A student was using the periodic table to organize elements based on their ionization energy from lowest to highest. At the end of the class period, the student left one of the 4 spaces blank.
It looked like this: Ba, Co, ____, He.
Which of the following elements would best fit into this model?
A.
N would go into the blank because it fits the diagonal trend that points towards the upper right.
B.
Se would go into the blank because it fits the diagonal trend that points towards lower left.
C.
Kr would go into the blank because it is a noble gas and has a lower ionization energy than helium but higher than cobalt.
D.
Sb would go into the blank because it has more energy levels than cobalt which gives it a higher ionization energy than cobalt but less than helium.
Answer:
a
Explanation:
because it fits the diagonal trend that point toward the upper right
PLZZZZZ HELPP: How might the fact that multiple approaches yield the same result contribute to the development of a theory? The accumulation of information from multiple approaches provides ample evidence to support the theory. Scientists are more likely to develop a theory for a concept that is a popular area of research. Evidence from multiple approaches might prevent a poorly developed theory from being accepted. The number of observations from multiple approaches usually exceeds the number that is required.
Answer: multiple approaches yield the same result positively contributes to the development of a theory since it shows that the conclusions are sound and not based on other factors such as the environment of the experiment, the researches, etc.
Your welcome . <3Answer:
I'm not positive this is the answer but my guess would be C: Evidence from multiple approaches might prevent a poorly developed theory from being accepted.
Calculate the work (w) and ΔEo, in kJ, at 298 K and 1 atm pressure, for the combustion of one mole of C4H10 (g). First write and balance the equation. The products will be CO2 (g) and H2O (g)
The value of ΔHo for this reaction is -2658.3 kJ/mol
Answer:
Explanation:
2C₄H₁₀ + 13O₂ = 8 CO₂ + 10H₂O
Change in number of moles Δn = 18 - 15 = + 3 moles .
ΔHo = -2658.3 kJ/mol.
ΔHo = ΔEo+ Δn RT
Δn = 3
For one mole Δn = 1.5
ΔHo = ΔEo+ W
W = Δn RT
= 1.5 x 8.31 x 298
= 3714.5 J
= 3.7 kJ /mole
ΔHo = ΔEo+ W
ΔEo = ΔHo - W
= -2658.3 - 3.7 kJ
= - 2662 kJ .
(a) The work done for the combustion of 1 mole of methane is 3,714.5 J.
(b) The change in the energy of the given system is -3,991.2 kJ.
The balanced chemical reaction of the given compounds is written as follows;
[tex]2C_4H_{10} \ + \ 13O_2 \ -->\ 8CO_2 \ + \ 10H_2 O[/tex]
The change in number of moles;
[tex]\Delta n = 18 - 15 = 3[/tex]
The work done for the combustion of 1 mole of methane is calculated as follows;
[tex]W = \frac{\Delta n}{2} RT\\\\W = \frac{3}{2} \times 8.31 \times 298\\\\W = 3,714.6 \ J[/tex]
The energy change is calculated as follows;
[tex]\Delta E_0 = \Delta H_o - W\\\\\Delta E_0 = (\frac{3 \ mole}{2} \times-2658.3 \ kJ/mol) - 3.715 \ kJ\\\\\Delta E_0 = -3,991.2 \ kJ[/tex]
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A story to describe the motion on the graph
A piece of iron is heated to 95.0 celsius and then placed in an insulated vessel containing 250. grams of water at 25.0 celsius. when the system comes to equilibrium the temperature of the system is 35.0 celsius. what is the mass in g of the iron? assume no heat is lost to the surroundingsSpecific heat/J.g^-1 K^-1iron 0.450water 4.184 (A) 4.48 g (B) 41.7 g (C) 387 g (D) 612 g
Answer:
c) 387g
Explanation:
Water;
Mass = 250g
Specific heat = 4.184
Initial Temp, T1 = 25 + 273 = 298K
Final Temp, T2 = 35 + 273 = 308K
Heat = ?
H = mc(T2 - T1)
H = 250 * 4.184 (308 - 298)
H = 10460 J
Iron;
Initial Temp, T2 = 95 + 273 = 368K (Upon converting to kelvin temperature)
Mass = ?
Final Temp, T1 = 35 + 273 = 308
Heat = 10460 (Heat lost by iron is qual to heat gained by water)
Specific heat = 0.45
H = mc(T2-T1)
M = 10460 / [0.45 (308 - 368)]
M = 10460 / 27
M = 387g
The mass of the iron has been calculated as 387.40 grams.
Specific heat can be defined as the amount of heat required to raise the temperature of 1 gram of a substance by 1 degree celsius.
Since in the reaction there has been no heat loss, the heat released by iron has been equivalent to heat absorbed by the water in the calorimeter.
The heat absorbed by calorimeter:Heat = mass × specific heat of water × change in temperature
Heat absorbed = 250 grams × 4.184 J/g[tex]\rm ^\circ C[/tex] × (308 K - 298 K)
Heat absorbed = 10460 J
The heat released by Iron can be given by:
Heat released = mass × specific heat of water × change in temperature
Heat released = mass × 0.45 J/g.K × (308 K - 368 K)
Heat released = mass × 27
Heat released = Heat absorbed
Mass of Iron × 27 = 10460 J
Mass of iron = 387.40 grams.
The mass of the iron has been calculated as 387.40 grams.
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How do the ionic radii vary within a group of metals?
Answer:
ionic radii is a half the distance between two ions
Explanation:
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Kidney stones are caused by the precipitation of either calcium oxalate, Ca(C2O4), or calcium phosphate, Ca3(PO4)2, in the kidneys. If the normal concentration of Ca2+ in the kidneys is 2.5 mM, at what concentration of oxalate ion will kidney stones begin to form?
Answer:
1.1 × 10⁻⁶ M
Explanation:
Step 1: Given and required data
Concentration of Ca²⁺ ([Ca²⁺]): 2.5 mM = 2.5 × 10⁻³ MCalcium oxalate solubility product constant (Ksp): 2.7 × 10⁻⁹Step 2: Write the balanced equation for the solution reaction of calcium oxalate
CaC₂O₄(s) ⇄ Ca²⁺(aq) + C₂O₄²⁻(aq)
Step 3: Calculate the concentration of the oxalate ion to begin the precipitation of calcium oxalate
We will use the Ksp of calcium oxalate.
Ksp = 2.7 × 10⁻⁹ = [Ca²⁺].[C₂O₄²⁻]
[C₂O₄²⁻] = Ksp / [Ca²⁺]
[C₂O₄²⁻] = 2.7 × 10⁻⁹ / 2.5 × 10⁻³
[C₂O₄²⁻] = 1.1 × 10⁻⁶ M
Kidney stones are the calcareous stones formed in the kidney of the excretory system. The initial concentration of oxalate ion was [tex]1.1 \times 10^{-6} \;\rm M.[/tex]
What is concentration?Concentration is the amount of the substance present in the sample and can be calculated by the solubility constant of the products.
Given,
Concentration of calcium = 2.5mM
The solubility product constant = [tex]2.7 \times 10^{-9}[/tex]
The balanced chemical reaction for calcium oxalate can be written as:
[tex]\rm CaC_{2}O_{4}(s) \leftrightharpoons Ca^{2+}(aq) + C_{2}O_{4}^{2-}(aq)[/tex]
The concentration of oxalate ions by Ksp is calculated as:
[tex]\begin{aligned} [C_{2}O_{4}^{2-}] &= \rm \dfrac {Ksp}{[Ca^{2+}]}\\\\&= \dfrac{2.7 \times 10^{-9}}{2.5 \times 10^{-3}}\\\\&= 1.1 \times 10^{-6}\;\rm M\end{aligned}[/tex]
Therefore, [tex]1.1 \times 10^{-6} \;\rm M[/tex] is the concentration of oxalate ion.
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Which of the following best describes how atoms bond in a copper sample?
O the atoms either gain or lose electrons to meet the octet rule.
O positively charges ions are spread apart throughout the entire molecule
the atoms all gain electrons to form anions in order to remain unstable
the atoms share electrons in order to achieve a stable octet
Answer:
The first option is the correct option
Explanation:
Copper is one of the transition elements which are normally found in the d-block. Generally, transition elements that have low oxidation number/charge usually undergo ionic/electrovalent bonding, while those that have a relatively higher oxidation number/charge usually undergo covalent bonding. Copper has charges ranging from 1+, 2+ or 3+ and thus will normally undergo ionic bonding which involves the gain or loss of electrons to meet the octet rule.
The best description of how atoms bond in a copper sample is; the atoms share electrons in order to achieve a stable octet - a type of bonding called Metallic bonding.
According to the question;
We are required to identify which of the following best describes how atoms bond in a copper sample.Definition:
A metallic bond is pretty different from covalent and ionic bonds, but the objective of the bonding is the same: to achieve a lower energy state.
Contrary to a bond between just two atoms, a metallic bond is a sharing of electrons between many atoms of a metal element.
P.S: Copper is one of the transition metals with variable oxidation states.
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Any science fair project ideas? Something for 7th or 8th grade level.
Answer:
maybe try to do something with electricity?
Explanation:
give me an update on when u find one :) cant wait to see it
Within which of Linnaeus's groupings are organisms most closely related to one another?
A) species
B) genus
C) phylum
D) kingdom
Answer:
B)Explanation:
A genus is a group that includes a number of very closely related species; a species within a genus includes populations of organisms that can potentially interbreed.
Could someone draw me electron dot diagrams? The Hydride Ion, Hydrogen Ion, Aluminum Ion, Nitride Ion, Oxide Ion, and Calcium Ion, and Sodium-Ion dot structures? Thanks!
Answer:
urorrr
Explanation:
hahhahahahahhaahah oki nam omy mymy mymy
HELPP ANSWERSSS!!!!
Which of the following elements in Group 13 would most likely have a physical and chemical properties of brittle, shiny, semiconductor, and is silver?
A.
Indium
B.
Gallium
C.
Aluminum
D.
Boron
Answer:
answer is
Explanation:
Gallium because it has the properties which you have mentioned
The element of Group 13 would most likely have a physical and chemical properties of brittle, shiny, semiconductor, and is silver is gallium. The correct option is B.
What is gallium?Gallium is a chemical substance with the atomic number 31 and indeed the emblem Ga.
Gallium belongs to periodic table group 13 and is chemically similar to the other metals in the group. In standard temperature and pressure, gallium is a soft, silvery metal.
It finds widespread application in Blu-ray technology, mobile phones, blue and green LEDs, and pressure sensors for touch switches. Gallium readily alloys with the majority of metals.
It is especially useful in low-melting alloys. Because of its high boiling point, it is ideal for recording temperatures that would vaporize a thermometer.
Gallium is a rare element on Earth, but its abundance is comparable to that of lithium and lead, with a content of 19 ppm in the continental crust.
Thus, the correct option is B.
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What is the concentration (M) of a NaCl solution prepared by dissolving 9.1 g of NaCl in sufficient water to give 375 mL of solution?
Answer:
d
Explanation:
What is the pressure in atmospheres exerted by a column of water that is 12.5 m
high?
(density of water = 1.00g/cm3; gravitational constant = 9.80665 m/s2, 1 atm =
101,325 Pa = 760 torr = 760 mmHg)
Answer:
0.00121 atm
Explanation:
Step 1: Given data
Height of the column of water (h): 12.5 mDensity of water (ρ): 1.00g/cm³Gravitational constant (g): 9.80665 m/s²Step 2: Calculate the pressure exerted by the column of water in SI units
The pressure exerted by the column of liquid depends on the height of the column, the density of the liquid and the gravitational constant. We can calculate it using the following expression.
P = ρ × g × h
P = 1.00g/cm³ × 9.80665 m/s² × 12.5 m
P = 123 Pa
Step 3: Convert "P" to atm
We will use the conversion factor 101325 Pa = 1 atm.
123 Pa × (1 atm/101325 Pa) = 0.00121 atm
Name a substance/solution that could be used to distinguish alkane from an alkene.
Answer: Bromine water
Explanation:
Alkanes are saturated hydrocarbons with single bond and the alkenes as unsaturated hydrocarbons with double bonds.
Bromine water is a chemical reagent which is used to distinguish between alkane and alkene.
It is of orange color in solution form and turns to colorless in alkene.
The alkanes to show any reaction with bromine water.
What is the name of the product that forms when sodium hydroxide reacts with propanoic acid is?
Answer:
Propionic acid reacts with NaOH(aq) to form sodium propionate and water.
Explanation:
.
PLEASE HURRY
Which input value produces the same output value for the two functions on the graph. f(x) = - x+
g(x) = ģx-2
.
x= -3
x= -1
X = 1
x= 3
Answer:
3
Explanation:
Your problem statement tells you .... f(x) passes through point (3, negative 1) g(x) passes through point (3, negative 1) This tells you the input value that produces the same output value for the two functions is 3, and that output value is -1.
Which statement describes effusion?
A) It occurs when a gas passes through a tiny hole.
B) It occurs when a liquid passes through a tiny hole.
C) It occurs when gas molecules disperse throughout a container.
D) It occurs when a liquid disperses throughout a container.
Answer:
choice A
Explanation:
it it occurs when a gas escapes from a container through a hole of diameter.
Answer:
A. It occurs when a gas passes through a tiny hole.
Explanation:
Edge2020
Have a great day y'all :)
choose all the pairs of elements that will form a compound with an covalent/molecular bond
a. phosphorus and iodine
b. rubidium and fluorine
c. sulfur and chlorine
d. aluminum and bromine
Answer:
B
Explanation:
100,000 years in the geologic history of Earth would be considered
Answer:
". It will mark the time since humans began altering Earth. Starting about 10,000 years ago, it is tentatively being called the Anthropocene."
i dont know if tht will help
100,000 years in the geologic history of Earth would be considered
as Anthropocene .
What is Anthropocene?
The first and most recent geological epoch in Earth's history when human life began to have a noticeable influence on the planet's climate, including ecosystems, and ecosystems, is referred to as the Anthropocene Epoch. This term refers to an undefined unit of geologic time.
It would be the first time since people started changing the planet. It must be tentatively referred to as the Anthropocene and began around 10,000 years ago.
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What is the wavelength of a photon with an energy of 3.50 x 10^-19 J ?
Answer:
λ = 5.68×10⁻⁷ m
Explanation:
Given data:
Energy of photon = 3.50 ×10⁻¹⁹ J
Wavelength of photon = ?
Solution:
E = hc/λ
h = planck's constant = 6.63×10⁻³⁴ Js
c = 3×10⁸ m/s
Now we will put the values in formula.
3.50 ×10⁻¹⁹ J = 6.63×10⁻³⁴ Js × 3×10⁸ m/s/ λ
λ = 6.63×10⁻³⁴ Js × 3×10⁸ m/s / 3.50 ×10⁻¹⁹ J
λ = 19.89×10⁻²⁶ J.m / 3.50 ×10⁻¹⁹ J
λ = 5.68×10⁻⁷ m
What is the formula for hydrophosphoric acid?
Answer:
H3PO4 is the formula for hydrophosphoric acid
The chemical formula of hydrophosphoric acid is H₃PO₄ which is a mineral acid of phosphorous.
What is chemical formula?Chemical formula is a way of representing the number of atoms present in a compound or molecule.It is written with the help of symbols of elements. It also makes use of brackets and subscripts.
Subscripts are used to denote number of atoms of each element and brackets indicate presence of group of atoms. Chemical formula does not contain words. Chemical formula in the simplest form is called empirical formula.
It is not the same as structural formula and does not have any information regarding structure.It does not provide any information regarding structure of molecule as obtained in structural formula.
There are four types of chemical formula:
1)empirical formula
2) structural formula
3)condensed formula
4)molecular formula
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Who was the creator of the atomic bomb and why was he against the project?
Answer:Robert Oppenheimer went on to become chairman of the General Advisory Committee of the Atomic Energy Commission, which, in October 1949, opposed the development of the hydrogen bomb. This shocking opposition led to accusations that Oppenheimer was a Communist supporter.
Explanation:
Please answer this question
Answer:
I'm not an expert at this, but I assume its mercury.
How many molecules are contained 9.6 mol C2H4?
Answer:
N = 5.8 × 10²⁴ molecules
Explanation:
Step 1: Given and required data
Moles of C₂H₄ (n): 9.6 molAvogadro's number (NA): 6.02 × 10²³ molecules/molStep 2: Calculate the number of molecules (N) in 9.6 moles of C₂H₄
To convert moles to molecules we need Avogadro's number: there are 6.02 × 10²³ molecules of C₂H₄ per mole of C₂H₄
N = n × NA
N = 9.6 mol × 6.02 × 10²³ molecules/mol
N = 5.8 × 10²⁴ molecules
I have a buddy who recycles electronics, and isolates metals from the connector pins electrical boards. He isolates gold, for example, and purifies it the best he can, then sells it along with his other scrap metal. This last go around he was able to isolate 3.00 g of Au with a process he claims results in a 80.0% yield. If he is correct, what is his theoretical yield? In other words, he got 3.00 g, but what should he have been able to get?
Solution :
In the process to isolate gold that has a 80 percent yield, a 3.00 g of Au is being isolated.
That is, the actual yield of Au is 3. 00 g
Therefore, we need to find the theoretical yield.
As we know,
[tex]$\text{percent yield}=\frac{\text{actual yield}}{\text{theoretical yield}} \times 100$[/tex]
[tex]$\text{theoretical yield}=\frac{\text{actual yield}}{\text{present yield}} \times 100$[/tex]
As actual yield = 3.00 g
percent yield = 80 %
So, theoretical yield = [tex]$\frac{3.00}{80} \times 100$[/tex]
= 3.75 g
Thus he should be able to get 3.75 g which is the theoretical yield of Au.
Question 20
Review
Which solution is the most concentrated?
1. 1 mole of solute dissolved in 1 liter of solution
2. 2 moles of solute dissolved in 3 liters of solution
3. 6 moles of solute dissolved in 4 liters of solution
4. 4 moles of solute dissolved in 8 liters of solution
Please help me it’s due today at 7:40pm please please help me please people please
Answer:
action, reaction
Explanation:
Answer:
for every action there is an equal and opposite reaction
Which of the following would lose heat the fastest?
15 grams of water
200 grams of water
1000 grams of water
500 grams of water
Answer:
15 grams of water
Explanation:
15 grams of water of water would lose heat the faster compared to higher masses of water.
Water generally is a poor conductor heat.
To heat up a unit of water, significant amount of energy must be added to the body of water. With time, the body continues to increase in temperature. A 500g mass of water will take more time to lose heat.A 31.4 mL sample of nitrogen gas was collected over water at 23.7°C and a total pressure of 706 torr. What mass of nitrogen gas was collected
Answer:
[tex]m=0.0325g[/tex]
Explanation:
Hello!
In this case, since the collection of gases over at certain conditions implies the usage of the ideal gas equation and computation of the pressure of the gas by subtracting the vapor pressure of water (21.7 torr at 23.7 °C) to the total pressure as shown below:
[tex]p_N=706-21.7=684.3torr =0.900atm[/tex]
Next step is to compute the moles of nitrogen at the given conditions:
[tex]n=\frac{PV}{RT}=\frac{0.900atm*0.0314L}{0.08206\frac{atm*L}{mol*K}*296.85K} \\\\n=0.00116mol[/tex]
Final step is to compute the mass by knowing that gaseous nitrogen has a molar mass of 28.02 g/mol:
[tex]m=0.00116mol*\frac{28.02g}{1mol} \\\\m=0.0325g[/tex]
Regards!
The mass of nitrogen gas that was collected is 0.0336 grams.
Given the following data:
Volume of nitrogen gas = 31.4 mLTemperature = 23.7°C to K = 296.7 KelvinPressure = 706 torr to atm = 0.93 atm.Scientific data:
Ideal gas constant, R = 0.0821 L⋅atm/mol⋅KMolar mass of nitrogen gas = 28.02 g/molTo determine the mass of nitrogen gas that was collected:
First of all, we would calculate the number of moles of nitrogen gas used by using the ideal gas law equation:
[tex]n = \frac{PV}{RT}[/tex]
Where;
P is the pressure. V is the volume. n is the number of moles of gas. R is the ideal gas constant. T is the temperature.Substituting the given parameters into the formula, we have;
[tex]n = \frac{0.93 \times 0.0314}{0.0821 \times 296.7}\\\\n=\frac{0.0292}{24.36}[/tex]
n = 0.001199 moles
For the mass of nitrogen gas:
[tex]Mass = n \times molar \;mass\\\\Mass = 0.001199 \times 28.02[/tex]
Mass = 0.0336 grams
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