Answer: Iridium
Explanation:
The atomic number of Iridium is 77.
The element we obtain if we remove two protons and two neutrons from the gold is iridium. The atomic number of gold is 79 and that of iridium is 77.
What is iridium?Iridium is the 77th element in the periodic table. It is a transition metal like gold, silver, platinum etc. Iridium is a d-block metal and have its valence electrons in d-orbital.
Gold is 79th element and it is also a transition metal. Gold is a precious metal used in making ornaments and its having high cost.
The atomic number of gold is 79 and it have 79 electrons and 79 protons. The atomic number of an element is the number of its protons and the mass number of the element is the sum of number of electrons and number of protons.
If we remove two protons from the 79 protons of gold the proton number becomes 77 and thus the atomic number. The elements with the atomic number 77 is iridium.
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A pure liquid has a constant boiling point, but a liquid with a constant boiling point is not necessarily pure. Explain.
A pure liquid has a constant boiling point (at constant pressure). A change in boiling during distillation is an indication of impurity. The opposite, proposition, however, is not always true, and a constant boiling point does not necessarily mean that the liquid is pure.
This is because, at the boiling point, vapor and liquid are in equilibrium, and, if the composition of the vapor and liquid remains constant through the process, the temperature will also remain constant.
The boiling point can differ by location depending on pressure. Why does not a pure liquid in a distilling flask vaporize all at once whilst the boiling temperature is reached? Additional heat must be supplied for a phase change to occur.
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How many chlorine molecules are in 6.5 moles of chlorine?
Answer:
the number of chlorine molecules in 6.5 moles of chlorine is calculated as follows
by use of Avogadro constant that is 1mole = 6.02 x10^23 molecules
what about 6.5 moles
6.5 x ( 6.02x 10^23)= 3.913 x10^24
Which best describes the reducing agent in the reaction below? cl2(aq) 2br–(aq) right arrow. 2cl–(aq) br2(aq)
The [tex]Br^{-}[/tex] describes the reducing agent in the reaction below.
[tex]Cl_{2} (aq) + 2Br^{-} (aq)[/tex] → [tex]2Cl^{-}(aq) + Br_{2}( aq)[/tex]
Reducing agent is the species in which oxidation is takes place. Reducing agent is the species in which loss of electrons is takes place. In the above reaction bromine ion in left hand side of the reaction loss electron to become bromine atom. So, bromine ion is reducing agent.
Oxidizing agent is the species in which reduction is takes place. Oxidizing agent is the species in which gain of electrons is takes place. In the above reaction chlorine atom in right hand side of the reaction gain electron to become chlorine ion. So, chlorine atom is reducing agent.
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Which of the following atoms would be an ion?
A. An atom with 11 protons and 9 electrons.
B. An atom with 5 protons and 5 electrons.
C. None of these
D. An atom with 8 protons and 8 neutrons.
Considering the definition of ion, an atom with 11 protons and 9 electrons (option A) is an ion since the number of electrons is less than the number of protons, acquiring a positive charge.
What is an ionAn ion is an electrically charged particle that is made up of an atom or molecule that is not electrically neutral, that is, that in its constitution has gained or lost electrons.
In other words, an ion is a molecule or atom that has a positive or negative electrical charge. That is, an ion is an atom whose electrical charge is not neutral.
On the other hand, an atom is made up of a nucleus made up of protons (positively charged) and neutrons (neutrally charged), around which electrons (negatively charged) orbit.
An atom has as many protons as electrons, so the total charge is zero and it is globally neutral.
The loss or gain of electrons allows the atom to acquire an electrical charge, transforming itself into an ion. If the electrical charge is positive, it is called a cation; if it is negative, it is called an anion.
SummaryAn atom with 11 protons and 9 electrons (option A) is an ion since the number of electrons is less than the number of protons, acquiring a positive charge.
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TRY
Which element, represented by X, reacts with chlorine to produce the compound XCI?
Answer:
Aluminum
Explanation:
Each chlorine atom needs one more valence electron to have a full valence electron shell, so X needs to have 3 valuence electrons. The only that satisfies this is aluminum.
(REALLLY NEED HELP) What takes extra electrical current from a wire or appliance and prevents it from going somewhere dangerous?
a ground
a resistor
a loopback
a current
Answer:
A resistor resists extra electric current.
Explain why increasing extracellular k reduces the net diffusion of k out of the neuron through the k leak channels
This because the concentration gradient does not favor diffusion of potassium ions through the K leak channels.
What is diffusion?Diffusion is the movement of molecules of substances from regions of high concentration to regions of low concentration.
Diffusion of ions through the cell membrane takes places through leak channels due to concentration gradient.
The diffusion of potassium ions in and out of the cell depends on the extracellular concentration of potassium ions.
When extracellular concentration of potassium ions increases, it reduces the net diffusion of K out of the neuron through the k leak channels because the concentration gradient does not favor outward movement of potassium ions.
In conclusion, the diffusion of potassium ions through K leak channels depends on concentration gradient.
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A solution with a pH = 13 has approximately how many moles of OH– ions per liter?
Answer:
1 × 10-¹ moldm-³
Explanation:
Pkw = PH + POH
14 = 13 + POH
POH = 1
so , [OH-] = 1 × 10-¹ moldm-³
In a certain reaction, 27.3 g of iron reacts with 45.8 g of oxygen. What is the limiting reactant?
The limiting reactant for the reaction between 27.3 g of iron and 45.8 g of oxygen is iron
Balanced equationWe'll begin by writing the balanced equation for the reaction between iron and oxygen. This is given below:
4Fe + 3O₂ --> 2Fe₂O₃
Molar mass of Fe = 56 g/mol
Mass of Fe from the balanced equation = 4 × 56 = 224 g
Molar mass of O₂ = 16 × 2 = 32 g/mol
Mass of O₂ from the balanced equation = 3 × 32 = 96 g
SUMMARY
From the balanced equation above,
224 g of Fe reacted with 96 g of O₂
How to determine the limiting reactantThe limiting reactant can be obtain as illustrated below:
From the balanced equation above,
224 g of Fe reacted with 96 g of O₂
Therefore,
27.3 g of Fe will react with = (27.3 × 96) / 224 = 11.7 g of O₂
From the calculation above, we can see that only 11.7 g of O₂ out of 45.8 g given is required to react completely with 27.3 g of Fe.
Thus, Fe is the limiting reactant.
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A certain radioactive isotope has a half life of one hour. I you start with 1.0 g of the material at 1:00 P. M., how many grams will be present at 2:00 P. M. on the same day
A certain radioactive isotope has a half life of one hour. I you start with 1.0 g of the material at 1:00 P. M. 0.5 grams will be present at 2:00 P.M. on the same day.
What is half Life ?Half life is the amount of time required to reduce to one half of its initial value. The symbol of half life is [tex]t_{1/2}[/tex].
How to calculate the quantity remaining when half life given ?It is expressed as:
[tex]N_{t} = N_{0} (\frac{1}{2})^{n}[/tex]
where,
N(t) = quantity remaining
N₀ = initial quantity
n = half life that have passed
Now put the values in above expression we get
[tex]N_{t} = 1.0\ g \times (\frac{1}{2})^{1}[/tex]
= [tex]\frac{1}{2} g[/tex]
= 0.5 gram
Thus from the above conclusion we can say that A certain radioactive isotope has a half life of one hour. I you start with 1.0 g of the material at 1:00 P. M. 0.5 grams will be present at 2:00 P.M. on the same day.
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You can practice converting between the mass of a solution and mass of solute when the mass percent concentration of a solution is known. The concentration of the KCN solution given in Part A corresponds to a mass percent of 0.208 % . What mass of a 0.208 % KCN solution contains 914 mg of KCN ? Express the mass to three significant figures and include the appropriate units.
The mass of the solution will be 4,394 mg
Mass percentThe mass percent of a component in a solution can be derived as follows:
Mass percent = mass of component/total mass of solution x 100%
In this case, the mass percent of KCN in the solution is 0.208 and the mass of KCN is 914 mg.
The mass of the 0.208% KCN solution will be:
914/0.208 = 4,394 mg
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A helium balloon has a volume of 2600 cm 3 when the temperature is 21°C. What is the
volume of the balloon when it's placed in a freezer with a temperature of -15°C?
Answer:
2,282 cm³
Explanation:
If all other variables are being held constant, you can find the new volume of the balloon using the Charles' Law equation. The equation looks like this:
V₁ / T₁ = V₂ / T₂
In this equation, "V₁" and "T₁" represent the initial volume and temperature. "V₂" and "T₂" represent the final volume and temperature. Before you can solve for the new volume, you need to convert Celsius to Kelvin (negative values do not work in this equation). This can be done by adding 273.15 to each temperature.
V₁ = 2600 cm³ V₂ = ? cm³
T₁ = 21 °C + 273.15 = 294.15 K T₂ = -15 °C + 273.15 = 258.15 K
V₁ / T₁ = V₂ / T₂ <----- Charles' Law
(2600 cm³) / (294.15 K) = V₂ / (258.15 K) <----- Insert values
8.839 = V₂ / (258.15 K) <----- Simplify left side
2282 = V₂ <----- Multiply both sides by 258.15
The enthalpy of vaporization of Bromine is 15.4 kJ/mol. What is the energy change when 80.2 g of Br2 condenses to a liquid at 59.5°C?
The enthalpy of vaporization of Bromine is 15.4 kJ/mol. -7.7 kJ is the energy change when 80.2 g of Br₂ condenses to a liquid at 59.5°C.
What is Enthalpy of Vaporization ?The amount of enthalpy or energy that must be added to a liquid substance into gas substance is called Enthalpy of Vaporization. It is also known as Latent heat of vaporization.
How to find the energy change from enthalpy of vaporization ?To calculate the energy use this expression:
[tex]Q = n \Delta H_{\text{vapo.}[/tex]
where,
Q = Energy change
n = number of moles
[tex]\Delta H_{\text{Vapo.}}[/tex] = Molar enthalpy of vaporization
Now find the number of moles
Number of moles (n) = [tex]\frac{\text{Given Mass}}{\text{Molar mass}}[/tex]
= [tex]\frac{80.2\ g }{159.8\ g/mol}[/tex]
= 0.5 mol
Now put the values in above formula we get
[tex]Q = - n \Delta H_{\text{vapo.}[/tex] [Negative sign is used because Br₂ condensed here]
= - (0.5 mol × 15.4 kJ/mol)
= - 7.7 kJ
Thus from the above conclusion we can say that The enthalpy of vaporization of Bromine is 15.4 kJ/mol. -7.7 kJ is the energy change when 80.2 g of Br₂ condenses to a liquid at 59.5°C.
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A student dissolves a mass of ammonium nitrate in water and notices that the temperature of the mixture decreases by
2.7 °C. The student concludes that the process of dissolving ammonium nitrate is
The conclusion of the student would be that the dissolution of ammonium nitrate is endothermic.
What are endothermic reactions?They are reactions in which heat is absorbed from the surrounding. The consequence is that the reaction mixture's temperature is always lower.
Thus, the energy of the products is always higher than the energy of the reactants in endothermic reactions.
For endothermic reactions, the enthalpy change is always positive.
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Water is the ______ in aqueous solutions because it can dissolve polar molecules.
Answer:
solvent
Explanation:
Water dissolves the substances, which become the solutes in the solution.
If you react 1.50 mL of cyclohexanol, which has a density of 0.9624 g/mL, with 1.24 mL of 85% phosphoric acid, which has a density of 1.6845 g/mL, what is the theoretical yield (in g) of cyclohexene
the theoretical yield of cyclohexene 1.24ml as phosphoric acid acts as limiting reagent.
What is Limiting Reagent?When a chemical reaction is complete, the limiting reagent—also known as the limiting reactant or limiting agent—is the reactant that has been completely consumed.Since the reaction cannot proceed without this reagent, the amount of product that can be produced is constrained.Excess reagents or excess reactants are any reagents that are present in amounts greater than those necessary to cause a reaction with the limiting reagent (sometimes abbreviated as "xs").The theoretical yield is the quantity of product obtained when the limiting reagent reacts completely, hence it is necessary to identify the limiting reagent in order to compute the percentage yield of a reaction.To learn more about limiting reagent with the given link
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5. A 180 mL disinfectant solution contains 85 mL of isopropyl alcohol. Determine the V/V
concentration of this solution.
The % V/V concentration of a 180-mL disinfectant solution containing 85 mL of isopropyl alcohol is 47 % V/V.
What is the % V/V concentration?It refers to the milliliters of solute for every 100 milliliters of solution.
We have 180 mL of a disinfectant solution that contains 85 mL of isopropyl alcohol (solute).
The % V/V concentration of this solution is:
% V/V = (mL solute/mL solution) × 100% =
% V/V = (85 mL/180 mL) × 100% = 47% V/V
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what is saturated solution?12
Answer:
A solution in which the maximum amount of solvent has been dissolved
Explanation:
For example, 36g of salt in 100g of water.
Hurricanes derive their energy from: Group of answer choices the latent heat of condensation. the latent heat of fusion. the latent heat of sublimation. the latent heat of vaporization.
Hurricanes derive their energy from the Latent heat of condensation.
Hence, Option (1) is correct answer.
What is Latent Heat ?The heat that is released or absorbed during a phase change of a substance is known as Latent heat.
What is Hurricanes ?Hurricanes is basically a type of storm called a tropical cyclone. These are intense low pressure areas. Hurricanes derive their energy from the latent heat of CONDENSATION.
Thus from the above conclusion we can say that Hurricanes derive their energy from the Latent heat of condensation.
Hence, Option (1) is correct answer.
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Element m reacts with fluorine to form an ionic compound with the formula mf4. the m cation has 18 electrons. element m is:____.
Element M reacts with fluorine to form an ionic compound with the formula MF₄. The M cation has 18 electrons. Element M is Sn.
What is Ionic Compound ?An ionic compound is defined as the compound made up of ions that formed charge particles when an atom loses or gains electrons.
What is Cation ?Cations are positively charged ions. It forms when an element lose one or more electrons.
The cation which has 18 electrons is Sn. Sn react with fluorine to form an ionic compound with the formula SnF₄ because Sn is large and F is very small in size.
Thus from the above conclusion we can say that Element M reacts with fluorine to form an ionic compound with the formula MF₄. The M cation has 18 electrons. Element M is Sn.
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The first word in the name of an ester is derived from the ________ used in the esterification.
The first word in the name of an ester is derived from the alcohol used in the esterification.
What is esterification?Esterification is a chemical process where an organic acid with the formula is combined with an alcohol molecule having the chemical formula (ROH).
The process of esterification is known to produce an ester molecule and during this phenomenon is released water (H2O).
An example of an esterification reaction occurs when ethanoic acid (i.e., the active ingredient of vinegar) can react with C2H5OH (i.e., ethanol) in order to form the ethyl ethanoate molecule, which is a well-known ester molecule.
In conclusion, the first word in the name of an ester is derived from the Alcohol used in the esterification.
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6. M = mol solute
L solution
Rewrite this expression for L solution.
Answer:
L = mol solute / M
Explanation:
To rewrite the equation for liters (L), you need to:
M = mol solute / L <----- Given equation
M x L = mol solute <----- Multiply both sides by L
L = mol solute / M <----- Divide both sides by M
Ethanol is one of many toxic substances found in tobacco smoke.
a. True
b. False
The statement is False.
Ethanol is one of many toxic substances found in tobacco smoke.
Ethanol is used in the manufacture of drugs, plastics, lacquers, polishes, plasticizers, and cosmetics. Ethanol is utilized in remedy as a topical antiinfective, and as an antidote for ethylene glycol or methanol overdose.
Ethanol is a natural chemical compound. it's far simple alcohol with the chemical formula C₂H₆O. Its system can be additionally written as CH ₃−CH ₂−OH or C ₂H ₅OH and is frequently abbreviated as EtOH. Ethanol is a risky, flammable, colorless liquid with a characteristic wine-like smell and pungent taste.
Within the worst instances, there can also be respiratory problems, low blood strain, incontinence coronary heart troubles, blood troubles, liver damage, and loss of life. Ethanol can also dry out and worsen the skin; there may be aches, redness, and swelling. Eye publicity to ethanol also can purpose tearing, burning, and stinging.
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Select the correct answer.
Given:
2AI + 6HCI-2AlCl3 + 3H2
If the chemical reaction produces 129 grams of AlCl3, how many grams of H₂ are also produced?
OA 1.22
OB. 2.92
OC. 3.02
OD. 3.65
Answer:
B.) 2.92
Explanation:
Tp find the mass of H₂ produced, you need to (1) convert grams AlCl₃ to moles AlCl₃ (via molar mass), then (2) convert moles AlCl₃ to moles H₂ (via mole-to-mole ratio from equation coefficients), and then (3) convert moles H₂ to grams H₂ (via molar mass). It is important to arrange the ratios/conversions in a way that allows for the cancellation of units.
Molar Mass (AlCl₃): 26.982 g/mol + 3(35.453 g/mol)
Molar Mass (AlCl₃): 133.341 g/mol
2 Al + 6 HCl ---> 2 AlCl₃ + 3 H₂
Molar Mass (H₂): 2(1.008 g/mol)
Molar Mass (H₂): 2.016 g/mol
129 g AlCl₃ 1 mole 3 moles H₂ 2.016 g
------------------ x ------------------ x --------------------- x --------------- =
133.341 g 2 moles AlCl₃ 1 mole
= 2.93 g H₂
*our answers are most likely different due to using slightly different molar masses
What would be the molecular formula of rose oxide which contains C, H, and O and has two degrees of unsaturation and a molecular ion in its mass spectrum at m/z
The molecular formula of rose oxide:
The formula of rose oxide will be [tex]C_{10}H_{18}O[/tex].
What is the molecular formula?
An expression known as the molecular formula describes how many atoms of each element are present in a single compound's molecule. It shows the exact number of atoms in every molecule.
Use the rule of thirteen to obtain the molecular formula for a chemical whose molecular mass is known. Follow these procedures to obtain the molecular formula:
To get the fundamental formula, multiply the molar mass by 13. (sum of the masses of one carbon atom and one hydrogen atom)
Molecular mass/ 13 = n + r/13
where, n = numerator and r = remainder
Base formula is [tex]C_{n}H_{n+r}[/tex]
Calculation:
Remove the mass of the carbon and hydrogen compound that belongs to the same group as the additional atoms if the molecular formula contains atoms in addition to carbon and hydrogen.
Molecular mass /13 = 154/13
= 11 x 13 = 143
Thus, 11 non-H atoms are 11C.
Thus, the formula is [tex]C_{11}H_{11+11} = C_{11}H_{22}[/tex]
If oxygen, is present then the mass is 16 and remove [tex]CH_{4}[/tex].
[tex]C_{11}H_{22} - CH_{4} + O = C_{10}H_{18}O[/tex]
Thus, the formula of the compound will be [tex]C_{10}H_{18}O[/tex]
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11.A student titrated a diprotic weak acid (H2A) with 0.100 M NaOH. The titration required 22.58 mL of NaOH solution to reach the equivalence point. How many moles of diprotic acid were present
Moles of diprotic acid present were:
A mole of diprotic acid contains 0.0023 moles [tex]H_{2}A[/tex].
Law of dilution:
Titrations are conducted using the law of dilution.
The number of moles of solute divided by the arrangement's volume in liters is known as molarity.
The number of moles per liter of solution is referred to as molarity. Additionally, we write it as M. Furthermore, we employ the following equation to determine molarity:
Molarity = moles of solute/liter of solution.
Calculation:
Moles of acid = moles of base
n = M/V
Moles of [tex]H_{2}A[/tex] = Moles of NaOH used
Therefore, 0.100 x 0.02258L = 0.0023 mol [tex]H_{2}A[/tex]
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how the molecule’s properties affect the physical properties of a molecule
The intermolecular forces, such as hydrogen bonds or van der Waals attractions, which draw one molecule to its neighbors, govern a substance's physical properties. Due to the relatively weak intermolecular forces of attraction, molecular substances typically take the form of gases, liquids, or low melting point solids.
How do the intermolecular forces affect physical properties?The forces that bind two molecules together are known as intermolecular forces. Intermolecular forces have an impact on physical properties. Strong and weak forces both exist; the stronger the force, the more energy is needed to separate the molecules from one another. As intermolecular forces increase melting, boiling, and freezing points rise.
The following intermolecular forces are listed in order of strength:
Van der Waals dispersion forcesVan der Waals dipole-dipole interactionsHydrogen bondingIonic bondsIt would take very little energy to separate two molecules if they are connected by van der Waals dispersion forces. On the other hand, it requires a lot more energy to separate two molecules that are joined together by ionic bonds.
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Based on the melting points of both substances in comparison with the table what's your guess
Based on the melting points of both substances in comparison, my guess is Sodium chloride and glucose are the mystery compounds.This is further explained below.
What is Sodium chloride?Generally, Salt's chemical name is sodium chloride. It is an electrolyte's job to keep your body's fluid balance in check.
In conclusion, Sodium chloride and glucose are the likely candidates based on their relative melting points.
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What is surface tension? what is the relationship between intermolecular forces and surface tension? how does surface tension change with temperature?
Because of its molecule's cohesive nature, surface tension has the quality to resist an external force.
Surface tension is simply a property of the surface of a liquid that allows it to resist an external force.
If the intermolecular forces are stronger further results in higher surface tension. For example; water has a high surface tension resulting in strong dipole intermolecular forces. Another example is oil. Oil has a low surface tension resulting in lower dipole intermolecular forces.
Temperature is inversely proportional to Surface tension. Therefore, surface tension increases as the temperature decreases.
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A glass column is filled with mercury and inverted in a pool of mercury. The mercury column stabilizes at a height of 729 mm above the pool of mercury. What is the pressure of the atmosphere
The atmospheric pressure will be:
The pressure of the atmosphere resulting from the mercury column is 0.959 atm
What is atmospheric pressure?
The force that an object experiences from the weight of the air above it per unit area are known as atmospheric pressure.
Given: Height of mercury column = 729 mm Hg
To find: The pressure of the atmosphere
Calculation:
The atmospheric column resulting from the mercury column is calculated as follows:
1 atm =760 mm Hg
So, we can convert the 729 mm Hg to atm, and we get
Atmospheric pressure = 729 x 1 atm / 760 = 0.959 atm
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