Answers
Answer:
4= Si
5=P
3= Al
6= S
2= Mg
Explanation:
4 → Si
Silicon is part of the carbon group and has 14 electrons, spread over 3 shells:
⇒ on the first shell (K) 2 electrons
⇒on the second shell (L) 8 electrons
⇒ on the third shell (M) the remaining electrons : 14-8-2 = 4
5 → P
phosphorus is part of the nitrogen group and has 15 electrons, spread over 3 shells:
⇒ on the first shell (K) 2 electrons
⇒on the second shell (L) 8 electrons
⇒ on the third shell (M) the remaining electrons : 15-8-2 = 5
3 → Al
Aluminium is part of the Boron group and has 13 electrons, spread over 3 shells:
⇒ on the first shell (K) 2 electrons
⇒on the second shell (L) 8 electrons
⇒ on the third shell (M) the remaining electrons : 13-8-2 = 3
6 → S
Sulfur is part of the oxygen group and has 16 electrons, spread over 3 shells:
⇒ on the first shell (K) 2 electrons
⇒on the second shell (L) 8 electrons
⇒ on the third shell (M) the remaining electrons : 16-8-2 = 6
2 → Mg
Magnesium is part of the Beryllium or alkaline earth metals group and has 12 electrons, spread over 3 shells:
⇒ on the first shell (K) 2 electrons
⇒on the second shell (L) 8 electrons
⇒ on the third shell (M) the remaining electrons : 12-8-2 = 2
The completed pairs of element with the number of valence electrons are:
aluminum ⇒ 3sulfur ⇒ 6sodium ⇒ 1silicon ⇒ 4magnesium ⇒ 2phosphorus ⇒ 5What are these valence electrons?Valence electrons are the electrons in the outermost shell of an atom that can participate in chemical bonding. The number of valence electrons an element has determines its chemical properties.
For example, sodium (Na) has 1 valence electron, which it can donate to other atoms to form bonds. This is why sodium is a reactive metal.
Sulfur (S) has 6 valence electrons, which it can share with other atoms to form bonds. This is why sulfur can form a variety of compounds with other elements.
The number of valence electrons an element has can also be determined by looking at its periodic table group. Elements in the same group have the same number of valence electrons.
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Related Questions
An object with a mass of 100 kg is dropped from a height of 20 m. If the velocity of the object before hitting the ground is 15 m/s, is there a loss of energy in the form of heat? If so, how much? Assume, g= 9.8 m/s^2
Answers
Answer:
Yes, there is a loss of 8350 J of energy in the form of heat
Explanation:
The principle of energy conservation is described mathematically
as the energy conservation equation as follows:
ΔK+ΔU=Q+W
where:
ΔK: changes in kinetics energy [J]ΔU: changes in potential energy [J]Q: gain or loss of heat[J]W: work done by the system or in the system[J]Analyzing each term of the equation:
[tex]ΔK=\frac{1}{2}mv_{f} ^{2} - \x]frac{1}{2}mv_{i} ^{2}=\frac{1}{2}*100*15^{2} - \frac{1}{2}*100*0^{2}=11250 J[/tex]
ΔU=[tex]mgh_{f}-mgh_{i}=100*9,8*0-100*9,8*20=-19600[J][/tex]
Q=?
W=0 [J]
Replacing in the main equation:
11250-19600=Q+0
Q= -8350 [J]
So, the answer is YES, there is a loss of 8350 J of energy in the form of heat.
Consider four small molecules, A–D, which have the following binding affinities for a specific enzyme (these numbers are the equilibrium constants Kd for the dissociation of the enzyme/molecule complex). Which binds most tightly to the enzyme? Which binds least tightly?
A) 4.5 μM
B) 13 nM
C) 8.2 pM
D) 6.9 mM
Answers
Answer:
Binding affinity measures the strength of the interaction between a molecule to its ligand; it is expressed in terms of the equilibrium dissociation constant; and the higher value of this constant, the more weaker the binding between the molecule and the ligand is. On the other hand, small constans means that the interaction is tight. So "C" binds most tightly to the enzyme and "D" binds least tightly.
What masses of monobasic and dibasic sodium phosphate will you use to make 250 mL of 0.1 M sodium phosphate buffer, pH = 7?
Answers
Answer:
Mass of monobasic sodium phosphate = 1.857 g Mass of dibasic sodium phosphate = 1.352 gExplanation:
The equilibrium that takes place is:
H₂PO₄⁻ ↔ HPO₄⁻² + H⁺ pka= 7.21 (we know this from literature)
To solve this problem we use the Henderson–Hasselbalch (H-H) equation:
pH = pka + [tex]log\frac{[A^{-} ]}{[HA]}[/tex]
In this case [A⁻] is [HPO₄⁻²], [HA] is [H₂PO₄⁻], pH=7.0, and pka = 7.21
If we use put data in the H-H equation, and solve for [HPO₄⁻²], we're left with:
[tex]7.0=7.21+log\frac{[HPO4^{-2} ]}{[H2PO4^{-} ]}\\ -0.21=log\frac{[HPO4^{-2} ]}{[H2PO4^{-} ]}\\\\10^{-0.21} =\frac{[HPO4^{-2} ]}{[H2PO4^{-} ]}\\0.616 * [H2PO4^{-}] = [HPO4^{-2}][/tex]
From the problem, we know that [HPO₄⁻²] + [H₂PO₄⁻] = 0.1 M
We replace the value of [HPO₄⁻²] in this equation:
0.616 * [H₂PO₄⁻] + [H₂PO₄⁻] = 0.1 M
1.616 * [H₂PO₄⁻] = 0.1 M
[H₂PO₄⁻] = 0.0619 M
With the value of [H₂PO₄⁻] we can calculate [HPO₄⁻²]:
[HPO₄⁻²] + 0.0619 M = 0.1 M
[HPO₄⁻²] = 0.0381 M
With the concentrations, the volume and the molecular weights, we can calculate the masses:
Molecular weight of monobasic sodium phosphate (NaH₂PO₄)= 120 g/mol.Molecular weight of dibasic sodium phosphate (Na₂HPO₄)= 142 g/mol.mass of NaH₂PO₄ = 0.0619 M * 0.250 L * 120 g/mol = 1.857 gmass of Na₂HPO₄ = 0.0381 M * 0.250 L * 142 g/mol = 1.352 gSketch and label a covalent bond and an ionic bond (you do not need to draw the metallic bond or intermolecular force). Describe the role of electrons in covalent, ionic, and metallic bonds (you do not need to describe the intermolecular force), and describe the strength of these bonds. Also explain (no sketch) how differences in bonds cause diamond and graphite to have very different properties (2.11A).
Answers
Answer:
See attached image
Explanation:
An ionic bond is a type of chemical bond in which occurs an electrons transfer, where one of the atoms act as a donor and the other act as the acceptor. Compound with ionic bonds are very stables and strong because of the attraction of the opposite charges. These attractions help ions stay together forming solid nets.
A covalent bond is a type of chemical bond in which the electrons are shared. Unlike the ionic bond, the atoms act at the same time as donors and acceptors sharing their electrons. The covalent bond keeps the atoms together because an electrostatic force, thus this bond is weaker than the ionic bond.
A metallic bond is a force which keeps together metallic atoms. In this type of bond, there is no transfer or sharing of electrons. The atoms are kept together because of an electrostatic force. Since there is no electron exchange involved a metallic bond is weaker than the other two.
In diamond, every carbon atom shared four electrons with other carbon atoms between a covalent bond. These form a regular tetrahedron. On the other side, graphite has a layer structure, in which every layer hold carbon atoms wich shared electrons with other tree atoms. All the layers stay together because of the Van der Waals force. These difference in bonds cause to have different properties, diamond is one of the hardest materials and graphite it is not.
Reynolds number E. What is the mean velocity u. (ft/s) and the Reynolds number Re = pu., D/ for 35 gpm (gallons per minute) of water flowing in a 1.05- in. ID. pipe if its density is p = 62.3 lb/ft and its viscosity is = 1.2 cP? What are the units of the Reynolds number?
Answers
Answer:
The mean velocity is 13 ft/s.
The Reynolds number is 88,583 and it is dimensionless.
Explanation:
We have water flowing in a pipe of 1.05 in diameter.
The density is ρ=62.3 lb/ft and the viscosity is 1.2 cP.
The mean velocity can be calculated as
[tex]u=\frac{Q}{A}=\frac{Q}{\pi*D^2/4}=\frac{35gpm }{3.14*(1.05in)^2/4}\\\\ u=\frac{35}{0.865}*\frac{gal}{min}\frac{1}{in^2}*\frac{231in^3}{1gal}*\frac{1}{60s} \\\\ u=156\,in/s=13\,ft/s[/tex]
The Reynolds number now can be calculated for this flow as
[tex]Re=\frac{\rho*u*D}{\mu}[/tex]
being ρ: density, u: mean velocity of the fluid, D: internal diameter of the pipe and μ the dynamic viscosity.
To simplify the calculation, we can first make all the variables have coherent units.
Viscosity
[tex]\mu=1.2cP=\frac{1.2}{100}\frac{g}{cm*s}*\frac{1lb}{453.6g}*\frac{30.48cm}{1ft}= 0.0008\frac{lb}{ft*s}[/tex]
Diameter
[tex]D=1.05in*(\frac{1ft}{12in} )=0.0875ft[/tex]
Then the Reynolds number is
[tex]Re=\frac{\rho*u*D}{\mu}\\\\Re=62.3\frac{lb}{ft^3}*13\frac{ft}{s} *0.0875ft*\frac{1}{0.0008}*\frac{ft*s}{lb}\\\\Re=88,583[/tex]
The Reynolds number (Re) and mean velocity (u) for water flowing through a pipe can be calculated using the flow rate, pipe dimensions, fluid density, and viscosity. The Reynolds number is a dimensionless quantity that helps predict the flow pattern in the pipe.
Explanation:The question relates to the calculation of the Reynolds number and the mean velocity (u) for a given flow rate of water through a pipe. First, to find the mean velocity u, the flow rate needs to be converted to cubic feet per second (ft³/s) and then divided by the cross-sectional area of the pipe. The Reynolds number Re is a dimensionless number used to predict flow patterns in different fluid flow situations. It is calculated using the formula Re = ρuD/μ, where ρ is the fluid density, u is the mean velocity, D is the pipe diameter, and μ is the dynamic viscosity of the fluid.
To proceed with the calculation, the given flow rate of 35 gallons per minute (gpm) is converted to cubic feet per second, the pipe's internal diameter is converted to feet, the density of water (62.3 lb/ft³) is used, and the viscosity (1.2 cP) is converted to lb/(ft·s). The mean velocity u is then calculated, and subsequently, the Reynolds number Re is determined.
The units of the Reynolds number are indeed unitless, as demonstrated by the cancellation of units in its definition, ensuring it is a dimensionless quantity.
How to dispose chemical waste? If unsure what should you do?
Answers
Identifying the Proper Waste Disposal Method
Read the material safety data sheet.
chemical products come with disposal instructions right on the label and following those instructions should be enough. Even for products without disposal instructions, you should still read the labels so you can be aware of the warnings and cautions concerning said products.
Items such as batteries and light bulbs have to be recycled at special recycling centers.
Never mix cleaning products together. If you only have a small amount of cleaning product left in each bottle, it may be tempting to mix them into one bottle for disposal. Different chemicals can react with each other to form very hazardous fumes and noxious gases.
Search the list of hazardous waste
In addition to the product label, you want to read the MSDS for industrial chemicals. The MSDS gives you important information about the chemical: its toxicity, reactivity, and disposal considerations.
Every chemical product you buy should come with an MSDS sheet. However, you can also use the online MSDS database to look up the MSDS for the specific formulation of the chemical you wish to dispose.[1]
Search the list of hazardous wastes
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Sorry that’s all I know :)
A 36.5 lb child has a Streptococcus infection. Amoxicillin is prescribed at a dosage of 25 mg per kg of body.How many hours should pass between each administration?number of hours:Amoxicillin should be stored between 0 °C and 20 °C. Should the amoxicillin be stored in the freezer or the refrigerator?
Answers
Answer:
36.5 lbs weight of child able to take 413.91 mg/ day dose
Amoxicillin should be stored in temperature 0°C to 20°C, therefore it must be stores in refrigerator as it provided temperature only between 0°C to 5°C.
Explanation:
Given data:
Dosage of Amoxicillin as prescribed is 25 mg/kg-day
Weight of the Child weight = 36.5 lbs
As We know 1 lbs = 0.4536 kg
therefore, the weight of Child is 36.5\times 0.4536 kg = 16.5564 kg
From the information about dosage,
1 kg of body takes = 25 mg/day
so, for 16.556 kg body [tex]16.5564\ kg \ body\ takes = 25\times 16.5564 = 413.91 mg/day[/tex]
Therefore 36.5 lbs weight of child able to take 413.91 mg/ day dose
Amoxicillin should be stored in temperature 0°C to 20°C, therefore it must be stored in refrigerator as it provided temperature only between 0°C to 5°C.
Final answer:
To calculate the amoxicillin dosage for a child, convert the child's weight to kilograms, multiply by the prescribed mg/kg dosage, then divide by the tablet strength. Amoxicillin should be stored in a refrigerator, not a freezer.
Explanation:
The question relates to the prescription and administration of amoxicillin dosage based on a patient's weight. To determine the number of tablets to administer, you will need to convert the child's weight from pounds to kilograms (1 pound = 0.453592 kg), multiply the child's weight in kilograms by the prescribed dosage per kilogram and then divide the total dosage by the amount of medicine per tablet.
Using the information provided, if a doctor prescribes amoxicillin at 30mg/kg to a child weighing 73.5 lbs, first convert the weight: 73.5 lbs × 0.453592 = 33.3 kg approximately. Next, calculate the total dosage: 33.3 kg × 30 mg/kg = 999 mg. Since amoxicillin is available in 500 mg tablets, divide the total dosage by the tablet strength: 999 mg / 500 mg/tablet = about 2 tablets (always round to the nearest whole number when it involves whole tablets).
Amoxicillin should be stored between 0 °C and 20 °C, which is typically within the temperature range of a refrigerator, not a freezer. Therefore, amoxicillin should be stored in the refrigerator to maintain its efficacy.
Tell why you may be able to survive a bitter cold day in snow-cave."
Answers
Answer:
First you need to know that the warm air is less dense than the colder air and thus it tends to rise; so snow-caves are constructed in some way that the tunnel entrance is below the main space, and so the warm air can be retained into the cave. In a typical snow-cave, you can reach temperatures over 0°C even when the temperature outside are under zero degrees celsius.
Part B Compute 1240.64/64. Round the answer appropriately Express your answer numerically using the proper number of significant figures. View Available Hint(s) Submit
Answers
Answer:
19
Explanation:
1240.64/64
This is a simple division that can easily be evaluated using any form of calculator.
Here, the main challenge is in expressing the answer in the proper number of significant figure.
The approach here is to express the answer to the which is least precise. This is usually the number with the lower significant values.
Here, 64 has two significant figures and it is of a lower rank. Our answer should be expressed this way:
[tex]\frac{1240.64}{64}[/tex] = 19.385 = 19
Of the two type of bonds (pi and sigma), which is capable of rotation around that bond and which is not? Why?
Answers
Answer:
The sigma bonds are capable of rotating, the pi bonds not.
Explanation:
Sigma bonds are the strongest type of bonds, there are related to the overlapping in the atomic orbitals, and they can rotate. In the pi bound (that is a double bond), there are electrons moving on the molecule and it is not permitted the rotation on this type of bonds. Of the sigma bonds are capable of rotating while the pi bonds not.
You are performing a chemical reaction in a test tube. The test tube gets colder as the reaction takes place. This chemical reaction is... O a.a double replacement reaction. O b.endothermic Oc.a single replacement reaction. O d.a decomposition reaction. e. exothermic
Answers
Answer: Option (b) is the correct answer.
Explanation:
A chemical reaction in which heat energy is absorbed by the reactant molecules is known as an endothermic reaction.
Therefore, upon completion of this reaction the container in which reaction is carried out becomes colder.
A chemical reaction in which heat energy is released by the reactant molecules is known as an exothermic reaction.
Therefore, upon completion or during this type of reaction the container in which reaction is carried out becomes hot.
Thus, we can conclude that when the test tube gets colder as the reaction takes place then it means this chemical reaction is endothermic reaction.
At 1.00 atmosphere pressure, a certain mass of a gas has a temperature of 100oC. What will be the temperature at 1.13 atmosphere pressure if the volume remains constant?
Answers
Answer: Final temperature of the gas will be 330 K.
Explanation:
Gay-Lussac's Law: This law states that pressure is directly proportional to the temperature of the gas at constant volume and number of moles.
[tex]P\propto T[/tex] (At constant volume and number of moles)
[tex]{P_1\times T_1}={P_2\times T_2}[/tex]
where,
[tex]P_1[/tex] = initial pressure of gas = 1.00 atm
[tex]P_2[/tex] = final pressure of gas = 1.13 atm
[tex]T_1[/tex] = initial temperature of gas = [tex]100^0C=(100+273)K=373K[/tex] K
[tex]T_2[/tex] = final temperature of gas = ?
[tex]{1.00\times 373}={1.13\times T_2}[/tex]
[tex]T_2=330K[/tex]
Therefore, the final temperature of the gas will be 330 K.
If light moves at a speed of about 3.00 x 108 m/s, how long will it take light to travel the distance of a marathon (about 42.2 km)? Express your answer in microseconds using the correct number of significant figures. Do not enter your answer using scientific notation.
Answers
Light travels a distance of 3.69 meters within the given time frame of 12.3 nanoseconds.
Speed is the measure of how quickly an object changes its position concerning a specified frame of reference. It's a scalar quantity, indicating both magnitude and direction.
Common units for speed include meters per second (m/s) or kilometers per hour (km/h). This fundamental concept plays a pivotal role in various domains like travel, sports, and transportation.
If light travels at a constant speed of [tex]3.0 * 10^8 m/s[/tex] and continues for 12.3 nanoseconds, the distance covered can be calculated:
Distance = Speed × Time
Distance = [tex]3.0 * 10^8 m/s* 12.3 * 10^{-9} s[/tex]
Distance = 3.69 meters
In this instance, light travels a distance of 3.69 meters within the given time frame of 12.3 nanoseconds.
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A medium-sized carrot weighs 64 g and contains 7.0 g of carbohydrate.
What percent, by mass, of the carrot is carbohydrate? Express your answer using two significant figures.
Answers
Answer:
10,93% of a carrot is carbohydrate.
Explanation:
In order to solve this you just have to create a rule of three where 64g is the 100% and you want to calculate how much is 7g in percentage:
[tex]\frac{64}{100}= \frac{7}{x}\\ x=\frac{7*100}{64}\\ x=10,9375[/tex]
So there are 10.9375 % carbohydrates in a piece of carrot.
The percent, by mass, of carbohydrate in a medium-sized carrot is approximately 10.9%.
Explanation:To find the percent, by mass, of carbohydrate in a medium-sized carrot, we can use the following formula:
Percent mass of carbohydrate = (mass of carbohydrate / total mass) × 100
In this case, the mass of carbohydrate is given as 7.0 g and the total mass of the carrot is 64 g. Plugging these values into the formula:
Percent mass of carbohydrate = (7.0 g / 64 g) × 100 = 10.9%
Therefore, approximately 10.9% of the carrot's mass is carbohydrate.
A candidate material for a turbine blade application oxidizes by diffusion of metal atoms through the oxide to the metal surface, where metal and oxygen react to form the oxide. After 10 hours at 550°C, an oxide layer 8 um has formed. What will the thickness be after 100 hours. (hint: turbine blade can be considered as a cylinder)
Answers
Answer:
The thickness of the oxide layer will 80 μm after 100 hours.
Explanation:
Thickness of oxide layer in 10 hours= 8 μm
Thickness of oxide layer in 1 hour = [tex]\frac{8 \mu m}{10 hour}[/tex]
Thickness of oxide layer in 100 hour :
[tex]\frac{8 \mu m}{10 hour}\times 100=80 \mu m[/tex]
The thickness of the oxide layer will 80 μm after 100 hours.
Consider the following reaction: A+B C +D a) What is the correct expression for the equilibrium constant (k)? b) The k value for this reaction is 45000. What does this tell you about the reaction? c) If the Ris 45000 are the reactants more stable than the products?
Answers
Answer:
a) k = [tex]\frac{[C][D]}{[A][B]}[/tex]
b) A value of 45000 means that tendency of your reaction is to have more products in a ratio of 45000:1
c) No, the products are more stable than reactants.
Explanation:
a) For a reaction:
A + B → C + D
The equlibrium constant (k) is:
k = [tex]\frac{[C][D]}{[A][B]}[/tex]
Where [x] is the molar concentration of x. Always the expression of equilibrium constant is molar concentration of products over molar concentration of reagents.
b) Having in mind the expression of equilibrium constant when k>1 the concentration of products is higher than concentration of reagents. Thus, when k<1 concentration of reagents is higher than concentration of products.
A value of 45000 means that tendency of your reaction is to have more products in a ratio of 45000:1
c) Again, a value of 45000 means that tendency of your reactants is react to produce products. Thus, the products are more stable than reactants.
I hope it helps!
Match with the correct definition.
A.
Each electron state can hold no more than two electrons, which must have opposite spins.
B.
Electron sharing between two adjacent atoms such that each atom assumes a stable electron configuration.
C.
Electrostatic attraction between oppositely charged ions.
D.
The positively charged ion cores are shielded from one another, and also "glued" together by the sea of valence electrons.
Ionic bonding: A, B, C, or D?
Covalent Bonding: A,B,C or, D?
Metallic bonding: A, B, C, or D?
Pauli exclusion principle: A, B C, or D?
Answers
Answer:
Ionic bonding: C
Covalent bonding: B
Metallic bonding: D
Pauli exclusion principle: A
Explanation:
All the electrons in 1 atom are characterized by a series of 4 numbers, known as quantum numbers. These numbers (n, l, ml, ms) describe the state of each electron (in which level, sublevel, orbital it is and its spin). For 2 electrons to coexist in the same atom they must differ in at least of these numbers. If they occupy the same level, sublevel and orbital, then they must have different (and opposite) spins. This is known as Pauli exclusion principle.
Also, to gain stability atoms can gain, lose or share electrons. In doing so they form bonds. There are 3 kinds of bonds:
Ionic bonding: these are formed between metals and nonmetals. Metals tend to lose electrons and form cations (positive ions) and nonmetals tend to gain electrons and form anions (negative ions). Cations and anions attract each other due to electrostatic forces between oppositely charged ions.Covalent bonding: these are formed between nonmetals, which share pairs of electrons so as to reach the electron configuration of the closest noble gas (the most stable electron configuration).Metallic bonding: valence electrons are loose in metals, so they move together as a "sea of electrons", acting as "glue" of the remaining positive cores (electrons that are negative charges serve to attract the positive charges of the cores).Name the following ternary acids. a. H2 SO4 e. HMnO4 i. HNO2 m. HClO4 b. H2 SO3 f. H2 CrO4 j. H2 CO3 n. HClO3 c. H2 S2 O3 g. H3 BO3 k. H2 C2 O4 o. HClO2 d. H3 PO4 h. HNO3 l. CH3 COOH p. HClO
Answers
Answer:
H2 SO4 (Sulfuric acid) - HMnO4 (Permanganic acid) - HNO2 (Nitrous acid) HClO4 (Perchloric acid) - H2 SO3 (Sulphurous acid) - H2CrO4 (Chromic acid) H2CO3 (Carbonic acid) - HClO3 (Chloric acid) - H3BO3 (boric acid) - HClO2 (Chlorous acid) H3PO4 (Phosphoric acid) HNO3 (Nitric acid) - HClO (Hypochlorous acid) - CH3 COOH (acetic acid) - H2S2O3 (Thiosulfuric acid)- H2C2O4 (oxalic acid)
Explanation:
To name the ternary acid, they have to obbey the following formula
Hx - Non metal - Oy
where the oxidation state in H and O are +1 y -2 respectively.
When the oxidation state of the central Non metal is odd, the atomicity of H is 1 and in the O is deduced in such a way that the sum of oxidation states is 0.
When the oxidation state of the central No metal is even, the atomicity of H is 2 and in the O is deduced in such a way that the sum of oxidation states is 0.
IV V VI VII
- - 1 Hypo ……. Ous
- 3 4 3 … ous
4 5 6 5 … ic
7 Per …… Ous
The oxalic acid is an organic compound of two carboxyl groups, so it is also called ethanedioc acid; It is actually known as oxalic by some plants of the genus oxalis. (prefix et (2 carbons))
The acetic acid that comprises a carboxylic group and a methyl group is also an organic compound. It is popularly known as acetic acid but it is actually called methylcarboxylic acid or having two carbons, ethanoic acid.
List in order the 9 most electronegative elements of the periodic table
Answers
Answer:
F (3.98)> O (3.44)> Cl (3.16)> N (3.04)> Kr (3.00)> Br (2.96)> I (2.66)> Xe (2.6)> S(2.58)
Explanation:
Electronegativity is described as the tendency or ability of an element to attract electron density or bond pair of electrons towards itself. It is a chemical property of an element.
In the periodic table, the least electronegative element is caesium (0.79) and the most electronegative element is fluorine (3.98).
List of 9 most electronegative elements are:
F (3.98)> O (3.44)> Cl (3.16)> N (3.04)> Kr (3.00)> Br (2.96)> I (2.66)> Xe (2.6)> S(2.58).
You have 15.42g of C2H6. How many moles of H2O can be made?
Answers
Answer: The moles of water produced are 1.54 moles.
Explanation:
To calculate the number of moles, we use the equation:
[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}[/tex]
Given mass of ethane = 15.42 g
Molar mass of ethane = 30.07 g/mol
Putting values in above equation, we get:
[tex]\text{Moles of ethane}=\frac{15.42g}{30.07g/mol}=0.513mol[/tex]
The chemical equation for the combustion of ethane follows:
[tex]2C_2H_6+5O_2\rightarrow 4CO2+6H_2O[/tex]
By Stoichiometry of the reaction:
2 moles of ethane produces 6 moles of water
So, 0.513 moles of ethane will produce = [tex]\frac{6}{2}\times 0.513=1.54mol[/tex] of water
Hence, the moles of water produced are 1.54 moles.
Just as the depletion of stratospheric ozone threatens life on Earth today, its accumulation was one of the crucial processes that allowed life to develop in prehistoric times: 3O2(g) → 2O3(g) At a given instant, the reaction rate in terms of [O2] is 2.17 × 10−5 mol/L·s. What is it in terms of [O3]? Enter your answer in scientific notation.
Answers
Answer:
Rate in terms of formation of [tex]O_{3}[/tex] is [tex]1.45\times 10^{-5}mol/L.s[/tex]
Explanation:
According to law of mass action for this reaction: Rate = [tex]-\frac{1}{3}\frac{\Delta [O_{2}]}{\Delta t}=\frac{1}{2}\frac{\Delta [O_{3}]}{\Delta t}[/tex][tex]-\frac{\Delta [O_{2}]}{\Delta t}[/tex] represents rate of disappearance of [tex]O_{2}[/tex] and [tex]\frac{\Delta [O_{3}]}{\Delta t}[/tex] represents rate of formation of [tex]O_{3}[/tex]Here, [tex]-\frac{\Delta [O_{2}]}{\Delta t}=2.17\times 10^{-5}mol/L.s[/tex]So, [tex]\frac{\Delta [O_{3}]}{\Delta t}=\frac{2}{3}\times -\frac{\Delta [O_{2}]}{\Delta t}=\frac{2}{3}\times (2.17\times 10^{-5}mol/L.s)=1.45\times 10^{-5}mol/L.s[/tex]Hence rate in terms of formation of [tex]O_{3}[/tex] is [tex]1.45\times 10^{-5}mol/L.s[/tex]The rate of formation is the time taken by the reaction to yield the product by the chemical change in the reactants. The rate of the formation of the ozone is [tex]1.45 \times 10^{-5} \;\rm mol/Ls[/tex].
What is the law of mass action?The law of mass action states that the rate of the reaction is proportional to the product of the reactant masses.
Rate according to the law of mass action:
[tex]\rm -\dfrac{1}{3}\dfrac {\Delta[O_{2}]}{\Delta t} = \rm \dfrac{1}{2}\dfrac{\Delta [O_{3}]}{\Delta t}[/tex]
Here,
Rate of disappearance of oxygen [tex](\rm -\dfrac {\Delta[O_{2}]}{\Delta t} ) = 2.17 \times 10^{-5} \;\rm mol/Ls[/tex] Rate of formation of ozone =[tex]\rm \dfrac{\Delta [O_{3}]}{\Delta t}[/tex]Substituting values in the above equation:
[tex]\begin{aligned}\rm \dfrac{\Delta [O_{3}]}{\Delta t} &= \dfrac{2}{3}\times - \rm \dfrac{\Delta [O_{2}]}{\Delta t}\\\\&= \dfrac{2}{3} \times (2.17 \times 10^{-5})\\\\&= 1.45 \times 10^{-5}\;\rm mol/Ls\end{aligned}[/tex]
Therefore, the rate of formation in the terms of ozone is [tex]1.45 \times 10^{-5} \;\rm mol/Ls.[/tex]
Learn more about the rate of formation here:
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What is inaccurate about describing a solution as containing or using free hydrogen atoms?
Answers
Answer: An aqueous solution will contains both hydrogen ion and hydroxide ion.An here we are talking about free hydrogen ions, which means the description will be related to the pH. If the ratio of ion are equal then the pH will be 7 i.e. neutral. But if there are free hydrogen atoms in the solution we have, the pH of solution will be less than 7 and the solution will be described ad acidic. So the inaccurate description for a solution containing free hydrogen ion is that it is basic in nature.
Your patient gets a prescription for 62.5 mcg (micrograms, mg) of digoxin in liquid form. The label reads 0.0250 mg/mL. How many milliliters of digoxin should you give?
Answers
Answer:
2.5 militers (mL) of digoxin solution
Explanation:
if 1 microgram = 0.001 miligram
then 62.5 micrograms = X miligrams
X = (62.5 × 0.001) / 1 = 0.0625 miligrams
the we calculate the number of militers of digoxin needed by the patient:
if we have 0.0250 miligrams of digoxin in 1 mililiter of solution
then we have 0.0625 miligrams of digoxin in X mililiters of solution
X = (0.0625 × 1) / 0.0250 = 2.5 militers (mL) of digoxin solution
To calculate the amount of digoxin in milliliters, divide the amount of digoxin in milligrams by the concentration of the liquid form in milligrams per milliliter. In this case, the prescription is for 62.5 mcg of digoxin, and the concentration of the liquid form is 0.0250 mg/mL. The calculated volume of digoxin to be given is 2.5 mL.
Explanation:To calculate the amount of digoxin in milliliters that should be given, we need to use the given information and convert units. The prescription is for 62.5 mcg (micrograms) of digoxin, and the concentration of the liquid form is 0.0250 mg/mL. To convert micrograms to milligrams, we divide by 1000. Then, we can use the formula: Volume (in mL) = Amount (in mg) / Concentration (in mg/mL).
Amount of digoxin in mg = 62.5 mcg / 1000 = 0.0625 mg
Volume of digoxin in mL = 0.0625 mg / 0.0250 mg/mL = 2.5 mL
Convert 59.9 m^2 to square centimeters. cm^2
Answers
Answer:
59.9 m² = 599000 cm²
Explanation:
According to the International System of Units, square metre (m²) is the SI unit of area. 1 m² is defined as the area of the square having sides 1 m long.
Some other units of area are square millimetres (mm²), square kilometres (km²), square centimetres (cm²).
Now, converting square metre (m²) to square centimetres (cm²)
Since, 1 m² = 10⁴ cm²
Therefore, 59.9 m² = 59.9 × 10⁴ cm² = 599000 cm².
Therefore, 59.9 m² = 599000 cm²
A plastic rectangle has dimensions of 1.0 cm, 2.0 cm and 3.0 cm respectively. It masses 5.5 g when placed on an electronic mass balance. What is its density? Would it float in water? Density of water is 1.0 g/mL.
Answers
Answer:
0.917g/cm^3
Explanation:
Density = Mass/ Volume.
Given,
Mass = 5.5g
Volume of the plastic = L*W*H
= 1.0 x 2.0 x 3.0 = 6.0cm^3
Density = Mass/volume
= 5.5g/6.0cm^3
= 0.9166666666
= 0.917g/cm^3
Since the density of water is greater than that of the plastic, it means that the plastic will float in water.
Answer:
Sinking of the block in water will not happen.
Explanation:
An object’s (block in this case) density can be found out by dividing the mass of that object from its volume. In the given question the mass of rectangular block is given as 5.5 gram and the sides of the rectangular block is [tex]1, 2 and 3 cm[/tex] so volume will be [tex]6 cm^3[/tex]
[tex]Density = Mass/ Volume[/tex]
Now to calculate the density [tex]5.5/ 6= 0.91g/ml[/tex]
This block will float on water since the block’s density is less than water.
Air at 293 K and 750 mm Hg pressure has a relative humidity of 80%. What is its percent humidity? The vapour pressure of water at 293 K is 17.5 mm Hg. (a) 80.38 (b) 80 (c) 79.62 (d) 78.51
Answers
Answer : The correct option is, (c) 79.62
Explanation :
The formula used for percent humidity is:
[tex]\text{Percent humidity}=\text{Relative humidity}\times \frac{p-p^o_v}{p-p_v}\times 100[/tex] ..........(1)
The formula used for relative humidity is:
[tex]\text{Relative humidity}=\frac{p_v}{p^o_v}[/tex] ...........(2)
where,
[tex]p_v[/tex] = partial pressure of water vapor
[tex]p^o_v[/tex] = vapor pressure of water
p = total pressure
First we have to calculate the partial pressure of water vapor by using equation 2.
Given:
[tex]p=750mmHg[/tex]
[tex]p^o_v=17.5mmHg[/tex]
Relative humidity = 80 % = 0.80
Now put all the given values in equation 2, we get:
[tex]0.80=\frac{p_v}{17.5mmHg}[/tex]
[tex]p_v=14mmHg[/tex]
Now we have to calculate the percent humidity by using equation 1.
[tex]\text{Percent humidity}=0.80\times \frac{750-17.5}{750-14}\times 100[/tex]
[tex]\text{Percent humidity}=79.62\%[/tex]
Therefore, the percent humidity is 79.62 %
Use the Ref An aqueous solution of chromium(II) acetate has a concentration of 0.260 molal. The percent by mass of chromium(II) acetate in the solution is Submit Answer Retry Entire Group 9 more group attempts remaining
Answers
Answer:
The percent by mass of chromium(II) acetate in the solution is 4.42%.
Explanation:
Molality of the chromium(II) acetate solution = 0.260 m = 0.260 mol/kg
This means that in 1 kg of solution 0.260 moles of chromium(II) acetate are present.
1000 g = 1 kg
So, in 1000 grams of solution 0.260 moles of chromium(II) acetate are present.
Then in 100 grams of solution = [tex]\frac{0.260 mol}{1000}\times 100=0.0260 mol[/tex]
Mass of 0.0260 moles chromium(II) acetate:
= 0.0260 mol × 170 g/mol = 4.42 g
[tex](w/w)\%=\frac{\text{mass of solute in 100 gram solution}}{100}\times 100[/tex]
[tex]=\frac{4.42 g}{100 g}\times 100=4.42\%[/tex]
The percent by mass of chromium(II) acetate in the solution is 4.42%.
In a laboratory experiment, a fermenting aqueous solution of glucose and yeast produces carbon dioxide gas and ethanol. The solution was heated by burning natural gas in a Bunsen burner to distill the ethanol that formed in the flask. During the distillation, the ethanol evaporated and then condensed in the receiving flask. The flame of the burner was kept too close to the bottom of the flask and some of the glucose decomposed into a black carbon deposit on the inside of the flask. During this experiment the following changes occurred. Which of these changes involved a physical change and not a chemical change? Check all that apply. Check all that apply.
1-condensation of ethanol
2-evaporation of ethanol
3- formation of carbon dioxide gas from glucose burning of natural gas
4-formation of ethanol from glucose by yeast
5-formation of a carbon deposit inside the flask
Answers
Answer:
1-condensation of ethanol
2-evaporation of ethanol
Explanation:
According to the question ,
As the compound condenses , it is a basic process of the change in the state , and hence , it is only a physical change . Then , the ethanol is changing its state, hence , again a physical change is observed . The carbon dioxide gas is formed from the glucose would be a chemical change since a new product is formed i.e carbon dioxide , from the reaction between the glucose and yeast . The formation of a carbon deposit was due to the heat which altered the chemical make - up of the substance and is therefore a chemical change .The questions are: Find the equations for the reaction of
HCLwith MgO and HCL and Mg. How the reactions different?
Answers
Answer:
[tex]Mg(s) + HCl(aq) \rightarrow MgCl_2(aq) + H_2(g)[/tex]
[tex]MgO(s) + HCl(aq) \rightarrow MgCl_2(aq) + H_2O(l)[/tex]
Explanation:
When Mg reacts with HCl, magnesium chloride and hydrogen is formed. Mg is an active element and displaces hydrogen from HCl. So, this is a type of single displacement reaction.
[tex]Mg(s) + HCl(aq) \rightarrow MgCl_2(aq) + H_2(g)[/tex]
When magnesium oxide (MgO) reacts with HCl, magnesium chloride and water is formed. This reaction is a type of neutralization reaction. MgO is a water insoluble base and HCl is acid. So. in this reaction, acid reacts with base to form salt [tex]MgCl_2[/tex]
[tex]MgO(s) + HCl(aq) \rightarrow MgCl_2(aq) + H_2O(l)[/tex]
The equation for the reaction between HCl and MgO is 2HCl(aq) + MgO(s) → MgCl2(aq) + H2O(l). The equation for the reaction between HCl and Mg is 2HCl(aq) + Mg(s) → MgCl2(aq) + H2(g). The reactions differ in terms of the reactants involved.
Explanation:The equation for the reaction between HCl and MgO is:
2HCl(aq) + MgO(s) → MgCl2(aq) + H2O(l)
The equation for the reaction between HCl and Mg is:
2HCl(aq) + Mg(s) → MgCl2(aq) + H2(g)
The reactions differ in terms of the reactants involved. In the reaction with MgO, the reactant is an oxide compound (MgO) while in the reaction with Mg, the reactant is a pure metal (Mg).
Carlos Santana is a popular Latin-rock and jazz musician. O True ○ False
Answers
Answer:
True
Explanation:
Carlos Santana
Carlos Santana is a famous american - mexico musician and even a guitarist with some unique music categories like , jazz , Latin , salsa . He started off in late late 1960's with the brand name Santana , which consists of a fusion of rock and roll and even Latin American jazz . And then after his career grows and he became famous .
Hence , the statement is correct .