A group of students are wandering around a room. When their teacher claps, the students sit down wherever they are. This situation best models the formation of which type of solid? an amorphous solid because the particles do not have a regular structure an amorphous solid because the motion of the particles stopped a crystalline solid because the moving particles lock into fixed positions a crystalline solid because the particles have a long-range order
Answer:
A. just took the test!!!
Explanation:
According to the forces of attraction, the situation best models the formation amorphous solid because the particles do not have a regular structure.
What are forces of attraction?Forces of attraction is a force by which atoms in a molecule combine. it is basically an attractive force in nature. It can act between an ion and an atom as well.It varies for different states of matter that is solids, liquids and gases.
The forces of attraction are maximum in solids as the molecules present in solid are tightly held while it is minimum in gases as the molecules are far apart . The forces of attraction in liquids is intermediate of solids and gases.
The physical properties such as melting point, boiling point, density are all dependent on forces of attraction which exists in the substances.
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A 5.687 g sample of iron reacts with oxygen, forming an iron oxide. The final mass of the iron oxide is 8.131 g. What is the formula of the iron oxide
Answer:
Fe₂O₃
Explanation:
Mass of Iron = 5.687 g
Mass of Iron oxide = 8.131 g
Mass of Oxide = Mass of Iron oxide - Mass of Iron
Mass of oxide = 8.131 - 5.687 = 2.444 g
Moles of Iron = Mass / Molar mass = 5.687 / 55.845 = 0.1018 moles
Moles of Oxide = Mass / Molar mass = 2.444 / 16 = 0.15275 moles
To determine the formular, we have to find the smallest whole number ration that exists between the elements.
To do that, we divide by the smallest number;
Iron = 0.1018 / 0.15275 = 0.6664 = 2/3 (Approximately)
Oxygen = 0.15275 / 0.15275 = 1
To get the smallest whole number ratio, multiply all through by 3.
Iron = 2/3 * 3 = 2
Oxygen = 1 * 3 = 3
The formular will be;
Fe₂O₃
What are the three methods of transportation in Protists?
Answer:
All protists can travel through water by one of three methods: cilia, flagella, or pseudo/axopodia. With that said, let's explore the three main types of protists and their forms of locomotion.
Explanation: Have a great rest of your day :)
What’s the answer for this question which i have posted can I know the answers as possible
The change in internal energy = 2.701 x 10² kJ
Further explanationGiven
Heat absorbed by system = 1.69 x 10² kJ
Work done on system = 1.011 x 10² kJ
Required
The change in Internal energy
Solution
We can use the first law of Thermodynamics :
[tex]\tt \Delta U=Q+W[/tex]
The sign rules for heat and work are set as follows:
• The system receives heat, Q +
• The system releases heat, Q -
• The system does work, W -
• the system accepts work, W +
Heat absorbed/receive heat from surrounding = Q+
Work done on the system = W+
and input the given values
[tex]\tt \Delta U= 1.69\times 10^2+1.011\times 10^2\\\\\Delta U=\boxed{\bold{2.701\times 10^2~kJ}}[/tex]
What is the name of a solid product that settles out of an aqueous solution as a result of a reaction between aqueous
reactants?
A buffer that contains 0.578 M base, B, and 0.263 M of its conjugate acid, BH , has a pH of 8.97. What is the pH after 0.0020 mol of HCl is added to 0.250 L of this solution?
Answer:
pH = 8.95
Explanation:
A buffer follows H-H equation:
pH = pKa + log [B] / [BH⁺]
Where pH is pH of the buffer: 8.97
pKa is a constant of the buffer (Our incognite)
[B] is molar concentration -or moles- of the base: 0.578M
[BH⁺] is molar concentration -or moles- of conjugate acid: 0.263M
pH = pKa + log [B] / [BH⁺]
8.97 = pKa + log [0.578M] / [0.263M]
8.628 = pKa of the buffer
0.250L contains:
[B] = 0.578M * 0.250L = 0.1445 moles of B
[BH⁺] = 0.263M * 0.250L = 0.06575 moles of BH⁺
When HCl is added, B is consumed and BH⁺ is produced as follows:
HCl + B → BH⁺ + Cl⁻
That means moles of each species after the addition of HCl is:
[B] = 0.1445 moles - 0.0020moles = 0.1425moles
[BH⁺] = 0.06575 moles + 0.0020moles = 0.06775moles
Replacing in H-H equation, pH is:
pH = 8.628 + log [0.1425moles] / [0.06775moles]
pH = 8.95
25 Points!!! Which ion has the larger ionic radius: Ca 2+ or Cl -?
I am very confused on this topic so please give me the best explanation possible instead of just giving me the answer. I am giving 25 points for a reason thank you!!!
Answer:
Cl- is has the larger ionic radius
Explanation:
When all atoms/ions are in the same noble gas configuration, then you would just compare the ratio of protons to electrons. Whichever has the highest proton/electron ratio would have the smallest nucleus. Therefore Ca2+ has the smallest nucleus while Cl- has the largest nucleus
During a chemical reaction, some atoms can change into other atoms.
A. Never
B. Always
C.Sometimes
Answer:
C.
Explanation:
:)
Which element is in Group 2 and Period 7 of the Periodic Table?
A)
radium
B)
manganese
c)
magnesium
D)
Radon
Answer:
A) Radium
i don't think that group 2 has period 7, it has only up to period 6 so it's probably Radium :))
The statement of the element is in Group 2 and Period 7 of the Periodic Table is "Radium."
What is group and period?The vertical columns of the periodic table are referred to as 'groups,' whereas the horizontal rows are referred to as 'periods.' Members of the same group in the table have the same number of electrons in their atoms' outermost shells and form similar bonds.
Alkaline earth metals are found in Group 2 of the periodic chart. The elements beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), and radium (Ra) are all found in Group 2 of the periodic table (Ra). By referring the periodic table chart, radium is an element that positioned in the group 2 and period 7.
Hence the correct option is A.
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How much heat, in joules, must be added to a 75.0-g iron block with a specific heat of 0.449 J/g °C to increase its temperature from 25 °C to its melting temperature of 1535 °C?
Answer:
50,849.25 Joules
Explanation:
The amount of heat, Q, required to raise the temperature of a body with mass, m, and specific heat capacity, c is given by:
Q = mcΔT, where ΔT represents the change in temperature.
In the case of the iron block:
m = 75 g
c = 0.449 J/g °C
ΔT = 1535 - 25 = 1510 °C
Therefore,
Q = 75 g x 0.449 J/g °C x 1510 °C
= 50,849.25 Joules
Hence, 50,849.25 Joules of heat must be added to a 75.0-g iron block with a specific heat of 0.449 J/g °C to increase its temperature from 25 °C to its melting temperature of 1535 °C
How many atoms of hydrogen are there in HCOOH2?
Answer:
2
Explanation:
g00gle
I'm not that smart :)
When a child slides down a slide (if there is no friction and all of the mechanical energy is conserved) what would happen?
Question 3 options:
A. Potential energy would turn to Kinetic energy
B. The energy is destroyed
C. Kinetic energy would turn in to Potential energy
D. All energy stays the same
the answer is C: Kinetic energy would turn into Potential energy.
The electronic configuration of Na is_________.
An automobile engine provides 631 Joules of work to push the pistons.In this process the internal energy changes by -2881 Joules.Calculate q for the engine. This represents the amount of heat that must be carried away by the cooling system.
Answer:
q = - 2250 Joules
Explanation:
work, w = 631 joules
internal energy ΔU = -2881 joules
q = ?
The relationship between work, internal energy and q is given by the equation;
q + w = ΔU
Since work is done by the automobile energy, it would have a negative sign, hence;
ΔU = q - w
Inserting the values and solving for q;
ΔU + w = q
q = -2881 + 631
q = - 2250 Joules
How long (in hours) will a current of 2.00 A need to be applied to produce 50.0 grams of aluminum metal from molten Al2O3
Answer:
[tex]t=74.5hr[/tex]
Explanation:
Hello!
In this case, given the mass of aluminum metal which can undergo the following reduction from aluminum oxide:
[tex]Al^{3+}+3e^-\rightarrow Al[/tex]
We can see three moles of electrons are transferred per mole of aluminum, thus, we obtain:
[tex]mole^-=50.0gAl*\frac{1molAl}{26.98gAl}*\frac{3mole^-}{1molAl} =5.56mole^-[/tex]
Next, we compute the charge carried by those electrons via the faraday's constant:
[tex]q=5.56mole^-*\frac{96,485C}{1mole^-} =536,425C[/tex]
Finally, considering the applied current, we compute the elapsed time in hours to achieve such electrolysis:
[tex]t=536,425C*\frac{s}{2.00C} *\frac{1hr}{3600s} \\\\t=74.5hr[/tex]
Best regards!
What’s the answer to my problem ?
Answer:
b
Explanation:
Which of the following would always combine and form a covalent bond?
A C and I
B Na and I
C K and O
D Ba and S
Answer
D or A
Explanation:
Answer:
Nonmetal atoms frequently form covalent bonds with other nonmetal atoms. For example, the hydrogen molecule, H2, contains a covalent bond between its two hydrogen atoms. Figure 1 illustrates why this bond is formed. Starting on the far right, we have two separate hydrogen atoms with a particular potential energy, indicated by the red line. Along the x-axis is the distance between the two atoms. As the two atoms approach each other (moving left along the x-axis), their valence orbitals (1s) begin to overlap. The single electrons on each hydrogen atom then interact with both atomic nuclei, occupying the space around both atoms. The strong attraction of each shared electron to both nuclei stabilizes the system, and the potential energy decreases as the bond distance decreases. If the atoms continue to approach each other, the positive charges in the two nuclei begin to repel each other, and the potential energy increases. The bond length is determined by the distance at which the lowest potential energy is achieved.
Explanation:
In ionic compounds, electrons are transferred between atoms of different elements to form ions. But this is not the only way that compounds can be formed. Atoms can also make chemical bonds by sharing electrons equally between each other. Such bonds are called covalent bonds. Covalent bonds are formed between two atoms when both have similar tendencies to attract electrons to themselves (i.e., when both atoms have identical or fairly similar ionization energies and electron affinities). For example, two hydrogen atoms bond covalently to form an H2 molecule; each hydrogen atom in the H2 molecule has two electrons stabilizing it, giving each atom the same number of valence electrons as the noble gas He.Compounds that contain covalent bonds exhibit different physical properties than ionic compounds. Because the attraction between molecules, which are electrically neutral, is weaker than that between electrically charged ions, covalent compounds generally have much lower melting and boiling points than ionic compounds. In fact, many covalent compounds are liquids or gases at room temperature, and, in their solid states, they are typically much softer than ionic solids. Furthermore, whereas ionic compounds are good conductors of electricity when dissolved in water, most covalent compounds are insoluble in water; since they are electrically neutral, they are poor conductors of electricity in any state.
one mole of H2 S o4 contains off 4.22 into 10 raise to power 24 atoms is it true or false
Answer:
False. One mole of a certain substance will always contain [tex]6.002 \cdot 10^{23}[/tex] atoms of that substance.
Explanation:
Hope this helped!
it contains the number of avogadro of moles which is 6.022*10^23 ,not4,22*10^24 therefore it's false
You need to make an aqueous solution of 0.187 M nickel(II) iodide for an experiment in lab, using a 300 mL volumetric flask. How much solid nickel(II) iodide should you add?
Answer:
17.53 g
Explanation:
The chemical formula of nickel (II) iodide is NiI₂. Its molar mass (MM) can be calculated from the molar mass of its chemical elements:
MM(NiI₂) = 58.7 g/mol + (2 x 126.9 g/mol)= 312.5 g/mol
Given the following data:
M = 0.187 M = 0.187 mol/L
V= 300 mL = 0.3 L
We calculate the mass of NiI₂ as the product of the molarity of the solution (M), the molar mass (MM) and the volume:
mass = M x MM x V = (312.5 g/mol) x (0.187 mol/L) x 0.3 L = 17.53 g
Therefore, we have to add 17.53 grams of solid nickel(II) iodideto prepare the solution.
How many electrons will an iodine atom donate or accept, based on its number of valence electrons
Answer:
Iodine has seven valence electrons.
Explanation:
Valence electrons of an atom are located in the outermost shell of the atom and participate in bonding.
if 8 g of ammonium hydroxide is completely decomposed by the reaction below in a closed container with a total volume of 5.oo L and at 25 degrees C, what will be the partial pressure of the amonia gas liberated, in atmospheres? Assume the volume of the liquid is negligible.
NH4OH(aq)=H2O(1)+NH3(g)
Answer:
1 atm
Explanation:
Step 1: Write the balanced equation
NH₄OH(aq) ⇒ H₂O(l) + NH₃(g)
Step 2: Calculate the moles corresponding to 8 g of NH₄OH
The molar mass of NH₄OH is 35.04 g/mol.
8 g × 1 mol/35.04 g = 0.2 mol
Step 3: Calculate the moles of NH₃ formed from 0.2 moles of NH₄OH
The molar ratio of NH₄OH to NH₃ is 1:1. The moles of NH₃ formed are 1/1 × 0.2 mol = 0.2 mol
Step 4: Calculate the pressure of 0.2 moles of NH₃ in a container of 5.00 L at 25 °C (298 K)
We will use the ideal gas equation.
P × V = n × R × T
P = n × R × T / V
P = 0.2 mol × 0.0821 atm.L/mol.K × 298 K / 5.00 L
P = 1 atm
decomposition of hydrogen peroxide produce water and oxygen . calculate the volume of O2 formed from the decomposition of 150 mL of 0.02M hydrogen peroxide at stp
Explanation:
2H2O2 => 2H2O + O2
Moles of hydrogen peroxide = 0.150dm³ * (0.02mol/dm³) = 0.003mol .
Moles of oxygen = 0.0015mol.
Volume of oxygen = 0.0015mol * (22.4dm³/mol) = 0.0336dm³.
All members of the alkene series of hydrocarbons have the general formula:
Select one:
a. CnH2n-2
b. CnH2n+2
C. CnHn
d. CnH2n
Answer:
D: CnH2n
Explanation:
Unsaturated hydrocarbons have double and/or triple bonds between carbon atoms. Those with double bond assuming they have non-cyclic structures are called alkenes with the general formula C_nH_2n. Meanwhile the hydrocarbons that possess triple bonds are called alkynes and possess the general formula CnH2n-2.
Looking at the options, for alkenes, the correct answer is option D
5. Base your answer to the question on the particle diagrams
below, which show atoms and/or molecules in three different
samples of matter at STP.
Key
atom of x
atom of y
O atom of z
30
Sample 1 Sample 2 Sample 3
Which sample represents a pure substance?
1. Sample 1
2. Sample 2
3. Sample 3
Answer:sample 3
Explanation:because if only have one kind of substance which makes it pure
what element has 4 energy levels and 1 valence electron
Answer: Hydrogen and helium, both in the first period, have their valence electrons in the principal energy level n=1.
Hope this helps.......... Stay safe and have a Merry Christmas!!!!!!!!!! :D
Explanation:
Hydrogen has 4 energy levels and 1 valence electron according to its electronic configuration.
What is an energy level?Electrons present in an atom revolve in different orbits which are stationary states and are also called as energy levels. The energy levels are numbered as integers which are also called as principal quantum numbers.
Energy of the stationary state is given as E= -R
1/n² where R
is the Rydberg's constant. When an electron is excited, and it moves from lower to higher energy levels there is absorption of energy, while when it moves from higher energy level to lower energy level it radiates or gives out energy in the form of radiation.
They can also be defined as the distances between electron and nucleus of an atom . Electrons present in K energy level have least energy .Energy level diagrams are studied to understand nature of bonding , placement of electrons in orbits and and elemental behavior under certain conditions.
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Platinum crystallizes with the face-centered cubic unit cell. The radius of a platinum atom is 139 pm. Calculate the edge length of the unit cell and the density of platinum in g>cm3.
Answer:
Length = 393pm, Density = 21.3 g/cm^3.
Explanation:
From the question above, we have the following parameters or data which is going to aid in solving the above Question.
=> The radius of a platinum atom = 139 pm.
Therefore, the length can be calculated by making use of the formula given below:
Length = 2 √( 2r) = 2 × √ (2 × 139 × 10^-12m ) = 393 × 10^-10 m = 393pm.
The density can be calculated by making use of the chemical formula given below:
Density = mass ÷ volume = (195.064/ 6.02 × 10^23) ÷ (3.93 × 10^-10/ 10^-2) = 21.3 g/cm^3.
Length = 393pm, Density = 21.3 g/cm^3.
The calculation is as follows:Length = 2 √( 2r) = 2 × √ (2 × 139 × 10^-12m )
= 393 × 10^-10 m
= 393pm.
Now
The density should be
We know that
Density = mass ÷ volume
= (195.064/ 6.02 × 10^23) ÷ (3.93 × 10^-10/ 10^-2)
= 21.3 g/cm^3.
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When a lead storage battery discharges, the concentration of ___.
Lead sulfate in the battery decreases
Sulfuric acid increases
Sulfuric acid decreases
Lead sulfate in the battery remains constant
Answer:
Sulfuric acid decreases
Based on the chart below, which of the tests measured physical properties?
(sorry I don't know how to attach images but here are the choices- choose one only)
-density, reaction to flame
-density, phase
-reaction to flame and water
-phase, reaction to water
Sodium will react with ozone (O3) at high temperatures to yield sodium oxide, and no other products. How many atoms of sodium will react completely with 40 molecules of O3
Answer:
The correct answer is 240 atoms Na
Explanation:
According to the given scenario, the calculation of the number of sodium atoms reacted is as follows:
As we know that
The sodium reaction with [tex]O_3[/tex]
[tex]6Na + O_3 \overset{\Delta} \rightarrow} 3Na_2O \mhchem[/tex]
1 mole of [tex]O_3[/tex] reacted with the 6 moles Na attom
1 molecule [tex]O_3[/tex] [tex]\rightarrow[/tex] 6 atoms Na
40 molecule [tex]O_3 \rightarrow[/tex] 6 × 40 = 240 atoms Na
hence, the number of sodium atoms reacted is 240 atoms Na
Atoms of sodium will react completely with 40 molecules of O₃ is 240.
What is stoichiometry?Stoichiometry of any chemical reaction tells about the relative amount of entities present in that reaction, before and after.
Given chemical reaction will be represent as:
6Na + O₃ → 3Na₂O
From the stoichiometry of the reaction it is clear that:
1 molecule of ozone = react with 6 atoms of sodium
So, 40 molecule of ozone = react with 40×6=240 atoms of sodium
Hence, required atoms of sodium is 240.
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Humans have three types of cone cells in their eyes, which are responsible for color vision. Each type absorbs a certain part of the visible spectrum. Suppose a particular cone cell absorbs light with a wavelength of 549.nm. Calculate the frequency of this light. Be sure your answer has the correct number of significant digits.
Answer:
5.46 x 10¹⁴ Hz
Explanation:
The relation between frecuency (ν) and wavelength (λ) is given by:
c = λν
Where c is the speed of light and it is constant: 2.998 x 10⁸ m/s.
Given: λ = 549 nm x 10⁻⁹ m/1 nm = 5.49 x 10⁻⁷ m
We calculate the frequency of the light as follows:
ν = c/λ = (2.998 x 10⁸ m/s)/(5.49 x 10⁻⁷ m) = 5.46 x 10¹⁴ s⁻¹ = 5.46 x 10¹⁴ Hz
