Answer:
The oxygen atom has lone pairs of electrons.
Explanation:
What element has the following electron configuration:
1s22s22p63s23p2
10. Explain the relationship between the group number and the valence electrons
of MAIN GROUP elements (Groups 1, 2, 13-18). *
Valence electrons are electrons that are in the outermost orbitals of an atom. In the periodic table the elements are divided into groups. All elements of the first main group have one valence electron. All elements of the second main group have two valence electrons. And so on:
group 1 - 1 valence electrongroup 2 - 2 valence electronsgroup 13- 3 valence electronsgroup 14 - 4 valence electronsgroup 15 - 5 valence electronsgroup 16 - 6 valence electronsgroup 17 - 7 valence electronsgroup 18 - 8 valence electronsWas the periodic table of elements created at once by one scientist yes or no
Answer:
Yes
Explanation:
It was Dmitri Mendeleev, a Russian chemist and teacher.
Answer:
No, it wasn't. On Feb.17 in 1869, a very intelligent Russian professor of chemistry, Dimitri Ivanovich Mendeleev created his first part of the periodic table. I hope that helps you.
Explanation:
The purpose of a thermostat on a hot water boiler is:
If you were given a sample of a cotton ball and a glass stirring rod with identical mass (ex: 5.0 g), which sample would contain more oxygen atoms?
Answer:
The sample which would contain more oxygen atoms is a glass stirring rod.
Explanation:
According to the periodic table ,
the glass stirring rod is Silicon dioxide and the cotton ball is cellulose
Here , the molar mass of the glass stirring rod [tex]SiO_{2}[/tex] = 60.08 Grams/mole
Molar mass of the cotton ball [tex]C_{6} H_{10}O_{5}[/tex] = 162.09 gram/mole .
since ,total number of molecules present in oxygen is 32 ,
therefore ,
In glass stirring rod ,
number of oxygen atoms present in 5g = [tex]\frac{32}{60.07} \times 5[/tex]
= 2.66 g of oxygen
[tex]\frac{1}{16} \times 2.66[/tex]
= 0.16625 moles
= 0.16625 x [tex]6.023\times 10^{23}[/tex]
=[tex]1.001 \times10^{23}[/tex] atoms
In cotton ball ,
number of oxygen atoms present in 5g = [tex]\frac{80}{162.09} \times 5[/tex]
= 2.467 g of oxygen
[tex]\frac{1}{16} \times 2.467[/tex]
= 0.15418 moles
= 0.15418 [tex]\times 6.023 \times 10^{23}[/tex]
= 0.928 [tex]\\ \times10^{23}[/tex]
Hence , the glass stirring rod contains more number of oxygen atoms .
For the equation 2KCI + CaF₂ ⇒ 2 KF + CaCI₂, 55.1 mol KCI is reacted with 46.7 mol CaF₂.
1. What is the limiting reactant?
2. How many moles of KF will be produced?
Please Show all your work!! Thank you!
Answer:
Explanation:
Finding Limiting reactant:
Convert all reactant data to moles, divide by respective coefficient => smaller value is the limiting reactant.
Given 2KCl + CaF₂ => 2KF + CaCl₂
55.1mole 46.7mole
(55.1/2) = 27.55 (46.7/1) = 46.7
Limiting reactant is KCl b/c smaller value after dividing by respective coefficients. CaF₂ will be in excess when rxn consumes all KCl.
Moles KF = 55.1 mole as coefficients of two substances in balanced equation are equal.
Answer:
2
Explanation:
How many moles of carbon are produced When 1745g of sugar react according to the equation C6H12O6+ H2SO4 to 6C +6H2O
Answer:
Number of moles of C produced = 58.08 mol
Explanation:
Given data:
Mass of sugar = 1745 g
Moles of C produced = ?
Solution:
Chemical equation:
C₆H₁₂O₆ + 6H₂SO₄ → 6C + 6(H₂SO₄.H₂O)
Number of moles of sugar:
Number of moles = mass/molar mass
Number of moles = 1745 g/180.16 g/mol
Number of moles = 9.68 mol
Now we will compare the moles of C and sugar.
C₆H₁₂O₆ : C
1 : 6
9.68 : 6×9.68 = 58.08 mol
Number of moles of C produced = 58.08 mol
The gas inside a neón light compone or element
Answer:
element
Explanation:
the gas inside a noble gas is made of only one neon atom and is less reactive and would not likely combine with any other element
Each student in a class placed a 2.00 g sample of a mixture of Cu and Al in a beaker and placed the beaker in a fume hood. The students slowly poured 15.0 mL of 15.8 M HNO3 into their beakers. The reaction between the copper in the mixture and the HNO3 is represented by the equation above. The students observed that a brown gas was released from the beakers and that the solutions turned blue, indicating the formation of Cu 2. The solutions were then diluted with distilled water to known volumes. The students determined that the reaction produced 0.010 mol of Cu(NO3)2. Based on the measurement, what was the percent of Cu by mass in the original 2.00 g sample of the mixture
Answer:
Percentage mass of copper in the sample = 32%
Explanation:
Equation of the reaction producing Cu(NO₃) is given below:
Cu(s)+ 4HNO₃(aq) ---> Cu(NO₃)(aq) + 2NO₂(g) + 2H₂O(l)
From the equation of reaction, 1 mole of Cu(NO₃) is produced from 1 mole of copper. Therefore, 0.010 moles of Cu(NO₃) will be produced from 0.010 mole of copper.
Molar mass of copper = 64 g/mol
mass of copper = number of moles * molar mass
mass of copper = 0.01 mol * 64 g/mol = 0.64 g
Percentage by mass of copper in the 2.00 g sample = (0.64/2.00) * 100%
Percentage mass of copper in the sample = 32%
For the reactions below, describe the reactor system and conditions you suggest to maximize the selectivity to make the desired species, D, which is a very small molecule. For full credit, support your suggestions with clear calculations, explanations and sketches where appropriate. Rates are in mol/L.s and concentrations are in mol/L. Reaction 1: A+B D -r1A= 10 exp[-8000 K/T]CACB Reaction 2: B+D U -r2B= 109 exp[-10,000 K/T]CBCD BELOW – make sure to note highlighted question number for answers on Exam Paper. 4. Describe the reactor system and conditions: ___ Answer written on Exam paper AND in BB
Answer:
hello your question lacks the required reaction pairs below are the missing pairs
Reaction system 1 :
A + B ⇒ D [tex]-r_{1A} = 10exp[-8000K/T]C_{A}C_{B}[/tex]
A + B ⇒ U [tex]-r_{2a} = 100exp(-1000K/T)C_{A} ^\frac{1}{2}C_{B} ^\frac{3}{2}[/tex]
Reaction system 2
A + B ⇒ D [tex]-r_{1A} = 10exp( -1000K/T)C_{A}C_{B}[/tex]
B + D ⇒ U [tex]-r_{2B} = 10^9exp(-10000 K/T) C_{B}C_{D}[/tex]
Answer : reaction 1 : description of the reactor system : The desired reaction which is the first reaction possess a higher activation energy and higher temperature is required to kickstart reaction 1
condition to maximize selectivity : To maximize selectivity the concentration of reaction 1 should be higher than that of reaction 2
reaction 2 :
description of reactor system : The desired reaction i.e. reaction 1 has a lower activation energy and lower temperatures is required to kickstart reaction 1
condition to maximize selectivity:
to increase selectivity the concentration of D should be minimal
Explanation:
Reaction system 1 :
A + B ⇒ D [tex]-r_{1A} = 10exp[-8000K/T]C_{A}C_{B}[/tex]
A + B ⇒ U [tex]-r_{2a} = 100exp(-1000K/T)C_{A} ^\frac{1}{2}C_{B} ^\frac{3}{2}[/tex]
the selectivity of D is represented using the relationship below
[tex]S_{DU} = \frac{-r1A}{-r2A}[/tex]
hence SDu = 1/10 * [tex]\frac{exp(-800K/T)}{exp(-1000K/T)} * C_{A} ^{0.5} C_{B} ^{-0.5}[/tex]
description of the reactor system : The desired reaction which is the first reaction possess a higher activation energy and higher temperature is required to kickstart reaction 1
condition to maximize selectivity : To maximize selectivity the concentration of reaction 1 should be higher than that of reaction 2
Reaction system 2
A + B ⇒ D [tex]-r_{1A} = 10exp( -1000K/T)C_{A}C_{B}[/tex]
B + D ⇒ U [tex]-r_{2B} = 10^9exp(-10000 K/T) C_{B}C_{D}[/tex]
selectivity of D
[tex]S_{DU} = \frac{-r1A}{-r2A}[/tex]
hence Sdu = [tex]1/10^7 * \frac{exp(-1000K/T)}{exp(-10000K/T)} *\frac{C_{A} }{C_{D} }[/tex]
description of reactor system : The desired reaction i.e. reaction 1 has a lower activation energy and lower temperatures is required to kickstart reaction 1
condition to maximize selectivity:
to increase selectivity the concentration of D should be minimal
Which example is a trace fossil?
dinosaur footprint
wooly mammoth tusk
insect in amber
dinosaur egges characteristics of a mineral
Answer:
dinosaur footprint
Explanation:
dinosaur footprint because the deffinition of trace fossil is a fossil of a foot print
Answer: Dinosaur footprint should be correct!
Explanation: As in the name, trace footprints are practically just traces, so a Dino print is a perfect example! The dinosaur left a trace, leaving evidence about it, for science to study:) please let me know if this helps! :)
An obligation to do something or control over or care for someone.
Answer: a responsibilty
Explanation:
An obligation to do something or control over or care for someone. The word suitable for it is "responsibility".
An obligation is a duty or responsibility to do anything that is required by law, custom, or moral standards.
Responsibility is an obligation to do something or control over or care for someone. It is a duty or task that one is required to undertake.
Responsibility can be of different forms, such as personal, social, or professional.
Personal responsibility refers to the responsibility that an individual has for their own actions and decisions.
Social responsibility refers to the responsibility that an individual or organization has to act in the best interest of society.
Professional responsibility refers to the responsibility that individuals have to perform their job duties to the best of their ability.
Therefore, the term most suits for the given statement is "responsibility".
Learn more about obligation here:
https://brainly.com/question/32907342
#SPJ4
Which of the following statements is true?
A:Transverse waves move particles parallel to the direction of energy.
B:Longitudinal waves move particles at right angles to the direction of energy.
C:Transverse waves usually occur in solids, while longitudinal waves occur in liquids and gases.
D:All of the above.
Answer:B
Explanation:
For the equation 2H₃PO₄ + 3Ca ⇒ 3H₂ + Ca₃(PO₄)₂ suppose you had 27.4 grams of H₃PO₄?
a. How many grams of Ca would you need to react with this number of moles of H₃PO₄?
b. How many grams of hydrogen gas will be produced?
c. How many moles of calcium phosphate will be produced?
Please answer all questions clearly, with work shown! Thank you!!
Answer:
Explanation:
Given 2H₃PO₄ + 3Ca ⇒ 3H₂ + Ca₃(PO₄)₂
27.4g
=(27.4g/98g/mol)
= 0.280 mole H₃PO₄ used
Ca Used:
Rxn Ratio H₃PO₄ : Ca => 2:3
∴ moles Ca used = 3/2(0.280) mole Ca =0.420 mole Ca
grams Ca used = 0.420 mole Ca x 40 g/mole = 16.8 grams Ca used
Grams H₂ Produced:
Rxn Ratio H₃PO₄ : H₂ => 2:3 => moles H₂ produced = 3/2(0.28 mole H₂) = 0.420 mole H₂ = (0.420 mole H₂ x 2.02 g/mole) = 0.8484 grams H₂(g) Produced.
Moles Ca₃(PO₄)₂ Produced:
FWt Ca₃(PO₄)₂ = 310 g/mole
Rxn Ratio H₃PO₄ : Ca₃(PO₄)₂ => 2:1
∴moles Ca₃(PO₄)₂ Produced = 1/2(moles H₃PO₄ used)
= 1/2(0.28 mole) = 0.14 mole Ca₃(PO₄)₂
If you want grams Ca₃(PO₄)₂, multiply moles Ca₃(PO₄)₂ by formula weight.
Which element has the electron configuration,
1s2 2s2 2p6 3s2 3p3 4s2 3d10 4p6 5s2 4d5 ?
a
manganese
b
technetium
c
rhenium
d
europium
Answer:
B. technetium
Explanation:
10. A sample of an unknown composition was tested in a laboratory. The sample could not be broken down by
physical or chemical means. On the basis of these results, the laboratory reported that the unknown sample was
most likely
A. a compound
B. an element
C. a mixture
Answer:
it would be an element because its an element
Explanation:
Do you agree in the Big Bang theory? Reasoning
The kinetic energy of a golf ball is measured to be 143.3 J. If the golf ball has
a mass of about 47 g, what is its speed?
Answer:
V= in square root 2KE/M=2(143.3J)/0.047kg=6097.8723 in square root around 78.1 approxmete
Kinetic energy is directly proportional to the mass and square of speed of a moving body. Here, the speed of the body of mass 47 g or 0.47 kg with akinetic energy of 143.3 J is 24.6 m/s.
What is kinetic energy?Kinetic energy is a generated by virtue of motion of a body. It is half of the product of mass and square of velocity. Thus as mass is increase kinetic energy also increases.
If velocity is doubled then kinetic energy increases 4 times. Since velocity or speed is in square in the equation written as follows:
KE = 1/2 mv² . Here, m is the mass and v be the speed.
Here, kinetic energy is given 143.3 J and mass of the moving body is 0.47 kg and speed can be calculated by rearranging the equation as follows:
[tex]v = \sqrt{\frac{KE \times 2 }{m } \\\\\\ = \sqrt{\frac{43.3 J \times 2}{0.47 kg} \\\\\\\\\\\\\\ = 24.6 m/s[/tex]
Hence, the speed of the body of mass 47 g or 0.47 kg with akinetic energy of 143.3 J is 24.6 m/s.
To find more about kinetic energy, refer the link below:
https://brainly.com/question/12669551
#SPJ5
Read The Pros and Cons of Plastic to explore some of the useful properties of plastics.
Which properties of plastics allow them to be solutions to many complex problems in the world? Check all that apply.
chemically resistant
durable
non-reactive
high weight
easy to manufacture
Answer:
chemically resistant
durable
non-reactive
easy to manufacture
Explanation:
Plastics are polymer materials which can be moulded or shaped into any desired shape when hot. There are two types of plastics; thermoplastics and thermo sets.
Most plastics are easily manufactured. They are light weight materials , chemically stable, durable and do not undergo chemical reactions upon prolonged exposure to the atmosphere.
The study of chemicals is called chemistry.
The correct answer is options B, C, and E
The plastic is made by the carbon by joining with itself by a covalent bond and this property of carbon is known as catenation.
In today's time plastic is used all over the world and it is because of the following reasons.
Plastic is durable and long lastPlastic is nonreactive and it does not react to anything and remain stable in the free state.Plastic is easy to manufacture because of the high availability of carbon.Hence, the correct answer is B, C, and E.
For more information, refer to the link:-
https://brainly.com/question/25305623
How many electrons are located in the outermost orbit in the Bohr model of a boron atom?
A. 1
B. 2
C. 3
D. 4
According to the electronic configuration of boron, there are three electrons in the Bohr model of a boron atom.
What is electronic configuration?Electronic configuration is defined as the distribution of electrons which are present in an atom or molecule in atomic or molecular orbitals.It describes how each electron moves independently in an orbital.
Knowledge of electronic configuration is necessary for understanding the structure of periodic table.It helps in understanding the chemical properties of elements.
Elements undergo chemical reactions in order to achieve stability. Main group elements obey the octet rule in their electronic configuration while the transition elements follow the 18 electron rule. Noble elements have valence shell complete in ground state and hence are said to be stable.
Learn more about electronic configuration,here:
https://brainly.com/question/13497372
#SPJ2
What atomic symbol completes this reaction?
ГРо
220
Po →
84
?
+
liei
O
224
Pb
82
04
2+
He
2
o
220
At
85
0 220
Rn
86
Answer:
Option C is correct = ₈₅At²²⁰
Explanation:
Given radioactive decay shows the beta emission.
²²⁰₈₄Po ₈₅At²²⁰ + ⁰₋₁e ⁻
Beta radiations are result from the beta decay in which electron is ejected. The neutron inside of the nucleus converted into the proton an thus emit the electron which is called β particle.
Properties of beta radiations:
1) They can travel in air in few meter distance.
2) These radiations can penetrate into the human skin.
3) The mass of beta particle is smaller than the alpha particles.
4) The sheet of aluminium is used to block the beta radiation
¹⁴₆C → ¹⁴₇N + ⁰₋₁e ⁻
The beta radiations are emitted in this reaction. The one electron is ejected and neutron is converted into proton.
Explain the difference between the reactants and
products of a chemical reaction.
3
Answer:
:)
Explanation:
The substance(s) to the left of the arrow in a chemical equation are called reactants. A reactant is a substance that is present at the start of a chemical reaction. The substance(s) to the right of the arrow are called products . A product is a substance that is present at the end of a chemical reaction.
A copper wire is composed of billions of copper units. In this case, the copper in the wire is a(n) __________.
A. atom
B. molecule
C. compound
D. mixture
E. element
Liquid hexane reacts with gaseous oxygen gas to produce gaseous carbon dioxide and gaseous water . What is the theoretical yield of water formed from the reaction of of hexane and of oxygen gas
Answer:
[tex]m_{H_2O}=6.84gH_2O[/tex]
Explanation:
Hello.
In this case, for 5.17 g of hexane (molar mass = 86 g/mol) and 16.5 g of oxygen (molar mass =32 g/mol), we have the reaction:
[tex]C_6H_{14}+\frac{19}{2} O_2\rightarrow 6CO_2+7H_2O[/tex]
Next, via the 1:7 mole ratio of hexane to carbon dioxide and 19/2:7 mole ratio of oxygen to carbon dioxide, we compute the yielded mass of water (molar mass = 18 g/mol) as its theoretical yield by the two masses of reactants and we infer that the limiting reactant is that yielding the fewest moles of product:
[tex]m_{H_2O}^{by\ Hexane}=5.17gC_6H_{12}*\frac{1molC_6H_{12}}{86 gC_6H_{12}} *\frac{7molH_2O}{1molC_6H_{12}}*\frac{18gH_2O}{1molH_2O} =7.57gH_2O\\\\m_{H_2O}^{by\ Oxygen}=16.5gO_2*\frac{1molO_2}{32gO_2} *\frac{7molH_2O}{\frac{19}{2}molO_2 }*\frac{18gH_2O}{1molH_2O} =6.84gH_2O[/tex]
Whereas it is evidenced that oxygen yields the fewest grams of water, therefore, it is the limiting reactant and the theoretical yield of water is:
[tex]m_{H_2O}=6.84gH_2O[/tex]
Best regards!
Do not use cords, and do not plug in many devices into one power source
Aspirin (acetyl salicylic acid) is a weak acid with the chemical formula HC9H7O4. The solubility of aspirin is 4.6 g per 1.00 L solution, and a saturated solution of aspirin has a pH of 2.56. Write the expression (chemical equation) that describes the saturated solution.
Answer:
HC₉H₇O₄(aq) + H₂O(l) ⇄ C₉H₇O₄⁻(aq) + H₃O⁺(aq)
Explanation:
A weak acid as aspirin, HC₉H₇O₄, is in equilibrium with water as follows:
HC₉H₇O₄(aq) + H₂O(l) ⇄ C₉H₇O₄⁻(aq) + H₃O⁺(aq)This is the chemical equation that describes the process.
As you can see, not all aspirin is dissolved, just a part that is converted in its conjugate base (A weak acid doesn't dissociate completely!).
Also, the pH is decreasing because the hydronium ion (H₃O⁺) is produced in the equilibrium (Remember, if you have an increasing in H₃O⁺ concentration the pH will decreases and vice versa).
what are the two main phases of cell division
Answer:
Mitosis meiosis
Explain:
Mitosis is where the cell splits into 2 more cells (diploid)
Meiosis is where the cell splits into 2, and then split again, making 4 (haploid)
When you add milk, sugar and coffee to a cup of hot water, which of these explain that what you formed in a mixture?
A new substances is formed B. You can no longer taste the sugar
C. You can still taste the bittemess of the coffee, the sweetness of the sugar and the creaminess of the milk
D. Each of the part of the mixture changed in color, amount in taste
Answer:
I think it's D. Please let me know if it's wrong or right.
Explanation:
A rectangular metal is 25 dm long, 525 mm wide, and 1.5 m high. This metal weighs 250 lb. Calculate its density in g /mL
Answer:
d = 0.057 g/mL
Explanation:
Given that,
The dimensions of a rectangular metal is 25 dm long, 525 mm wide, and 1.5 m high.
The weight of the metal is 250 lb
We need to find the density of the metal in g/mL.
1 lb = 453.592 g
250 lb = 113398 g
Volume of the block,
V = 25 dm× 525 mm×1.5 m
Since, 1 dm = 0.1 m, 1mm = 0.001 m
V = 2.5 m× 0.525 m× 1.5 m
V = 1.9668 m³
Also, 1 m³ = 1968000 mL
So,
density = mass/volume
density = 113398 g/1968000 mL
= 0.057 g/mL
So, the density of a rectangular metal is 0.057 g/mL.
how many seconds are in 1 year