A student finds a piece of metal and finds its mass to be 750 g. Through water displacement thestudent determines the volume to be 65.8 cm". Which metal does the student have?
Metals normally have different densities, so we can try to determine which metal is this by its density.
Assuming it is pure, the density of the metal is its mass divided by its volume:
[tex]\begin{gathered} \rho=\frac{m}{V} \\ \rho=\frac{750g}{65.8cm^3} \\ \rho\approx11.4g/cm^3 \end{gathered}[/tex]Now, we need to look for some table with densities of various metals and see which one has the density we found, 11.4 g/cm³.
Since we don't have one, we can look for one. In it, we can see that the only metal with this density is lead.
So, the metal in the question should be lead.
A gas occupying 0.6 L at 1.70 atm expands to 0.9 L. What is the new pressure assuming temperature remains constant?
Answer:
1.13 atmExplanation:
The new pressure can be found by using the formula
P1V1 = P2V2
P1 is the initial pressure
P2 is the final pressure
V1 is the initial volume
V2 is the final volume
Since we're finding the new pressure P2 we make P2 the subject
We have
[tex]p_2 = \frac{p1v1}{v2} \\ [/tex]
P1 = 1.7 atm
V1 = 0.6 L
V2 = 0.9 L
We have
[tex]p_2 = \frac{1.7 \times 0.6}{0.9} = 1.13333...\\ [/tex]
We have the final answer as
1.13 atmHope this helps you
At 302 K , to what pressure can the carbon dioxide in the cartridge inflate a 3.05 L mountain bike tire? (Note that the gauge pressure is the difference between the total pressure and atmospheric pressure. In this case, assume that atmospheric pressure is 14.7 psi .)
Ideal gas law is valid only for ideal gas not for vanderwaal gas. Therefore the carbon dioxide in the cartridge inflate a 3.05 L mountain bike tire to 104.3psi pressure.
What is ideal gas equation?Ideal gas equation is the mathematical expression that relates pressure volume and temperature.
Mathematically,
PV=nRT
where,
P = pressure
V= volume=3.05 L
n =number of moles=1mole(assumed as it is not given in question)
T =temperature = 302 K
R = Gas constant = 0.0821 L.atm/K.mol
P × 3.05 L =1 mole× 0.0821 L.atm/K.mol × 302 K
P =8.12atm
1 atm = 14.7 psi
Hence Pressure in psi = 8.12atm×14.7 psi = 119.49 psi
Pressure by the gas= Total pressure - Atmospheric pressure = 119.49 - 14.7 psi = 104.3psi
Therefore the carbon dioxide in the cartridge inflate a 3.79 L mountain bike tire to 104.3psi pressure.
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Lithium nitride is an ionic compound. Draw a diagram which shows its formula, the charges on the ions and the arrangement of the valency (outer shell) electrons around the negative ion. Use x for an electron from a lithium atom and o for an electron from a nitrogen atom.
Lithium nitride is an ionic compound and the chemical formula of lithium nitride is Li₃N and the charges on the ions is Li⁺¹N³⁻ 3 valence electron in lithium and 5 valence electron in nitrogen
Ionic compound is the ion compound these ions are atom that gain or lose electron resulting in a net positive and negative charges and lithium nitride is an ionic compound and in that Li⁺¹N³⁻ is the ion and the arrangement of the valency (outer shell) electrons are 3 valence electron in lithium and 5 valence electron in nitrogen
X = 3 electron
O = 7 electron
And that's why lithium nitride has 10 electron
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3. If you need to produce 85 g of CO2, how many grams of: (these are 3 problems starting with thea. C3H8, do you need?same amount:b. O2, do you need?c. H2O will also be made?
1) First let's write the equation. It is a combustion reaction, so:
C₃H₈ + O₂ ---> CO₂ + H₂O
and balance the equation (same number of atoms of each element on both sides of the equation):
C₃H₈ + 5 O₂ ---> 3 CO₂ + 4 H₂O
Reactant side:
C - 3
H - 8
O - 10
Product side:
C - 3
O - 10
H - 8
2) Now let's transform 85 grams of CO₂ into mole. For this, we use the following equation:
mole = mass/molar mass
Molar mass of CO₂ is: (1×12) + (2×16) = 44 g/mol
mole = 85/44
mole = 1.9 mol of CO₂
3) Now we use the proportion of the balanced equation:
1 mol of C₃H₈ ---- 3 mol of CO₂
x mol of C₃H₈ ----- 1.9 mol of CO₂
x = 0.6 mol of C₃H₈
4) Now we transform mole of C₃H₈ into grams using its molar mass.
molar mass of C₃H₈ is: (3×12) + (8×1) = 44 g/mol
mass = mole × molar mass
mass = 0.6 × 44
mass of C₃H₈ = 28 g
Answer: a) mass of C₃H₈ = 28 g
For alternative b we follow the same process starting from step 3:
3)Now we use the proportion of the balanced equation:
5 mol of O₂ ---- 3 mol of CO₂
x mol of O₂ ----- 1.9 mol of CO₂
x = 3.16 mol of O₂
4) Now we transform mole of O₂ into grams using its molar mass.
molar mass of O₂ is: (2×16) = 32 g/mol
mass = mole × molar mass
mass = 3.16 × 32
mass of O₂ = 101 g
Answer: b) mass of O₂ = 101 g
For alternative c we follow the same process starting from step 3:
3) Now we use the proportion of the balanced equation:
4 mol of H₂O ---- 3 mol of CO₂
x mol of H₂O ----- 1.9 mol of CO₂
x = 0.84 mol of H₂O
4) Now we transform mole of H₂O into grams using its molar mass.
molar mass of H₂O is: (2×1) + (1×16) = 18 g/mol
mass = mole × molar mass
mass = 0.84 × 18
mass of H₂O = 15 g
Answer: c) mass of H₂O = 15 g
List two components of rocket fuel?
A component that many space agencies use is liquid hydrogen, which can be abbreviated as LH2.
And another fuel very used in rockets is kerosene which is a hydrocarbons mixture of other compounds that fuel.
Answer:
Most liquid chemical rockets use two separate propellants: a fuel and an oxidizer. Typical fuels include kerosene, alcohol, hydrazine and its derivatives, and liquid hydrogen. Many others have been tested and used. Oxidizers include nitric acid, nitrogen tetroxide, liquid oxygen, and liquid fluorine.
Explanation:
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Find the element that is oxidized and the one that is reduced Si + 2 F2 --> SiF4
Answer
The element that is oxidized is Si and the one that is reduced is F₂.
Explanation
Si + 2F₂ → SiF₄
The given reaction is an oxidation-reduction (redox) reaction:
Oxidation: Si → Si⁴⁺ + 4e⁻
Reduction: 2F₂ + 4e⁻ → 4F⁻
Si is a reducing agent, and F₂ is an oxidizing agent.
An oxidizing agent gains electrons and is reduced in a chemical reaction.
A reducing agent loses electrons and is oxidized in a chemical reaction.
Therefore, the element that is oxidized is Si and the one that is reduced is F₂.
The following lists consists of ionic compounds EXCEPT
barium hydroxide, zinc carbonate, ammonium sulfate
calcium chloride, carbon disulfide, magnesium nitrate
sodium sulfate, copper(II) oxide, potassium nitride
aluminium sulfide, sodium sulfite, calcium fluoride
The following lists consists of ionic compounds except carbon disulfide (CS₂).
Barium hydroxide , Ba(OH)₂ is an ionic compound.
zinc carbonate, ZnCO₃ is an ionic compound.
ammonium sulfate , (NH₄)₂SO₄ is an ionic compound.
calcium chloride, CaCl₂ is an ionic compound.
carbon disulfide, CS₂ is not an ionic compound. In carbon disulfide both the elements are non metallic elements. The bond formed between atoms are by sharing of electron known as covalent bond due to very little difference in electronegativity.
magnesium nitrate, Mg(NO₃)₂ is an ionic compound.
sodium sulfate, Na₂SO₄ is an ionic compound.
copper(II) oxide, CuO is an ionic compound.
potassium nitride KNO₃ is an ionic compound.
aluminium sulfide, Al₂S₃ is an ionic compound.
sodium sulfite, Na₂S is an ionic compound.
calcium fluoride, CaF₂ is an ionic compound.
Thus, The following lists consists of ionic compounds except carbon disulfide (CS₂).
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What impact did cargo ship refrigeration systems have on the banana industry? Refrigeration slows the rate at which food is being spoiled, refrigeration does not affect speed at which the ship moves, refrigeration does not cause ripening, refrigeration does not control the sugar content of bananas?
Answer
Refrigeration slows the rate at which food is being spoiled
Explanation
One of the importance of storing foods at cold temperatures (refrigeration) is to slow the growth of microorganisms, thereby limiting food poisoning while preserving food's nutritional qualities and good taste.
Therefore, the impact the cargo ship refrigeration systems have on the banana industry is:
Refrigeration slows the rate at which food is being spoiled
What is the largest possible electronegativity difference for a bond to be covalent?A.0.5B.1.7C.0.0D.1.0
Answer
B. 1.7
Explanation
As a rule, an electronegativity difference of 2 or more on the Pauling scale between atoms leads to the formation of an ionic bond. A difference of less than 2 between atoms leads to covalent bond formation.
Therefore, the largest possible electronegativity difference for a bond to be covalent is 1.7
17. Which of the following represents a formula for a chemical compound?A. CB. KOHC. O
KOH. Option B is correct
Explanations:A chemical compound are made up of more than one element combined together. According to the question, we need to determine the formula that represents a compound.
The compound there is KOH since it contains three elements (Potassium, Oxygen and Hydrogen)
How many atoms of O are there in 7.00 g FeSO4 ?
Answer:
1.11 x 10²³ atoms O
Explanation:
To find the number of oxygen atoms in FeSO₄, you need to (1) convert FeSO₄ from grams to moles (using the molar mass), then (2) convert moles FeSO₄ to moles O (using the mole-to-mole ratio of FeSO₄), and then (3) convert moles O to atoms O (using Avogadro's Number). It is important to arrange the conversions/ratios in a way that allows for the cancellation of units (the desired unit should be in the numerator). The final answer should have 3 sig figs like the given number (7.00 = 3 sig figs).
Atomic Mass (Fe): 55.845 g/mol
Atomic Mass (S): 32.065 g/mol
Atomic Mass (O): 15.999 g/mol
Molar Mass (FeSO₄): 55.845 g/mol + 32.065 g/mol + 4(15.999 g/mol)
Molar Mass (FeSO₄): 151.906 g/mol
1 mole FeSO₄: 1 mole Fe, 2 mole S, 4 moles O
Avogadro's Number:
6.022 x 10²³ atoms = 1 mole
7.00 g FeSO₄ 1 mole 4 moles O 6.022 x 10²³ atoms
----------------------- x ------------------- x ----------------------- x ----------------------------
151.906 g 1 mole FeSO₄ 1 mole
= 1.11 x 10²³ atoms O
17 was found from determination in a mass spectrometer that an element X has three Isotopes whose mass are & 19.19,20.99 and 21.99 respectively The abundance of these I sotopes are 90.92% 0.25% $8.83% respectively Calculate the relative atomic mass.
The relative atomic mass of the given element is 40.372 amu.
What is relative atomic mass?The relative atomic mass of an element is considered as the sum of the isotopes masses each multiplied by the percentage which is found in nature.
The formula which is used to calculate the relative atomic mass is
Relative atomic mass = sum of all atomic masses of isotopes × fractional abundance
Given,
Mass of isotopes 1 = 19.19 amu
Mass of isotopes 2 = 20.99 amu
Mass of isotopes 3 = 21.99 amu
Fractional abundance of isotope 1 = 0.9092
Fractional abundance of isotope 2 = 0.0025
Fractional abundance of isotope 3 = 0.0883
By substituting all the values, we get
[( 19.19 × 0.9092) + (20.99 × 0.0025) + (21.99 × 0.883)]
= 17.447 + 0.052 + 22.873
= 40.372 amu.
Thus, we concluded that the relative atomic mass of the given element is 40.372 amu.
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Usually scientists will a large isotope such as Uranium-235 with a ____.
The collision results in several more nuclear fissions, also known as a _____. This results in a HUGE release in energy!
Usually, scientists will collide a large isotope such as Uranium-235 with a neutron. The collision results in several more nuclear fissions, also known as a chain reaction. This results in a HUGE release of energy!
What is nuclear fission?Nuclear fission is a type of nuclear reaction in which a large isotope such as uranium-235b is split into two or more smaller isotopes with the release of large quantities of energy and radiation.
The process of nuclear fission in large isotopes can be initiated by colliding or bombarding these large isotopes with fast-moving neutrons which splits the nucleus of the atom, releasing energy ad more neutrons that will split more atoms of the large isotope, resulting in a chain reaction.
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What is the balanced chemical equation for the reaction of sodium and oxygen?Na + O to NaO2Na + O2 to 2 NaO4Na + O2 to 2Na2ONa + O2 to NaO2
Answer
4Na + O₂ → 2Na₂O
Explanation
Sodium reacts with oxygen to form sodium oxide and has the following balanced chemical equation:
4Na + O₂ → 2Na₂O.
Hence, the balanced chemical equation for the reaction of sodium and oxygen is:
4Na + O2 to 2Na2O
the atomic masses of the two stable isotopes of beam
10.81amu
Explanations:In order to get the average atomic mass of an element, we need the following parameters:
• Natural Abundance (NA),: The percentage of atoms for an element that is a specific isotope.
• Mass (m) ,of each isotope
For the given element (Boron-10 and Boron-11), the natural abundances are 19.78% and 80.22% respectively.
The atomic masses of Boron-10 and Boron-11 are 10.0129amu and 11.0093amu respectively
The formula for calculating the average atomic mass of the element is expressed as:
[tex]AAM=(NA_a\times m_a)+(NA_b\times m_b)[/tex]Substitute the given parameters into the formula to have:
[tex]A\mathrm{}A\mathrm{}M=(0.1978\times10.0129)+(0.8022\times11.0093)[/tex]Simplify the resulting expression to have:
[tex]\begin{gathered} A\mathrm{}A\mathrm{}M=1.98055162+8.83166046 \\ A\mathrm{}A\mathrm{}M=10.81221208 \\ A\mathrm{}A\mathrm{}M\approx10.81amu \end{gathered}[/tex]Therefore the average atomic mass of Boron is 10.81amu to two decimal places.
Write a balanced equation for the decomposition reaction that occurred in Experiment 2. Include physical states.
calculate the theoretical and % yield of copper when 0.500 g of Cu was used and 0.350 g were recovered at the end of the experiment. complete solution
The theoretical percentage yield of copper is 70%
This is further explained below.
What is a yield?Generally, the equation for yield is mathematically given as
[tex]yield =\frac{\text { mote no. of product }}{\text { mote no. of reactant }} \times 100$[/tex]
Here, Based on Theoretical Yield
[tex]\begin{aligned} \text { mole rio. of reactant } &=-\frac{0.5}{63.546} \text { mole } \\ \end{aligned}$[/tex]
Based on the Actual yield
mole rio. of Product=0.35/63.546 mole
(Here atomic man of Cu=63.546g/mol )
Therefore, we apply the initially stated equation for %yield
So, %yield =[tex]\frac{\frac{0.35}{63.546}}{\frac{0.5}{(63.546}} \times 100 \%$[/tex]
=[tex]\frac{0.35}{0.5} \times 100 \%\\[/tex]
=0.7 *100%
=70%
In conclusion, the percentage yield is 70%
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The value of AH rxn for the following reaction is -72 kJ. How many kJ of heat is released when 0.989 g of HBr (80.91 g/mol) is formed? H2 (g) + Br2 (g) -› 2 HBr (gram). A. -144B. -72 C. -0.44 D. -36
Answer:
[tex]C\text{ : -0.44 KJ}[/tex]Explanation:
Here, we want to get the amount of heat released in KJ
From the change in enthalpy given and the equation of reaction, we know that 2 moles of HBr would lead to that amount of heat
Now, let us get the actual amount of heat released
We need to get the actual number of moles of HBr produced
Mathematically, we can calculate that by dividing the mass of HBr by its molar mass
We have that as:
[tex]\frac{0.989}{80.91}\text{ = 0.0122 mol}[/tex]From the reaction information:
-72 KJ was released by 2 moles
x KJ would be released by 0.0122 mol
To get the value of x, we have it that:
[tex]\begin{gathered} x\text{ }\times2\text{ = 0.0122 }\times\text{ \lparen-72\rparen} \\ \\ x\text{ = -36 }\times\text{ \lparen0.0122\rparen = -0.44 KJ} \end{gathered}[/tex]The pH of a basic solution is 8.13. What is [OH⁻]?
The [OH⁻] of the solution with pH of 8.13 is 1.35 * 10-6 M
pH is the measurement of the acidity or basicity of a compound by measuring [H⁻] ions in the solution. It ranges from 0 to 14 with acidic range from 0 – 7 and basic range from 7-14.
pOH is the measurement of the acidity or basicity of a compound by measuring [OH⁻] ions in the solution.
Thus, pH + pOH = 14
pOH = 14 - pH = 14 – 8.13 = 5.87
pOH = - log ([OH⁻])
- log ([OH⁻]) = 5.87
Log ([OH⁻]) = - 5.87
[OH⁻] = 10 ^ - 5.87 = 0.00000134896
[OH⁻] = 1.35 * 10⁻⁶ M
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Can someone draw this for me?
Btw you don't need real gumdrops or toothpicks you just need to draw it.
I'll mark the brainliest.
Both calcium oxide and carbon dioxide are inorganic compounds where calcium oxide is an ionic compound with a positive end at calcium and negative end at oxygen and carbon dioxide is a covalent compound formed by two double bonds between carbon and each oxygen.
What is calcium oxide?Calcium oxide is also called soda lime which is an inorganic compound formed by the ionic bonding of oxygen and calcium. Calcium is a metal and it is electron rich with 2 valence electrons.
Oxygen is electronegative gas, having 6 valence electrons and require two electrons to be stable. Thus calcium donates its two electrons to oxygen making calcium a positive ions and oxygen a negative ion.
In carbon dioxide, carbon have a valency of four thus, it forms 4 bonds with two oxygens. Double bonds are formed with each oxygen as shown in the image. These bonds are formed by electron sharing and is called covalent.
Calcium carbonate is formed by passing carbon dioxide through lime (CaO) in which Ca exists as Ca²⁺ ion and carbonate as an anion with three negative charges residing on 2 oxygens in CO₃.
Therefore, the structure of each of these compounds depends on the type of bonds between the atoms and it is depicted in the uploaded image.
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Calculate the total energy of 9.4 * 10^16 photons of visible light with a wavelength of 4.3 * 10^7 m.
According to the Planck's equation which is E= hc/λ the total energy of 9.4×10¹⁶ photons is 43.446×10[tex]^-17[/tex] J.
What is Planck's equation?Max Planck discovered the theory which stated that energy is transferred in the form of discrete packs which are called quanta and thus proposed an equation called the Planck's equation which relates energy and frequency of a photon and is given as, E=hcυ or in terms of wavelength it is ,E=hc/λ.
The equation makes use of a constant which is called the Planck's constant and it's value is 6.626×10[tex]^-34[/tex] Js.
Substituting the given value of wavelength of one photon in the above formula containing wavelength,E=6.626×10[tex]^-34[/tex]×3×10⁸/4.3×10⁷=4.622×10[tex]^-33[/tex] J.
Now, for energy of 9.4×10¹⁶ photons =4.622×10[tex]^-33[/tex]×9.4×10¹⁶=43.446×10[tex]^-17[/tex] J.
Thus, the energy of 9.4×10¹⁶ photons is 43.446×10[tex]-17[/tex] J.
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One day in lab, while adding a gnarled root to a dark liquid bubbling in an iron cauldron, your friend Leila (an expert chemist) says this:
"Group 1A metal hydrides react with water to produce hydroxides and hydrogen gas."
Using Leila's statement, and what you already know about chemistry, predict the products of the following reaction.
Be sure your chemical equation is balanced!
KH(s)+ H2O(l)=
The balanced equation of the reaction of the metal hydride, KH, and water is given below:
KH (s) + H₂O(l) ---> KOH + H₂ (g) What are metal hydrides?Metal hydrides are compounds that are composed of a reactive metal chemically combined with hydrogen.
The hydrogen atom is less electropositive than the metal and will accept electrons from the metal to form the negative hydride ion.
For example, Group 1A metal hydrides react with water to produce hydroxides and hydrogen gas.
Considering the above property, the given reaction will be:
KH (s) + H₂O(l) ---> KOH + H₂ (g)
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what is the volume (in liters) of a 4.2 gram sample of O2 at STP
to solve this we need to use the ideal gas law:
[tex]PV=nRT[/tex]we need to calculate the number of mols of O2
[tex]n=\frac{m}{Mm}=\frac{4.2g}{32\text{ g/mol}}=0.131mol[/tex]Now we just have to solve for volume and use the number of mols just calculated and the standard pressure (1 atm) and temperature 273.15K:
[tex]V=\frac{nRT}{P}=\frac{0.131mol\cdot0.082\text{ }\frac{atm\cdot l}{K\cdot mol}273.15K}{1atm}=2.94l[/tex]Name three different forms of mixture
Answer:
Mixtures can be classified on the basis of particle size into three different types: solutions, suspensions and colloids. The components of a mixture retain their own physical properties.
Sorry for the bad English, love from Vanuatu!
Explanation:
Write formulas or names as appropriate for each of the following ionic compounds. 1. Magnesium nitride 6. SrI2 2. Lithium oxide 7. Ba3(PO4)2 3. Aluminum sulfite 8. (NH4)2O 4. Copper(II) bicarbonate 9. Fe(ClO)3 5. Sodium nitrate 10. ZnCrO4
We have the following formulas for the given compounds:
1. Magnesium nitride ---> Mg3N2
2. Lithium oxide ---> Li2O
3. Aluminum sulfite ---> Al2(SO4)3
4. Copper (II) bicarbonate ---> Cu(HCO3)2
5. Sodium nitrate ---> NaNO3
For the given formulas we have the following names:
6. SrI2 ---> Strontium iodide
7. Ba3(PO4)2 --->Barium phosphate
8. (NH4)2O ---> Ammonium oxide
9. Fe(ClO)3 ---> Iron(III) hypochlorite
10. ZnCrO4 ---> zinc chromate
A silver ring is composed of 1.81×1023 atoms. Calculate the mass of the ring in grams.
Mole equation: [tex]n=\dfrac{m}{MM}[/tex]
n = number of moles (mol)m = mass (g)MM = molar mass (g/mol)To find mass given number of atoms:
Divide number of atoms by the number of atoms in the chemical formula ⇒ find number of moleculesDivide number of molecules by Avogadro's number ([tex]6.02*10^{23}[/tex]) ⇒ find number of moles (n)Solve for m using moles equationSolving the QuestionWe're given:
Ag (silver)Atoms = [tex]1.81*10^{23}[/tex] atomsm = ?In the chemical formula, which is Ag, there is only 1 atom.
Divide [tex]1.81*10^{23}[/tex] atoms by 1 atom to get the number of molecules in the silver ring:
[tex]1.81*10^{23}\div 1\\=1.81*10^{23}[/tex]
Therefore, there are [tex]1.81*10^{23}[/tex] molecules in the silver ring.
Now, divide [tex]1.81*10^{23}[/tex] molecules by Avogadro's number to find n:
[tex]\dfrac{1.81*10^{23}}{6.02*10^{23}}\\\\=\dfrac{1.81}{6.02}\\\\=\dfrac{1.81}{6.02}\\\\= 0.30066[/tex]
Therefore, the sample has 0.30066 mol.
Finally, solve for the mass using the moles equation:
[tex]n=\dfrac{m}{MM}[/tex]
⇒ Rearrange the equation:
[tex]m=n*MM[/tex]
⇒ MM of Ag = 107.87 g/mol
⇒ Plug in given information:
[tex]m=0.30066* 107.87\\m=32.4[/tex]
Therefore, the mass of the ring is 32.4 g.
Answer
32.4 g
Classify CH3CH2NH2 as astrong base or a weak base.Strong BaseWeak Base
Answer:
CH3CH2NH2 is a weak base.
Explanation:
CH3CH2NH2 is a weak base since its Kb is small, and thus it partially dissociates.
Which of the following is the ground-state electron configuration of a calcium atom?
O a. [Ne]3s²
O b. [Ne]3s²3p6
OC. [Ar]3d²
O d. [Ar]4s²
O e. [Ar]4s¹3d1
The arrangement of electrons in orbitals around an atomic nucleus is known as electronic configuration. It is also known as electronic structure or electron configuration. It follows Aufbau's principle, Hund's rule and Pauli's exclusion principle, to fill the electrons in various orbitals according to the energy of the orbitals.
Calcium has 20 electrons, that is, the atomic number of Ca = 20
Hence its electronic configuration will be, 1[tex]s^{2}[/tex] 2[tex]s^{2}[/tex] 2[tex]p^{6}[/tex] 3[tex]s^{2}[/tex] 3[tex]p^{6}[/tex] 4[tex]s^{2}[/tex]
Now, since Argon has 18 electrons, that is, the atomic number of Ar = 18, its electronic configuration will be,
Ar = 1[tex]s^{2}[/tex] 2[tex]s^{2}[/tex] 2[tex]p^{6}[/tex] 3[tex]s^{2}[/tex] 3[tex]p^{6}[/tex]
Thus , the simplified electronic configuration of Calcium is,
Ca = [Ar]4[tex]s^{2}[/tex]
Thus, option d) [Ar]4[tex]s^{2}[/tex] is the correct answer.
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Determine the percent composition of hydrogen for the following: NaHCO3
By definition, the percent composition of an atom in a compound is its mass percentage in the formula.
That is, if we have 1 mol of NaHCO₃, we have also 1 mol of H (because there is only on H for each molecule).
So, we calculate the mass of this 1 mol of NaHCO₃ and the mass of 1 mol of H and calculate the percentage.
In equations, we want the following:
[tex]C_H=\frac{m_H}{m_{NaHCO_{3}}}[/tex]Since these are ratios, we doesn't matter if we talk about 1, 2 or any number of moles, but 1 mol is easier because the molecular and atomi masses are for 1 mol.
The molecular mass of NaHCO₃ is:
[tex]\begin{gathered} M_{NaHCO_3}=M_{Na}+M_H+M_C+3\cdot M_O \\ M_{NaHCO_3}\approx(22.990+1.008+12.011+3\cdot15.999)g/mol \\ M_{NaHCO_3}\approx84.006g/mol \end{gathered}[/tex]Which means that we have approximately 84.006 grams of NaHCO₃ in 1 mol of it.
The atomic mass of H is:
[tex]M_H\approx1.008g/mol[/tex]Which means that we have approximately 1.008 grams of H in 1 mol of it.
Now, we can take the percentage of mass of H:
[tex]C_H\approx\frac{1.008g_{}}{84.006g}\cdot100\%\approx1.20\%[/tex]So, the percentage composition of H in NaHCO₃ is approximately 1.20%.