answer; 1/ 20_2[2-] +2e - ->0.
# of protons
# of neutrons
# of electrons
Atomic Number
Mass Number
18
17
35
17
37
6
8
6
6
15
Answer:
35
Explanation:
is the answer for your question
How did Kepler's discoveries contribute to astronomy?
O They supported the heliocentric model.
O They established the laws of planetary motion.
O They explained how the Sun rises and sets.
O They made astronomy accessible to people who spoke Italian.
They made astronomy accessible to people who spoke italian
Answer:
"They established the laws of planetary motion"
Explanation:
Mr. Kepler was the astronomer who came up with the "Laws of Planetary Motion."
How many moles of iron is equivalent to 4.45 x 10^22 atoms of iron
Answer:
0.074 moles
Explanation:
For every mole (of any element), there are 6.022 x 10^23 atoms.
There are 4.45 x 10^22 atoms of iron.
To find the moles we divide the number of atoms by Avogadro's number
4.45 x 10^22 / 6.022 x 10^23 = 0.0738957
Don't forget sig figs
Answer:
[tex]\boxed {\boxed {\sf 0.0739 \ mol \ Fe}}[/tex]
Explanation:
We are asked to convert a number of iron atoms to moles of iron.
We will use Avogadro's Number for this, which is 6.022 × 10²³. This is the number of particles (atoms, molecules, formula units, etc.) in 1 mole of a substance. For this problem, the particles are atoms of iron. There are 6.022 ×10²³ atoms of iron in 1 mole of iron.
We will also use dimensional analysis to solve this problem. To do this, we use ratios. Set up a ratio using the underlined information.
[tex]\frac {6.022 \times 10^{23} \ atoms \ Fe} {1 \ mol \ Fe}[/tex]
Since we are converting 4.45 × 10²² atoms of iron to moles, we multiply the ratio by that value.
[tex]4.45 \ \times 10^{22} \ atoms \ Fe *\frac {6.022 \times 10^{23} \ atoms \ Fe} {1 \ mol \ Fe}[/tex]
Flip the ratio. The value is the same, but it allows us to cancel the units of atoms of iron.
[tex]4.45 \ \times 10^{22} \ atoms \ Fe *\frac {1 \ mol \ Fe}{6.022 \times 10^{23} \ atoms \ Fe}[/tex]
[tex]4.45 \ \times 10^{22} *\frac {1 \ mol \ Fe}{6.022 \times 10^{23}}[/tex]
Condense into 1 fraction.
[tex]\frac {4.45 \ \times 10^{22} }{6.022 \times 10^{23}} \ mol \ Fe[/tex]
[tex]0.07389571571 \ mol \ Fe[/tex]
The original measurement of atoms ( 4.45 × 10²²) has 3 significaint figures, so our answer must have the same. For the number we calculated, that is the ten-thousandths place. The 9 to the right of this place (0.07389571571) tells us to round the 8 up to a 9.
[tex]0.0739 \ mol \ Fe[/tex]
There are approximately 0.0739 moles of iron in 4.45 × 10²² atoms of iron.
how is the Sun classified?
A as a giant star
B as a medium star
C as a white star as a neutron star
D as a white dwarf
Answer:
As a giant star.
Explanation:
A
Two common methods to generate an aldehyde is by oxidation of an alcohol and through ozonolysis.
a. True
b. False
Answer:
a. True.
Explanation:
Only primary and secondary alcohols can oxidise to give an aldehyde. But a weak oxidizing agent must be used to prevent formation of a carboxylic acid or ketone.
weak oxidizing agents: Chromyl chloride, silver/oxygen/500°C
take an example of ethanol:
[tex]{ \bf{CH _{3} CH_{2}OH \: \: \frac{Ag/O_{2} }{500 \degree C} > \: \:CH _{3} CHO}}[/tex]
[tex]{ \sf{CH _{3} CHO \: \: is \: ethanal}} [/tex]
By ozonolysis:
Here, reactants are Ozone gas, Carbon tetrachloride at a temperature (<20°C), ethanoic acid, zinc and water.
take an example of propanol:
if it undergoes ozonolysis, it gives ethanal and methanal.
Answer:
A. True
Explanation:
Only primary and secondary alcohols can oxidise to give an aldehyde. But a weak oxidizing agent must be used to prevent formation of a carboxylic acid or ketone.
weak oxidizing agents: Chromyl chloride, silver/oxygen/500°C
take an example of ethanol:
By ozonolysis:
Here, reactants are Ozone gas, Carbon tetrachloride at a temperature (<20°C), ethanoic acid, zinc and water.
take an example of propanol:
if it undergoes ozonolysis, it gives ethanal and methanal.
Describe a NAMED example of a non-equilibrium system with respect to it’s energetic nature and equilibrium status.
Answer:
Non-equilibrium thermodynamics is a branch of thermodynamics that deals with physical systems that are not in thermodynamic equilibrium but can be described in terms of variables (non-equilibrium state variables) that represent an extrapolation of the variables used to specify the system in thermodynamic equilibrium.
Explanation:
A wavelength of 489.2 nm is observed in a hydrogen spectrum for a transition that ends in the nf level of the Balmer series. What was ni for the initial level of the electron
Answer:
[tex]n_1=4[/tex]
Explanation:
From the question we are told that:
Wavelength [tex]\lambda=489.2 nm =>4.86*10^{-7}[/tex]
nf level= Balmer series
nf level= 2
Generally the equation for Wavelength is mathematically given by
[tex]\frac{1}{\lambda}=R[\frac{1}{nf^2}-\frac{1}{n_1^2}][/tex]
Where
[tex]R=Rydberg Constant[/tex]
[tex]R=1.097*10^7[/tex]
Therefore
[tex]\frac{1}{4.86*10^{-7}}=1.097*10^7[\frac{1}{2^2}-\frac{1}{n_1^2}][/tex]
[tex]n_1=4.0021[/tex]
[tex]n_1=4[/tex]
For a different reaction, the plot of the reciprocal of concentration versus time in seconds was linear with a slope of 0.056 M-1 s -1 . If the initial concentration was 2.2 M, calculate the concentration after 100 seconds. Show your work.
Answer:
[tex]C_t=0.165M[/tex]
Explanation:
From the question we are told that:
Slope [tex]K=0.056 M-1 s -1[/tex]
initial Concentration [tex]C_1=2.2M[/tex]
Time [tex]t=100[/tex]
Generally the equation for Raw law is mathematically given by
[tex]\frac{1}{C}_t=kt+\frac{1}{C}_0[/tex]
[tex]\frac{1}{C}_t=0.056*100+\frac{1}{2.2}_0[/tex]
[tex]C_t=0.165M[/tex]
The second-order reaction is the reaction that depends on the reactants of the first or the second-order reaction. The concentration after 100 seconds will be 0.165 M.
What is the specific rate constant?The specific rate constant (k) of the second-order reaction is given in L/mol/s or per M per s. It is the proportionality constant that gives the relation between the concentration and the rate of the reaction.
Given,
Slope (k)= 0.056 per M per s
Initial concentration of the reactant [tex](\rm C_{1})[/tex] = 2.2 M
Time (t) = 100 seconds
The concentration of the reaction after 100 seconds can be given by,
[tex]\rm \dfrac{1}{C_{t}} = kt + \dfrac{1}{C_{1}}[/tex]
Substitute values in the above equation:
[tex]\begin{aligned} \rm \dfrac{1}{C_{t}} &= 0.056 \times 100 + \dfrac{1}{2.02}\\\\&= 0.165 \;\rm M\end{aligned}[/tex]
Therefore, after 100 seconds the concentration is 0.165 M.
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what is the bond energy required to break one mole of carbon-carbon bonds
Answer:
100 kcal of bond energy
What does X represent in the following reaction?
239 239
93NP → 94Pu + X
A) a neutron
C) an alpha particle
B) a proton
D) a beta particle
Answer:
D. beta particle
Explanation:
Pu has 94 protons which is only one more than Np (93), that means beta decay. Atomic mass stays the same in beta decay. Beta is very small particle so atomic mass stays at 239.
The given reaction is an example of beta decay where the atomic number of the nuclei increases by one unit and mass number remains unchanged. Therefore, the particle X is a beta particle or an electron.
What is beta decay?Heavy unstable isotopes of atoms undergoes nuclear decay by the emission of charged particles such as alpha or beta particle. In alpha decay, the helium nuclei is emitted and in beta decay, electrons are emitted.
In alpha decay, the mass number of the nuclei decreases by 4 units and atomic number by 2 units. In beta decay, the mass number does not change but the atomic number increases by one unit.
Neptunium undergoes beta decay and forms the plutonium nuclei. Thus X is a beta particle. The reaction is written as follows:
[tex]\rm _{93} ^{239}Np \rightarrow _{94}^{239}Pu + _{-1}^{0}e[/tex]
To find more on beta decay, refer here:
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Which of the following statements is true about what happens in all chemical reactions? A. The ways in which atoms are joined together is not changed. B. Bonds between atoms are broken and new bonds are formed. C. The final substances are called reactants.
Answer:
B.bonds are broken and new bonds are formed
the probability that it will rain tomorrow is 11/15. What is the probability that it will not rain ?
Answer:
4/15
Explanation:
15/15 - 11/15 = 4/15
If 11/15 is the probability that it'll rain tomorrow, then the rest should be the probability that it'll not rain tomorrow.
Which of the following is an example of a physical, rather than a chemical, change?
Answer: The question is not clear
Explanation:
A chunk of a metal alloy displaces 0.58 L of water and has a mass of 2.9 kg. What is the density of the alloy in g/cm3?
Answer:
5g/cm3
Explanation:
firstly convert the litres and kilograms to grams and centimeters.
1l is equivalent to 1000cm3
0.58×1000
580cm3
and 1kg is equivalent to 1000g
2.9×1000
2900
then find the density by using the formula
density=mass/volume
=2900g/580cm3
=5g/cm3
I hope this helps
Which substance will sublimate when in the solid phase at room temperature and pressure?
Select the correct answer below:
A) carbon dioxide
B) water
C) mercury
D) helium
Answer:
I think carbon dioxide is right answer
Which is the electronic configuration for oxygen?
A s'more requires 2 graham cracker squares, 1 marshmallow, and 3 chocolate pieces. If an entire chocolate bar contains 12 chocolate pieces, a marshmallow bag contains 40 marshmallows, and a graham cracker package contains 48 squares, how many s'mores can you make from 8 chocolate bars, one bag of marshmallows, and a package of graham crackers?
Explanation:
try 96 if that's not right let me know and I'll try to fix it
Answer:24
Explanation:
Please help 15 points
What is the change in electrons for nitrogen in the
following reaction?
S + NO3 --> SO2 + NO
Nitrogen gained 4 electrons.
Because Nitrogen's redox number went from +6 to +2, it must have gained 4 electrons (-4) in order to achieve this number. Thus, Nitrogen is reduced.
Identify the true statements regarding hydrogen bonding. Select all that apply. Group of answer choices Hydrogen bonding occurs when a hydrogen atom is covalently bonded to an N, O, or F atom.
Answer:
True
Explanation:
Hydrogen bonding occurs when hydrogen is covalently bonded to a highly electronegative element such as N, O, or F.
Hydrogen bonding affects several physical properties of molecules in which it occur. For example, the high boiling point of water is caused by intermolecular hydrogen bonding irrespective of the low relative molecular mass of water.
The statement stating the presence of hydrogen bonding between the hydrogen and N, O, and F has been true.
Hydrogen bonding has resulted when the electrostatic interaction has been found in the atoms that have been more electronegative than the Hydrogen atoms.
The electrostatic force helps in attracting the atoms towards the hydrogen and thereby the hydrogen bonding takes place. It has been a weak force present in the molecules. The hydrogen bonding can be easily breakable.
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how hydrogen chloride gas is prepared on labrotary by conc sulpheric acid
Answer:
It is prepared small amounts of hydrogen cloride for uses in the lab.
It can be "generated in an HCl generator by dehydrating hydrochloric acid with either sulfuric acid or anhydrous calcium chloride."
Determine the number of hydrogen atoms connected to each carbon atom: The bond-line structure of a compound has a SMILES string of CC1CCN(CC1N(C)C2=NC=NC3=C2C=CN3)C(=O)CC#N. All the carbon atoms of the compound are highlighted and labeled a through p.
Answer:
dsgsdfd
Explanation:
A number is three times the difference between twenty and the number. What is the number?
Answer:
the number is 7
Explanation:
"Three times" means multiply by 3
"Difference" means subtract
"Sum" means add
3(x - 7) = 23 - (3x + 2)
3x - 21 = 23 - 3x - 2
3x - 21 = 21 - 3x
6x = 42
x = 7
A central atom has two lone pairs on opposite sides and four single bonds. What is the molecule geometry of the result?
A. octahedral
B. tetrahedral
C. square planar
D. linear
The correct answer is C. square planar
According to the Valence Shell Electron Pair Repulsion Theory(VSEPR), The shape of a molecule depends on the number of electron pairs in the molecule.
VSEPR theory was first coined by Gillespie and Nyhlom in 1957 as an improvement over the Sidgwick - Powell theory.
According to this theory, the shape of a molecule is determined by the number of electron pairs that surround the valence shell of the central atom in the molecule. The electron pairs are positioned as far apart in space as possible to minimize repulsion of electron pairs.
However, the presence of lone pairs distorts the shape anticipated for the molecule on the basis of VSEPR.
For a molecule having six electron pairs, an octahedral geometry is expected(electron domain geometry). However, the presence of two lone pairs which are positioned at opposite side of the four single bonds leads to an observed square planar molecular geometry.
https://brainly.com/question/13591921
Answer:
square planar
Explanation:
Which of the following is a characteristic of a scientific practice?
a. You have a stock solution of 14.8 M NH3. How many milliliters of this solution should you dilute to make 1000.0 mL of 0.250 M NH3?
b. If you take a 10.0 mL portion of the stock solution and dilute it to a total volume of 0.500 L, what will be the concentration of the final solution?
Answer:A) V = 16.892 ml
Explanation:
M1 * V1 = M2 * V2
14.8 M * V1 =0.250 M * 1000 ml
V1 = 16.892 ml
a. The volume of 16.89 milliliters of the stock solution of 14.8 M should be diluted to make 1000.0 mL of 0.250 M.
b. The concentration of the final solution is 0.296 M.
What is the dilution law?The concentration or the volume of the concentrated or dilute solution can be calculated by using the equation:
M₁V₁ = M₂V₂
where M₁ and V₁ are the concentration and volume of the concentrated solution respectively and M₂ and V₂ are the concentration and volume of the dilute solution.
A stock solution is a solution that has a high concentration and that will be diluted to a low concentration by the addition of water in it.
Given, a stock solution of concentration, M₁ = 14.8 M
The concentration of the diluted solution, M₂ = 0.250 M
The volume of diluted solution, V₂ = 1000ml
Substitute the value of the molarity and volume in equation (1):
(14.8)× (V₁) = (1000) × (0.250)
V₁ = 16.89 ml
Similarly, for part (b): M₁ = 14.8 M, V₁ = 10 ml and V₂ = 0.5L = 500 ml
(14.8)× (10) = (500) × (M₂)
M₂ = 0.296 M
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When hydrogen gas reacts with oxygen gas, water vapour is formed according to the
reaction 2H2 + O2 2H2O. If 3.00 mol of hydrogen gas react with 3.00 mol
of oxygen gas, which reactant will be the reactant in excess?
Explanation:
here's the answer to the question
What are the effects of global warming?
the effects are: temperature rises, water shortages, and increased fire threats
What is the difference between the chemical formula of water and carbon dioxide?
The chemical formula of water is H2O, and the chemical formula of carbon dioxide is CO2. This means that water has 2 atoms of hydrogen and 1 atom of oxygen, which carbon dioxide has 1 atom of carbon and 2 atoms of oxygen. The only similar atom that the two molecules have in common is oxygen. CO2 has one more atom of oxygen than H2O. Hope this helps!
H2O is water. CO2 is CD.
PLEASE HELP!!
this is on USAtestprep
a)
b)
c)
d)
Answer:
B
Explanation:
the fluorine has an high tendency to gain electrons from other elements with lower electronegativities
What is the maximum number of electrons in the following energy level?
n = 4
Answer: 32 electrons
Explanation:
