl in every 100mL of solution.
We can use this information to detemine how many grams of NaCl are there in 3.0L (3000mL) of solution:
[tex]3000mL\cdot\frac{0.40g}{100mL}=12g[/tex]Now, convert this amount of mass to moles using NaCl molar mass:
[tex]12gNaCl\cdot\frac{1molNaCl}{58.44gNaCl}=0.20molNaCl[/tex]It means that the corect answer is 0.20 moles of NaCl.
Calculate % concentration of of solution prepared by dissolving 8.5 g of glucose (C6H1206) in 35 g of water24 %none of the other answers are correct1.35 %20.%4.1 %
- First, to calculate the % concentration of glucose in the solution, we need to add the 8.5g of glucose to the 35 g of water, to get the weight of the solution:
[tex]\begin{gathered} \text{solution weight=8.5g + 35g} \\ \text{solution weight=43.5g} \end{gathered}[/tex]- Second, we calculate the %w/w (weight/weight) with the solute weight and the solution weight:
[tex]undefined[/tex]- So,
Cells can regulate different processes in two ways. They can turn on and off the genes that make enzymes, or they can Question 16 options: A) decrease the amount of energy needed to carry out the preferred process. B) increase the activation energy of a reaction. C) regulate the enzymes that are already made. D) increase the amount of energy needed to carry out the preferred process.
In the process of metabolic regulation, cells can turn on and off the genes that make enzymes, or they can regulate the enzymes that are already made; option C.
What is the mechanism of regulation of metabolic processes that cells employ?Metabolic processes are the processes by which the cell carries out its activities.
There are types of metabolic activities that occur in the cells:
catabolism, and anabolismCatabolism is the metabolic process in cells by which large molecules are broken down to release energy required by the body to carry out other cellular actities. An example of catabolism is glycolysis.
Anabolism - this is a metabolic process in cells where energy is used to produce large molecules from the small molecules present in the cells. An example of catabolism is protein synthesis from amino acids.
The cells need to regulate these two processes and this is known as metabolic regulation.
The cells regulate these processes at the gene level that produces the enzyme that catalyzes these processes or by regulating the activity of the enzymes.
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Please help with this
Answer:
its the 3rd one
Explanation:
- For one of the valence electrons in the Helium atom, do you think the pull on that electron would be greater than,
less than, or equal to the pull on the Hydrogen atom's valence electron? Use Coulomb's law to support your
answer.
The Hydrogen atom's valence electron Fluorine attracts electrons better than any other element.
The more electronegative atom pulls the bond electrons harder so the shared electrons spend more than half of the time on the more electronegative atom, giving it a partial negative charge. For example, in water O is more electronegative than H and thus has a partial negative charge.
The higher the ionization energy the stronger the attraction between the nucleus and the valence electrons requiring more energy to remove the valences. electronic. The further away the electron is from the nucleus the more likely it is to be ejected. In other words, ionization energy is a function of atomic radius. The larger the radius the smaller the amount of energy required to remove an electron from the outermost orbital.
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How many grams of hydrofluoric acid are formed when 173.63 grams of hydrogen (H2) react with 173.63 grams of fluorine (F2):
H2 + F2 rightwards arrow 2HF
The amount, in grams, of hydrofluoric acid that will be formed when 173.63 grams of hydrogen reacts with 173,63 grams of fluorine would be 182.8 grams.
Stoichiometric problemThe balanced equation of the reaction is written as:
[tex]H_2 + F_2 -- > 2HF[/tex]
According to the equation, the mole ratio of hydrogen and fluorine that react to produce hydrofluoric acid is 1:1.
Recall that: mole of substance = mass of the substance/molar mass
Molar mass of [tex]H_2[/tex] = 1x2 = 2 g/mol
Molar mass of [tex]F_2[/tex] = 19x2 = 38 g/mol
Mole of 173.63 grams [tex]H_2[/tex] = 173.63/2
= 86.82 moles
Mole of 173.63 grams [tex]F_2[/tex] = 173.63/38
= 4.57 moles.
Considering the mole ratio of the two reactants, it appears that fluorine is limited in availability and will, therefore, determine the amount of hydrofluoric acid that will be produced.
Mole ratio of fluorine to hydrofluoric acid = 1:2.
Equivalent mole of hydrofluoric acid = 4.57 x 2 = 9.14 moles.
Mass of 9.14 moles HF = 9.14 x 20
= 182.8 grams
Thus, the amount of hydrofluoric acid formed from the reaction is 182.8 grams.
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