The correct answer is C. There is no oxygen in space, so there can be no combustion.
Explanation:
Fire and flames are the result of a chemical process known as combustion. Moreover, for combustion to occur there are two essential elements. The first one is a fuel or a substance that releases energy and ignites, and the second one is an oxidant, which accepts electrons. This mix and reaction causes high temperatures and release of heat in the form of fire and flames.
This implies, that for fireballs or any other form of fire to exist there must be oxygen or any substance that replaces it. This does not occur in space because the levels of oxygen are extremely low, this means, at least oxygen is added fireballs are not possible in this context as there is no oxygen, and therefore no combustion (Option C).
Answer:
C.) There is no oxygen in space, so there can be no combustion.
Explanation:
I got it correct on founders edtell
What is the molar mass of a protein if a solution of 0.020 g of the protein in 25.0 mL of solution has an osmotic pressure of 0.56 torr at 25 ∘ C
Answer:
26.5 kD
Explanation:
Here we can apply the formula ∏ = iMRT, where ∏ = osmotic pressure = 0.56 - ( given ). This is only one part of the information we are given / can conclude in this case ....
i = van’t Hoff factor = 1 for a protein molecule,
R = gas constant = 62.36 L torr / K-mol,
T ( temperature in Kelvin ) = 25 + 273 - conversion factor C° + 273 = 298K
( Known initially ) ∏ = osmotic pressure = 0.56 torr
..... besides the part " M " in the formula, which we have no information on whatsoever, as we have to determine it's value.
_____
Substitute derived / known values to solve for M ( moles / liter ) -
∏ = iMRT
⇒ 0.56 = ( 1 )( M )( 62.36 )( 298 )
⇒ 0.56 = M( 18583.28 )
⇒ M = 0.56 / 18583.28 ≈ 0.00003013461 ....
_____
We know that M = moles / liter, so we can use this to solve for moles, and hence calculate the molar mass by the formula molar mass = g / mol -
M = mol / l
⇒ 0.00003013461 = 0.020 / 25 mL ( 0.025 L ),
0.020 / 0.025 = 0.8 g / L
⇒ 0.8 g = 0.00003013461 moles,
molar mass = 0.8 g / 0.00003013461 moles = 26,548 g / mol = 26.5 kD
The atomic number of an element is 31 and the mass number of one of its atoms is 65. This atom contains: a 31 neutrons b 34 protons c 65 protons d 34 neutrons e 34 electrons
Answer:
d, 34 neutrons
Explanation:
Mass number is the sum of the number of protons and the number of neutrons.
Atomic number equals to the number of protons.
Since the element has an atomic number of 31, it has 31 protons. The number of neutrons equal to mass number - no. of protons,
which in this case is 65 - 31
= 34 neutrons.
In a neutral atom, the no. of electrons equal to the no. of protons, because each proton carries a +1 charge and each electron carries a -1 charge. To cancel out the charge, their numbers must be equal. So, this atom has 31 electrons.
From the options, only d is correct. (34 neutrons)
Write the electron configuration for the element titanium, TiTi. Express your answer in order of increasing orbital energy as a string without blank space between orbitals. For example, the electron configuration of LiLi could be entered as 1s^22s^1 or [He]2s^1.
Answer:
1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d² or [Ar] 3d² 4s²
Explanation:
Electron configuration can basically be referred to as the location of electron; how the electrons are arranged in the orbitals of the atoms.
Following Aufbau principle, electrons are arranged in the following order of orbitals.
1s 2s 2p 3s 3p 4s 3d and so on.
The s can hold a maximum of 2 electrons, p can hold a maximum of 6 electrons and d can hold a maximum of 10 electrons.
Titanium has an atomic number of 22. So the arrangement is given as;
Ti = 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d²
The short hand notation is given as;
[Ar] 3d² 4s²
The electron configuration of Ti is
[tex]Ti: 1s^{2} 2s^{2} 2p^{6} 3s^{2} 3p^{6} 4s^{2} 3d^{2}[/tex] or [tex]Ti: [Ar] 4s^{2} 3d^{2}[/tex]
The electron configuration of an element is the distribution of electrons in atomic orbitals.
According to Aufbau's principle, the orbitals with lower energies are filled before the orbitals with higher energies.
We can know this order, using the diagonal rule (attached image).
The maximum number of electrons in each sublevel is:
s = 2p = 6d = 10f = 14Considering all these facts, and that Titanium has 22 electrons, the electron configuration of Ti is:
[tex]Ti: 1s^{2} 2s^{2} 2p^{6} 3s^{2} 3p^{6} 4s^{2} 3d^{2}[/tex]
Since [tex]1s^{2} 2s^{2} 2p^{6} 3s^{2} 3p^{6}[/tex] is the electron configuration of Argon, this can also be written as:
[tex]Ti: [Ar] 4s^{2} 3d^{2}[/tex]
The electron configuration of Ti is
[tex]Ti: 1s^{2} 2s^{2} 2p^{6} 3s^{2} 3p^{6} 4s^{2} 3d^{2}[/tex] or [tex]Ti: [Ar] 4s^{2} 3d^{2}[/tex]
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A buffered solution containing dissolved aniline, C6H5NH2, and aniline hydrochloride, C6H5NH3Cl, has a pH of 5.57 . A. Determine the concentration of C6H5NH+3 in the solution if the concentration of C6H5NH2 is 0.200 M. The pKb of aniline is 9.13. g
Answer:
[C₆H₅NH₃⁺] = 0.0399 M
Explanation:
This excersise can be easily solved by the Henderson Hasselbach equation
C₆H₅NH₃Cl → C₆H₅NH₃⁺ + Cl⁻
pOH = pKb + log (salt/base)
As we have value of pH, we need to determine the pOH
14 - pH = pOH
pOH = 8.43 (14 - 5.57)
Now we replace data:
pOH = pKb + log ( C₆H₅NH₃⁺/ C₆H₅NH₂ )
8.43 = 9.13 + log ( C₆H₅NH₃⁺ / 0.2 )
-0.7 = log ( C₆H₅NH₃⁺ / 0.2 )
10⁻⁰'⁷ = C₆H₅NH₃⁺ / 0.2
0.19952 = C₆H₅NH₃⁺ / 0.2
C₆H₅NH₃⁺ = 0.19952 . 0.2 = 0.0399 M
A study of the system, 4NH3(g) + 7O2(g) <--> 2N2O4(g) + 6H2O(g), was carried out. A system was prepared with [NH3] = [O2] = 3.60 M as the only components initially. At equilibrium, [N2O4] is 0.600 M. Calculate the equilibrium concentration of NH3(g).
Answer:
The equilbrium concentration of NH₃(g) is 2.4 M
Explanation:
The balanced reaction is:
4 NH₃(g) + 7 O₂(g) ⇔ 2 N₂O₄(g) + 6 H₂O(g)
By stoichiometry of the reaction, 2 moles of N₂O₄ are formed from 4 moles of NH₃.
Considering that the concentration is [tex]concentration=\frac{number of moles}{volume}[/tex] and with a volume of 1 liter, it is possible to apply the following rule of three: if 2 M of N₂O₄ are formed from 4 M of NH₃, 0.6 M of N₂O₄ from what concentration of NH₃ are formed?
[tex]concentration of NH_{3}=\frac{0.6 M of N_{2}O_{3} *4MofNH_{3} }{2 M of N_{2}O_{3} }[/tex]
concentration of NH₃= 1.2 M
By subtracting the moles of NH3 in equilibrium from the moles of NH₃ initially, you will see how many moles of NH₃ were converted and remain in equilibrium: 3.6 M - 1.2 M= 2.4 M
The equilbrium concentration of NH₃(g) is 2.4 M
What is the name of the molecule below?
A) 2-pentene
B) pentane
C) 2-pentyne
D) 2-pentane
The name of the molecule which is given below is 2-pentene.
What are alkene?Alkenes are the organic compounds which are composed of carbon and hydrogen atoms, in which double bond is present.
In the given diagram:
Each corner and joints shows the carbon atoms and number of carbon atoms in it is 5.One double bond is present in the 2nd position.So the compound is 2 pentene.
Hence, 2 pentene is the name of the compound.
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Use the References to access important values if needed for this question.
For the following reaction, 3.83 grams of hydrogen gas are allowed to react with 9.60 grams of
ethylene (C2H4).
hydrogen(g) + ethylene (C2H4)(g) ethane (C2H)(g)
What is the maximum mass of ethane (C2H6) that can be formed?
grams
What is the FORMULA for the limiting reagent?
What mass of the excess reagent remains after the reaction is complete?
grams
Submit Answer
Retry Entire Group
9 more group attempts remaining
Answer:
A. 10.29 g of C2H6.
B. C2H4.
C. 3.14 g of H2.
Explanation:
Step 1:
We'll begin by writing the balanced equation for the reaction. This is given below:
C2H4 + H2 —> C2H6
Step 2:
Determination of the masses of C2H4 and H2 that reacted and the mass of C2H6 produced from the balanced equation.
This is illustrated below:
Molar mass of C2H4 = (12x2) + (4x1) =28 g/mol
Mass of C2H4 from the balanced equation = 1 x 28 = 28 g.
Molar mass of H2 = 2x1 = 2 g/mol
Mass of H2 from the balanced equation = 1 x 2 = 2 g.
Molar mass of C2H6 = (12x2) + (6x1) = 30 g/mol.
Mass of C2H6 from the balanced equation = 1 x 30 = 30 g
From the balanced equation above,
28 g of C2H4 reacted with 2 g of H2 to produce 30 g of C2H6.
Step 3:
Determination of the limiting reactant. This can be obtained as follow:
From the balanced equation above,
28 g of C2H4 reacted with 2 g of H2.
Therefore, 9.6 g of C2H4 will react with = (9.6 x 2)/28 = 0.69 g of H2.
From the calculations made above, we can see that only 0.69 g out of 3.83 g of H2 given is needed to react completely with 9.6 g of C2H4.
Therefore, C2H4 is the limiting reactant and H2 is the excess reactant.
A. Determination of the maximum mass of ethane, C2H6 produced from the react.
In this case, the limiting reactant will be used because it will produce the maximum yield of the reaction since all of it is consumed in the reaction.
The limiting reactant is C2H4 and the maximum mass of C2H6 can be obtained as follow:
From the balanced equation above,
28 g of C2H4 reacted to produce 30 g of C2H6.
Therefore, 9.6 gof C2H4 will react to produce = (9.6 x 30)/28 = 10.29 g of C2H6.
Therefore, 10.29 g of ethane, C2H6 were produced from the reaction.
B. The limiting reactant is ethylene with formula C2H4. Please refer to step 3 above for details.
C . Determination of the mass of the excess reactant that remained after the reaction.
The excess reactant is H2, please refer to step 3 above for details and the mass that remained after the reaction can be obtained as follow:
Mass of H2 given = 3.83 g
Mass of H2 that reacted = 0.69 g
Mass of H2 remaining =.?
Mass of H2 remaining = mass of H2 given – mass of H2 that reacted.
Mass of H2 remaining = 3.83 – 0.69
Mass of H2 remaining = 3.14 g
Therefore, 3.14 g of H2 remained after the reaction.
Calculate the entropy change for the reaction: HCl(g) + NH3(g) -> NH4Cl(s) Entropy data: HCl: 187 J/K mol NH3: 193 J/K mol NH4Cl: 94.6 J/K mol
Answer:
-285.4 J/K
Explanation:
Let's consider the following balanced equation.
HCl(g) + NH₃(g) ⇒ NH₄Cl(s)
We can calculate the standard entropy change for the reaction (ΔS°r) using the following expression.
ΔS°r = 1 mol × S°(NH₄Cl(s)) - 1 mol × S°(HCl(g)) - 1 mol × S°(NH₃(g))
ΔS°r = 1 mol × 94.6 J/K.mol - 1 mol × 187 J/K.mol - 1 mol × 193 J/K.mol
ΔS°r = -285.4 J/K
Answer:
-198.3 J/K mol
Explanation:
I got it correct on founders edtell
A 75.0 mL sample of 0.020 M acetic acid (HC2H3O2) is titrated with 0.020 M NaOH. ? Determine the pH of the solution before the addition of any NaOH. (Ka of acetic acid is 1.8 x 10-5) HC2H3O2 (aq) + H2O (l) D C2H3O2-(aq) + H3O+ (aq) (Hint: before titration so acid only, use ICE table)
Answer:
pH = 3.23
Explanation:
Before the addition of any NaOH, the only you have is a 0.020M acetic acid solution. That is in equilibrium with water as follows:
HC₂H₃O₂(aq) + H₂O(l) ⇄ C₂H₃O₂⁻(aq) + H₃O⁺(aq)
The Ka of this reaction is:
Ka = 1.8x10⁻⁵ = [C₂H₃O₂⁻] [H₃O⁺] / [HC₂H₃O₂]
Where [] are concentrations in equilibrium of each species
As you have in solution just HC₂H₃O₂, the equilibrium concentrations will be:
[HC₂H₃O₂] = 0.020M - X
[C₂H₃O₂⁻] = X
[H₃O⁺] = X
Where X is reaction coordinate.
Repalcing in Ka expression:
1.8x10⁻⁵ = [C₂H₃O₂⁻] [H₃O⁺] / [HC₂H₃O₂]
1.8x10⁻⁵ = [X] [X] / [0.020M - X]
3.6x10⁻⁷ - 1.8x10⁻⁵X = X²
3.6x10⁻⁷ - 1.8x10⁻⁵X - X² = 0
Solving for X:
X = -0.0006M → False solution. There is no negative concentrations
X = 0.000591M → Right solution.
As:
[H₃O⁺] = X
[H₃O⁺] = 0.000591M
As pH = -log[H₃O⁺]
pH = 3.23Decide which element probably has a density most and least similar to the density of lithium.
Answer:
Helium and potassium
Explanation:
The density of helium is 0.18 and potassium 0.86, while lithium is 0.53
Which is the correct way to write 602,200,000,000 ,000,000,000,000 in scientific notation
Answer:
6.022 × 10^23
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Calculate the number of ATP generated from one saturated 10 ‑carbon fatty acid. Assume that each NADH molecule generates 2.5 ATP and that each FADH2 molecule generates 1.5 ATP .
Answer:
Total ATP molecules produced = 66 molecules of ATP
Explanation:
A 10-carbon fatty acid when it has undergone complete oxidation will yield 5 acetyl-CoA molecules and 4 FADH₂ and 4 NADH molecules each. Each of the 5 acetyl-CoA molecules enters into the citric acid cycle and is completely oxidized to yield further ATP and FADH₂ and NADH molecules.
The total yield of ATP in the various enzymatic step is calculated below:
Acyl-CoA dehydrodenase = 4 FADH₂
β-Hydroxyacyl-CoA dehydrogenase = 4 NADH
Isocitrate dehydrogenase = 5 NADH
α-Ketoglutarate dehydrogenase = 5 NADH
Succinyl-CoA synthase = 5 ATP (from substrate-level phosphorylation of GDP)
Succinate dehydrogenase = 5 FADH₂
Malate dehydrogenase = 5 NADH
Total ATP from FADH₂ molecoles = 9 * 1.5 = 13.5
Total NADH molecules = 19 * 2.5 = 47.5
Total ATP molecules produced = 13.5 + 47.5 + 5
Total ATP molecules produced = 66 molecules of ATP
Answer:
Number of ATP generated = = [tex]64 ATPs[/tex]Explanation:
First, calculate the number of acetyl-CoA molecules formed:
Number of acetyl-CoA molecules = [tex]\frac{number of carbons in fatty acid}{2}[/tex]
[tex]= \frac{10}{2}\\\\ = 5 acetyl-CoA molecules[/tex]
Next, calculate the number of rounds of beta-oxidation:
Number of rounds = number of acetyl-CoA molecules - 1
[tex]= 5 - 1\\\\ = 4 rounds[/tex]
Calculate the number of ATP from NADH and FADH2:
If each NADH yields 2.5 ATPs and each FADH2 yields 1.5 ATPs, then multiply the number of rounds by 4 and multiply the number of acetyl-CoA molecules by 10.
[tex](4 * 4) + (5 * 10) = 66 ATP[/tex]
Subract two ATP molecules for activation of the fatty acid.
[tex]Total ATP = 66 - 2\\\\ = 64 ATPs[/tex]
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Which molecule or ion has a trigonal planar shape?
Answer:B
Explanation: A P E X
In nature, oxygen has three common isotopes. The atomic masses and relative abundances of these isotopes are given in the table below. Isotope Atomic Mass (amu) Relative Abundance O-16 15.995 99.759% O-17 16.995 0.037% O-18 17.999 0.204% Calculate the average atomic mass of oxygen. Show all of your calculations below.
Answer: The average atomic mass of oxygen is 15.999 amu
Explanation:
Mass of isotope O-16 = 15.995 amu
% abundance of isotope O-16= 99.759 % = [tex]\frac{99.759}{100}=0.99759[/tex]
Mass of isotope O-17 = 16.995 amu
% abundance of isotope O-17 = 0.037% = [tex]\frac{0.037}{100}=0.00037[/tex]
Mass of isotope O-18 = 17.999 amu
% abundance of isotope O-18 = 0.204% = [tex]\frac{0.204}{100}=0.00204[/tex]
Formula used for average atomic mass of an element :
[tex]\text{ Average atomic mass of an element}=\sum(\text{atomic mass of an isotopes}\times {{\text { fractional abundance}})[/tex]
[tex]A=\sum[(15.995\times 0.99759)+(16.995\times 0.00037)+(17.999 \times 0.00204)][/tex]
[tex]A=15.999[/tex]
Thus the average atomic mass of oxygen is 15.999 amu
Answer:
Converting the percent abundance into decimal form, we get:
O-16: 99.759% = 99.759/100 = 0.9975
O-17: 0.037% = 0.037/100 = 0.00037
O-18: 0.204% = 0.204/100 = 0.0020
Average atomic mass of oxygen is:
(15.995) x (0.9975) + (16.995) x (0.00037) + (17.999) x (0.0020)
= 15.955 + 0.0062 + 0.0359
= 15.997 amu
Explanation:
From PLATO
Re-order each list of elements in the table below, if necessary, so that the elements are listed in order of decreasing electronegativity.
Answer:
O, S, Te
Cl, Br, Se
Explanation:
Main group elements have an electronegativity that increases across a period (from left to right) and decreases down a group.
Each atom has its own value which you can find on the electronegativity chart.
Metals have low values
Nonmetals have high values
I'm your case:
O = 3.5
S = 2.5
Te = 2.1
Cl = 3.0
Br = 2.8
Se = 2.4
O, S, Te, and Cl, Br, Se are the correct order for the elements listed in order of decreasing electronegativity.
What is electronegativity?
Electronegativity. is the tendency or the efficiency of an atom to attract the lone pair of electrons towards itself to become stable and complete their octave is known as electronegativity.
In the periodic table oxygen, fluorine and nitrogen are the three top, most electronegative elements, and from moving up to down in periodic table electronegativity. decreases and left to right increases.
Therefore, the correct order for the elements listed in order of decreasing electronegativity is O, S, Te, and Cl, Br, Se.
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Using the Bohr model, determine the lowest possible energy, in joules, for the electron in the Li2+ ion.
Answer: E = - 19.611×[tex]10^{-18}[/tex] J
Explanation: The lowest possible energy can be calculated using the formula:
[tex]E_{n} = - Z^{2}.\frac{k}{n^{2}}[/tex]
where:
Z is atomic number of the atom;
k is a constant which contains other constants and is 2.179×[tex]10^{-18}[/tex] J
n is a layer;
For the lowest possible, n=1.
Atom of Lithium has atomic number of Z=3
Substituing:
[tex]E_{1} = - 3^{2}.\frac{2.179.10^{-18}}{1}[/tex]
[tex]E_{1} =[/tex] [tex]-19.611.10^{-18}[/tex] J
The energy for the electron in the [tex]Li^{+2}[/tex] ion is - 19.611 joules
The lowest possible energy, in Joules, for the electron in the [tex]Li^{2+}[/tex] ion is equal to [tex]1.96\times 10^{-17}\; Joules[/tex]
To determine the lowest possible energy, in Joules, for the electron in the [tex]Li^{2+}[/tex] ion, we would use the Bohr model:
Mathematically, Bohr's model is given by the equation:
[tex]Energy = -Z^2 \frac{k}{n^2}[/tex]
Where:
Z is the atomic number of an atom.n is the number of energy level.k is Rydberg constant.We know that the atomic number of lithium (Li) is equal to 3.
Also, at the lowest possible energy, n = 1.
Rydberg constant = [tex]2.179 \times 10^{-18}[/tex]
Substituting the parameters into the equation, we have;
[tex]E_1 = -3^2 \times \frac{2.179 \times 10^{-18}}{1^2} \\\\E_1 =9 \times 2.179 \times 10^{-18}\\\\E_1 =1.96\times 10^{-17}\; Joules[/tex]
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Qualitatively estimate the relative melting points for each of the solids, and rank them in decreasing order.
Rank from highest to lowest melting point. To rank items as equivalent, overlap them.
sodium chloride
graphite
solid ammonia
Answer:
Graphite> sodium chloride> solid ammonia
Explanation:
Melting points of solids has a lot to do with the nature of intermolecular forces in the solid. A substance melts when the intermolecular forces holding the crystal lattice has been overcome such that that the crystal structure of the solid just collapses.
Graphite consists of covalently bonded layers of carbon atom which form a giant lattice. The melting point of graphite is very high because of the fact that the strong covalent bonds that hold the carbon atoms together in the layers require a lot of heat energy to break. Grapoghite melts at about 3600°C
Sodium chloride is an ionic compound that melts at about 801°C. The lattice is composed of alternate sodium and chloride ions.
Solid ammonia is held together by much weaker intermolecular interaction hence it has a melting point of about −77.73 °C.
Where are the lanthanides and actinides found on the periodic table?
A. Columns 7 and 8
B. Columns 3 - 12, in the center of the table
C. Rows 6 and 7, separated from the rest of the table
D. Columns 1 and 2
Answer:
C. Rows 6 and 7, separated from the rest of the table
Explanation:
The lanthanides and actinides are groups of elements in the periodic table, that are thirty (30) in number. They are separated from the rest of the periodic table, usually appearing as separate rows at the bottom. They are often called the inner transition metals, because they all fill the f-block.
Therefore, the correct option is C
" They are found in Rows 6 and 7, separated from the rest of the table"
The accepted value of the number of Liters of gas in a mole is 22.4. List two possible reasons on why our experiment yielded a different value for the number of Liters in a mole of a gas.
Hint: Our experiment was conducted in July, in St. Paul, Minnesota.
Answer:
- Pressure in St. Paul, Minnesota
- Temperature in St. Paul, Minnesota
Explanation:
22.4 L or dm³ is the volume for a gas under Standard pressure and temperature conditions.
It is logically to say, that tempereature value at the day of the experiment was not 273.15 K, which is 32°F
We can say, that the pressure was not 1 atm. St Paul Minnesota has a minimum, but a little height, so the pressure differs by few figures from the standard pressure values.
We also have to mention, that 22.4 L is the value for the Ideal gases at standards conditions. Ideal gases does not exisist on practice, we always talk about real gases. Don't forget the Ideal Gases Law equation:
P . V = n . R . T
Pressure . Volume = number of moles . 0.082 L.atm /mol. K . 273.15K
Number of moles must be 1 at STP, to determine a volume of 22.4L
Carbon-14 has a half-life of 5720 years and this is a fast-order reaction. If a piece of wood has converted 75 % of the carbon-14, then how old is it?
Answer:
11445.8years
Explanation:
Half-life of carbon-14 = 5720 years
First we have to calculate the rate constant, we use the formula :
Solution A has a pH of 10, and solution B has a pH of 1. Which statement best describes these solutions?
Answer:
Solution A is a Weak Alkali, Solution B is a strong Acid.
Explanation:
At pH 10, the colour is blue, therefore it's a weak alkali.
At pH 1, the colour is red, therefore it's a strong Acid.
Why is the chemical formula Li2H incorrect? Select the correct answer below: A. There should be one lithium, not two. B. There should be one lithium and two hydrogens. C. Lithium does not react with hydrogen. D. There should be three lithiums, not two.
Answer:
There should be one lithium, not two.
Explanation:
Lithium reacts with hydrogen at about 750°C to yield lithium hydride (LiH). LiH is white and powdery in appearance. It releases hydrogen gas when it reacts with water.
The correct formula for Lithium hydride is LiH and not Li2H because both lithium and hydrogen are univalent. Lithium has a valency of +1 while hydrogen has a valency of -1 in lithium hydride. Hydrides are formed between hydrogen and highly electro positive metals. In hydrides, hydrogen is forced to accept an electron from the highly electro positive metal.
A strontium hydroxide solution is prepared by dissolving 10.60 gg of Sr(OH)2Sr(OH)2 in water to make 47.00 mLmL of solution.What is the molarity of this solution? Express your answer to four significant figures and include the appropriate units.
Answer:
Approximately [tex]1.854\; \rm mol\cdot L^{-1}[/tex].
Explanation:
Note that both figures in the question come with four significant figures. Therefore, the answer should also be rounded to four significant figures. Intermediate results should have more significant figures than that.
Formula mass of strontium hydroxideLook up the relative atomic mass of [tex]\rm Sr[/tex], [tex]\rm O[/tex], and [tex]\rm H[/tex] on a modern periodic table. Keep at least four significant figures in each of these atomic mass data.
[tex]\rm Sr[/tex]: [tex]87.62[/tex].[tex]\rm O[/tex]: [tex]15.999[/tex].[tex]\rm H[/tex]: [tex]1.008[/tex].Calculate the formula mass of [tex]\rm Sr(OH)_2[/tex]:
[tex]M\left(\rm Sr(OH)_2\right) = 87.62 + 2\times (15.999 + 1.008) = 121.634\; \rm g \cdot mol^{-1}[/tex].
Number of moles of strontium hydroxide in the solution[tex]M\left(\rm Sr(OH)_2\right) =121.634\; \rm g \cdot mol^{-1}[/tex] means that each mole of [tex]\rm Sr(OH)_2[/tex] formula units have a mass of [tex]121.634\; \rm g[/tex].
The question states that there are [tex]10.60\; \rm g[/tex] of [tex]\rm Sr(OH)_2[/tex] in this solution.
How many moles of [tex]\rm Sr(OH)_2[/tex] formula units would that be?
[tex]\begin{aligned}n\left(\rm Sr(OH)_2\right) &= \frac{m\left(\rm Sr(OH)_2\right)}{M\left(\rm Sr(OH)_2\right)}\\ &= \frac{10.60\; \rm g}{121.634\; \rm g \cdot mol^{-1}} \approx 8.71467\times 10^{-2}\; \rm mol\end{aligned}[/tex].
Molarity of this strontium hydroxide solutionThere are [tex]8.71467\times 10^{-2}\; \rm mol[/tex] of [tex]\rm Sr(OH)_2[/tex] formula units in this [tex]47\; \rm mL[/tex] solution. Convert the unit of volume to liter:
[tex]V = 47\; \rm mL = 0.047\; \rm L[/tex].
The molarity of a solution measures its molar concentration. For this solution:
[tex]\begin{aligned}c\left(\rm Sr(OH)_2\right) &= \frac{n\left(\rm Sr(OH)_2\right)}{V}\\ &= \frac{8.71467\times 10^{-2}\; \rm mol}{0.047\; \rm L} \approx 1.854\; \rm mol \cdot L^{-1}\end{aligned}[/tex].
(Rounded to four significant figures.)
An acetic acid buffer solution is required to have a pH of 5.27. You have a solution that contains 0.010 mol of Acetic acid. What molarity of sodium acetate will you need to add to the solution
Answer:
Molarity of sodium acetate you will need to add is 0.0324M
Explanation:
Assuming volume of the buffer is 1L.
The pH of a buffer can be determined using Henderson-Hasselbalch equation:
pH = pKa + log [A⁻] / [HA]
Where pKa is pKa of the weak acid, [A⁻] molar concentration of conjugate base and [HA] molar concentration of weak acid
Replacing for the acetic buffer (pKa = 4.76):
pH = 4.76 + log [Sodium Acetate] / [Acetic Acid]
As you have 0.010 moles of acetic acid in 1L:
[Acetic Acid] = 0.010mol / 1L = 0.010M
And you require a pH of 5.27:
5.27 = 4.76 + log [Sodium Acetate] / [0.010M]
0.51 = log [Sodium Acetate] / [0.010M]
10^0.51 = [Sodium Acetate] / [0.010M]
3.236 = [Sodium Acetate] / [0.010M]
3.236 [0.010M] = [Sodium Acetate]
0.0324M = [Sodium Acetate]
Molarity of sodium acetate you will need to add is 0.0324M
Citra is using the basic permanent wrap method to perm Holly's hair. As Citra divides Holly's hair into panels, how wide should she make them?
Answer:
Citra should make it equal to the length of the rod.
Explanation:
A basic permanent wrap method is a 9 section wrap method in which all the base sections are horizontal, having same length and width of the rod
Basic permanent wrap method causes a uniform curl from the scalp to the end of the hair.
In permanent wrap method, paneling the hair equal to the length will make the will give the same size as the rod.
The length of the rod determines the size of the curl.
Once Holly's hair is divided into panel and make it as wide as the length of the rod, it will curl in the same size as the rod lengths and the hair will perm well.
g What is the standard cell potential for the following reaction occurring in an electrochemical cell. The equation is balanced. 3 Cl2(g) + 2 Fe(s) → 6 Cl-(aq) + 2 Fe3+(aq) The following data may be helpful: Cl2(g) + 2 e- → 2 Cl-(aq) Eº = 1.36 V Fe3+(aq) + 3 e- → Fe(s) Eº = -0.036 V a) -1.40 V b) 1.40 V c) 2.84 V
Answer:
b) 1.40 V
Explanation:
Oxidation half equation;
2Fe(s) → 2Fe3+(aq) + 6 e-
Reduction half equation;
3Cl2(g) + 6 e- → 6 Cl-(aq)
E°cathode= 1.36 V
E°anode= -0.036 V
E°cell= E°cathode - E°anode
E°cell= 1.36 -(-0.036)
E°cell= 1.36 + 0.036
E°cell= 1.396 V
E°cell= 1.40 V
16. A metal element and a non-metal element are brought near each other and allowed to react. What's the most likely type of compound
that will form between these two elements?
A. lonic and covalent
B. lonic
C. Covalent
D. Neither, metals and non-metals don't react.
Answer:
B) Ionic
Explanation:
For each of the following names, write down the correct formula.
i. Silicon tetrafluoride
ii. Disulfur decafluoride
iii. Sulfur trioxide
iv. Diphosphorus pentoxide
v. Dichlorine oxide
Explanation:
I hope it helps you
good luck
Answer for the question
Which nonmetal is extremely nonreactive, refusing to bond with other elements except under very unusual conditions created in the laboratory?
Answer:
Helium
Explanation:
Though all noble gases are stable, helium only has two electrons and one shell so it basically doesn't have room for others.
If a gas is initially at a pressure of nine ATM and a volume at 21 L at a temperature of 253K and the pressure is raise to 15 ATM and the temperature is raised to 302K what will be the resulting volume of the gas
Answer:
15.0L
Explanation:
p/v = constan
(9*21)/253 =(15v)/ 302
v = (9*21*302)/(15*253)
v=15.0