Answer:
B
Explanation:
Chemical changes would mean changes that does not change in the form of matter.
A) water freezing in a pond is liquid to solid, so form of matter change, so it cannot be this one.
C) A tree buming is solid to gas, so form of matter change, so it cannot be this one.
D) Steam rising from pavement is solid to gas, so for of matter change, so it cannot be this one.
On the other hand B, the matter stays in the same form, solid.
Tree branch to a tree branch.
How many grams of water can be formed from the reaction of 8.76 grams of H2 with 10.5 liters of O2 (at STP) according to the balanced equation: 2 H2 + O2 --> 2 H2O Express your answer to 3 sig figs. Do NOT include units!
Answer:
16.9g of H₂O can be formed
Explanation:
Based on the chemical reaction, 2 moles of H₂ react per mole of O₂. To anser this question we must find limiting reactant converting the mass and volume of each reactant to moles:
Moles H₂ -Molar mass: 2.016g/mol-:
8.76g * (1mol / 2.016g) = 4.345 moles
Moles O₂:
PV = nRT
PV/RT = n
P = 1atm at STP
V = 10.5L
R = 0.082atmL/molK
T = 273.15K at STP
n = 1atm*10.5L / 0.082atmL/molK*273.15K
n = 0.469 moles of oxygen
For a complete reaction of 4.345 moles moles of hydrogen are required:
4.345 moles H2 * (1mol O2 / 2mol H2) = 2.173 moles of O2 are required. As there are just 0.469 moles, Oxygen is limiting reactant
Now, 1 mole of O2 produce 2 moles of H2O. 0.469 moles will produce:
0.469 moles O₂ * (2 moles H₂O / 1mol O₂) = 0.938 moles H₂O.
The mass is -Molar mas H₂O = 18.01g/mol-:
0.938 moles * (18.01g/mol) =
16.9g of H₂O can be formedWhat is the difference between Benedict’s test and Barfoeds test?
Answer:
Benedict's test would determine if the sample is a reducing sugar, and Barfoed's test would determine if it is a monosaccharide or disaccharide.
If a,b,c are in AP & x, y, z are in GP, prove that: x^(b-c).y^(c-a).z^(a- b) = 1
I will report if wrong.
Answer:
b
Explanation:
If 10.00 moles of copper are reacted with 6.00 moles of sulfur according to the following balanced equation, which reactant is the limiter and how many moles of excess reactant would remain after the reaction is completed? 2 Cu + S --> Cu2S
Cu is limiting and 1.00 mole of excess S remain
S is limiting and 1.00 moles of excess Cu remain
S is limiting and 4.00 moles of excess Cu remain
Cu is limiting and 4.00 moles of excess S remain
Answer: Cu is limiting and 1.00 mole of excess S remain
Explanation:
The chemical balanced reaction is:
[tex]2Cu+S\rightarrow Cu_2S[/tex]
According to stoichiometry :
2 moles of [tex]Cu[/tex] require 1 mole of [tex]S[/tex]
Thus 10.00 moles of [tex]Cu[/tex] will require=[tex]\frac{1}{2}\times 10.00=5.00moles[/tex] of [tex]S[/tex]
Thus [tex]Cu[/tex] is the limiting reagent as it limits the formation of product and [tex]S[/tex] is the excess reagent.
Moles of S left = (6.00-5.00) moles = 1.00 mole
Thus Cu is limiting and 1.00 mole of excess S remain.
Oxidation elements of the numbers H2CO2
Which of the following is an base?
OK₂CO₃
ОНЕ
NaCl
NaOH
Answer:
NaOH
Explanation:
NaOH is called base because it dissociates completely in aqueous solution to form hydroxide ion(OH-) and sodium cation (Na+). When it react with an acid , it produce sodium salt and water. It is a strong base because it dissociates completely.
सच्याउंन आधानिक परियोडिक तालिका सफल भयो वा भएन, मूल्याङ्कन गनुहोस्
List out two demerits of Mendeleev's period table. Analyses modern penodic
table is able to overcome these dements or not.
दिदाको तालिका अध्ययन गरी सोधिएका प्रश्नहरुका उत्तर लेख्नुहोस्
Answer:llllIIII
Explanation:
Identify the products formed in this Brønsted-Lowry reaction. HCO−3+HBrO↽−−⇀acid+base
Answer:
[tex]HCO^-_3+HBrO\rightleftharpoons H_2CO_3+BrO^-[/tex]
Explanation:
Hello there!
In this case, according to the Brønsted-Lowry theory of acids, it is possible to realize that HBrO acts as the Brønsted-Lowry acid as it has a free hydrogen to give away to HCO₃⁻ which acts as the Brønsted-Lowry base able to accept the incoming hydrogen; therefore, the Brønsted-Lowry reaction is:
[tex]HCO^-_3+HBrO\rightleftharpoons H_2CO_3+BrO^-[/tex]
Best regards!
In the Brønsted-Lowry reaction between HCO⁻₃ and HBrO, the formed acid is H₂CO₃ and the formed base is BrO⁻.
According to Brønsted-Lowry acid-base theory:
An acid is a substance that donates H⁺.A base is a substance that accepts H⁺.Let's consider the following Brønsted-Lowry reaction.
HCO⁻₃ + HBrO ⇄ acid + base
HBrO can only donate H⁺, so it is an acid.HCO⁻₃ can accept or donate H⁺. Here, it will accept the H⁺ donated by HBrO and behave as a base.The resulting reaction is:
HCO⁻₃ + HBrO ⇄ H₂CO₃ + BrO⁻
H₂CO₃ can donate H⁺ so it is an acid.BrO⁻ can accept H⁺ so it is a base.In the Brønsted-Lowry reaction between HCO⁻₃ and HBrO, the formed acid is H₂CO₃ and the formed base is BrO⁻.
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In the solution containing both 0.10 M acetic acid and 0.10 M sodium acetate, the acetic acid undergoes ionization. The chemical equation for this ionization reaction is the same as for a solution containing acetic acid alone. The difference is that the initial concentration of acetate ion (before any ionization reaction occurs) for the solution containing acetic acid alone is zero, whereas the initial concentration of acetate ion is 0.10 M in your solution containing both acetic acid and sodium acetate. Calculate the percent ionization and the expected initial pH for the solution that contained both 0.10 M acetic acid and 0.10 M sodium acetate. (Hint: Again, you will need to use Ka for acetic acid.)
Answer:
percent ionization = 50.01%; pH = 4.75
Explanation:
To solve this question we must write the acetic acid equilibrium (Where HX will be acetic acid and X⁻ the sodium acetate):
HX(aq) ⇄ H⁺(aq) + X⁻(aq)
Where equilibrium constant, Ka, is defined as:
Ka = 1.76x10⁻⁵ = [H⁺] [X⁻] / [HX]
Where the concentration of each ion is:
[H⁺] = X
[X⁻] = 0.10M + X
[HX] = 0.10M - X
Replacing in Ka expression:
1.76x10⁻⁵ = [X] [0.10-X] / [0.10+X]
1.76x10⁻⁶ + 1.76x10⁻⁵X = 0.10X - X²
X² - 0.0999824 X + 1.76×10⁻⁶ = 0
X ≈ 0.1M → False solution. Decreases a lot the concentration of HX
X = 0.0000176M → Right solution.
The concentration of each ion is:
[H⁺] = 0.0000176062M
[X⁻] = 0.10M + 0.0000176M = 0.1000176M
[HX] = 0.10M - 0.0000176M = 0.0999824M
Percent ionization:
[X-] / [X-] + [HX] * 100 =
0.1000176M / 0.2M =
50.01%And pH = -log [H+]
pH = 4.75As you can see, [H+]≈ Ka
how are electrons arranged in molecules of compounds?
Answer:
electrons are always in the outer shell
When an electron moves, it absorbs or produces energy in the form of photons. Electrons surround the nucleus, which is made up of protons and neutrons, and they all form an atom. The exchange or sharing of electrons between atoms is the main cause of chemical bonding.
Hope this helps you :)
A rectangular block has dimension 20m x10mx5m and mass of 400kg calculate the density of the rectangular block
Answer:
0.4 kg/m^3
Explanation:
v (volume) = 20m x 10m x 5m = 1000 m^3
w (weight) = 400 kg
d (density) = w / v
d = 400 / 1000 = 0.4 kg per cubic meter (kg/m^3)
I apologize if this is a little complex, however all of the math is there, if you're interested then look it over. Otherwise I've provided the answer in the units used for the dimensions and weight provided.
How many atoms of H are in 1 mole of NH3
Answer:
Before you use log you have to multiply the answer of 8.66 mol by 6.02⋅1023 by 3 because the answer of 8.66 mol by 6.02⋅1023 gives you the number of ammonia molecules and in each molecules there are 3 hydrogen atoms present.
Explanation:
Calculate the pH and pOH of 500.0 mL of a phosphate solution that is 0.285 M HPO42– and 0.285 M PO43–. (Ka for HPO42- = 4.2x10-13 at 25°C)
Answer: when concentrations of acid and base are same, pH = pKa
PH = 12.38 pOH = 1.62
Explanation: pKa= -log(Ka)= 12.38. PH + pOH = 14.00
The pH of the solution is 12.38 and the pOH of the solution is 1.62.
Using the Henderson Hasselbalch equation;
pH = pKa + log [A-]/[HA]
Where;
pKa = - log Ka = -log[ 4.2x10-13] = 12.38
[A-] = [PO43–] = 0.285 M
[HA] = [HPO42-] = 0.285 M
Substituting values;
pH = 12.38 + [ 0.285 M]/[ 0.285 M]
pH = 12.38
But;
pH + pOH = 14
pOH = 14 - 12.38
pOH = 1.62
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What is the purpose of replication?
1-to make an RNA template from DNA
2-to produce copies of a DNA molecule
3-to move mRNA through the ribosome
4-to change the number, type, or order of bases in DNA
Answer:
2-to produce copies of a DNA molecule
what part of of the universe is less than 1 km in diameter
Answer:
Meteoroids
Explanation:
Meteoroids are the elements of the universe that have the smallest diameter among all elements, reaching less than 1 km in diameter. They are any rocky or metallic body, which exists in space and does not reach more than 100 meters. It is common for meteoroids to fall to earth, but their impact is not as destructive as the impact of other space bodies, due to their tiny size.
Match the lettered empty blanks in the following statements to the correct word that makes each statement true. When a compound dissolves in water to produce an aqueous solution, the compound is said to be Blank A in water. If an aqueous solution conducts electricity, then the solute is called a(n) Blank B. Group of answer choices Blank A [ Choose ] Blank B electrolyte
Answer:
1. Soluble.
2. Electrolyte.
Explanation:
Solubility is a term used to describe how readily a substance can be dissolved in a solvent to form a solution. Thus, a substance is said to be soluble if it dissolves completely in a solvent and insoluble if it doesn't dissolve or only dissolves partially.
For example, sodium chloride (NaCl) when mixed with water dissociates into sodium and chloride ions. Thus, salt (sodium chloride) is said to be soluble because it dissolves completely in water.
In Chemistry, dissolution can be defined as the process of dissolving or dissociating a solute in solid, liquid or gaseous phase into fragmented particles by a solvent in order to form a solution. For dissolution to occur in solids, the crystalline structure of the substance must be broken up so as to release ions, atoms or molecules to produce a solution. For liquid and gases, the substance to be dissolved must form a non-covalent bond with the solvent to produce a solution.
Hence, a compound that dissolves in water to produce an aqueous solution is said to be soluble in water. Also, the solute of an aqueous solution that conducts electricity is called an electrolyte.
A car accelerates away from the starting line at 3.6 m/s2 and has the mass of 2400 kg. What is the net force acting on the vehicle?
Answer:
F = m x a
F = 2400 kg x 3.6 m/s2
F = 8,640 N
Explanation:
Brainliest will be given to correct answer :)
Chemistry II Help please! Last question on my homework and I'm stuck.
Thank you!
Answer: [tex]\Delta G[/tex] for the reaction is -90kJ
Explanation:
The balanced chemical reaction is,
[tex]2H_2S(g)+SO_2(g)\rightarrow 3S_{rhombic}(s)+2H_2O(g)[/tex]
The expression for Gibbs free energy change is,
[tex]\Delta G=[n\times G_{products}]-[n\times G_{reactants}][/tex]
Putting the values we get :
[tex]\Delta G=[3\times G_f{S,rhombic}+2\times G_f{H_2O}]-[2\times G_f{H_2S}+1\times G_f{SO_2}][/tex]
[tex]\Delta G=[(3\times 0kJ/mol)+(2\times -229kJ/mol)]-[(2\times -34kJ/mol) +(1\times -300kJ/mol)][/tex]
[tex]\Delta G=-90kJ[/tex]
Thus [tex]\Delta G[/tex] for the reaction[tex]2H_2S(g)+SO_2(g)\rightarrow 3S_{rhombic}(s)+2H_2O(g)[/tex] is -90kJ
If an element has 6 protons and its mass number is 14, how many neutrons and electrons does it have?
Answer:
8 neutrons and 6 electrons
Explanation:
Mass number= neutrons + protons
14=x+6
x=14-6
x=8
protons=electrons
6 protons=6 electrons
A common ancestor is an organism that is the
O direct ancestor of two or more different organisms
O direct ancestor of one organism.
O indirect ancestor of two or more different organisms.
O indirect ancestor of one organism.
A common ancestor is an organism that is the direct ancestor of two or more different organisms.
A common ancestor refers to an organism that is shared by multiple organisms, serving as the direct predecessor to those organisms. It is the point in evolutionary history where two or more distinct lineages diverged from a single ancestral lineage. This means that the common ancestor is the starting point from which different species or groups of organisms evolved over time.
In the context of evolution, organisms share common ancestry due to the process of descent with modification. Through genetic inheritance and gradual changes in traits over generations, new species arise from a common ancestor. As these species undergo divergent evolution, they develop distinct characteristics and adaptations, eventually becoming separate lineages.
Hence, the correct option is the direct ancestor of two or more different organisms.
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The pressure of a sample of dry air is held constant 2.25 atm while the temperature is
decreased from 100°C to 7.0°C. The original volume of the sample is 43 L. Which of
the following is closest to the final volume of the sample?
A) 3.0L
B) 32L
C) 57 L
D) 610 L
The pressure of a sample of dry air is held constant 2.25 atm while the temperature is decreased from 100°C to 7.0°C. The original volume of the sample is 43 L. 32 L is the closest to the final volume of the sample?
What is Charles's law?A law states that the volume of an ideal gas at constant pressure is directly proportional to the absolute temperature.
Charles’ law:
[tex]\frac{V_1}{T_1}[/tex] = [tex]\frac{V_2}{T_2}[/tex]
The volume and temperature of a fixed amount of gas at a constant pressure are directly proportional.
To use the equation, the temperature must be in Kelvin.
[tex]V_2[/tex] = [tex]\frac{V_1}{T_1} XT_2[/tex]
[tex]V_2[/tex] = 32 L
[tex]V_2[/tex]= 32 L
Hence, the correct answer is B.
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What is the molarity of a 5 L solution that contains 7.5 moles of NaOH?
A. O 1500 M
В.
1.5 M
C
0.017M
D. O 0.015 M
The molarity of the solution will be:
B. 1.5 M, this can be calculated on adding the values of V and n in molarity formula.
What is Molarity?It is defined as the ratio of number of moles of solute by the Volume of the solution in liters.
It is given by:
Molarity = n/ V
What information do we have?
Volume = 5L
Moles of NaOH = 7.5 moles
On substituting the values
M= n/V
M= 7.5 moles / 5L
M= 1.5 M
Thus, the molarity of the solution is 1.5 M.
Hence, option B is correct.
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How many liters of nitrogen gas (N₂) are required to produce 7.5 x 10²⁶ molec NH₃ gas with excess of hydrogen gas at STP?
Answer: The volume of nitrogen gas that is required is 13944 L.
Explanation:
Given values:
Number of molecules of ammonia gas = [tex]7.5\times 10^{26}[/tex]
According to the mole concept:
[tex]6.022\times 10^{23}[/tex] number of molecules are present in 1 mole of a compound
So, [tex]7.5\times 10^{26}[/tex] number of molecules will be present in [tex]\frac{1}{6.022\times 10^{23}}\times 7.5\times 10^{26}=1.245\times 10^3 moles[/tex] of ammonia gas
The chemical equation for the formation of ammonia gas follows:
[tex]N_2 (g) + 3H_2(g) \rightarrow 2NH_3(g)[/tex]
According to the stoichiometry of the reaction:
2 moles of ammonia gas are produced from 1 mole of nitrogen gas
So, [tex]1.245\times 10^3[/tex] moles of ammonia gas will be produced from [tex]\frac{1}{2}\times 1.245 \times 10^3=6.225\times 10^2[/tex] moles of nitrogen gas
At STP conditions:
1 mole of a gas occupies 22.4 L of volume
So, [tex]6.225 \times 10^2[/tex] moles of nitrogen gas will occupy [tex]\frac{22.4 L}{1 mol}\times 6.225\times 10^2 moles=13944 L[/tex] of volume
Hence, the volume of nitrogen gas that is required is 13944 L.
Sally has constructed a concentration cell to measure Ksp for MCln. She constructs the cell by adding 2 mL of 0.05 M M(NO3)n to one compartment of the microwell plate. She then makes a solution of MCln by adding KCl to M(NO3)n. She adds 6.380 mL of the resulting mixture to a second compartment of the microwell plate.
Sally knows n (the charge on the metal ion) = +2
She has already calculated [Mn+] in the prepared MCln solution using the Nernst equation. [Mn+] = 8.279 M
Required:
How many moles of [Cl-] must be dissolved in that compartment?
Answer:
0.1056 mole
Explanation:
As Sally knows that the charge on the metal ion is n = +2
[tex]$MCl_n=MCl_2$[/tex]
In that compartment [tex]$[M^{n+}]=[m^{2+}]=8.279 \ M$[/tex]
The volume of the [tex]$MCl_n$[/tex] taken in that compartment = 6.380 mL
So, the number of moles of [tex]$M^{2+} = 8.279 \times 6.380$[/tex]
= 52.82 m mol
= 0.05280 mol
[tex]$MCl_n \rightarrow M^{n+}+nCl^-$[/tex]
But n = 2
Therefore, moles of [tex]$Cl^-$[/tex] = 2 x moles of [tex]$M^{n+}$[/tex]
= 2 x 0.05282
= 0.1056 mole
What is the total number of electrons in the valence shell of an atom of aluminum in the ground
state?
1)8 2)2 3)3 4)10
Answer:
This is a total of ten electrons in filled shells
Explanation:
3. Jordan built a model of a neutral helium atom.
Nucleus
Proton
Neutron
Electron
What change would fix the mistake in Jordan's model?
X^2/3-5X^1/3+6=0
find x
Answer:
[tex]x=27,8[/tex]
Explanation:
The equation is
[tex]x^{\dfrac{2}{3}}-5x^{\dfrac{1}{3}}+6=0[/tex]
Let,
[tex]x^{\dfrac{1}{3}}=y[/tex]
So,
[tex]y^2-5y+6=0\\\Rightarrow y=\dfrac{-\left(-5\right)\pm \sqrt{\left(-5\right)^2-4\times 1\times 6}}{2\times 1}\\\Rightarrow y=3,2[/tex]
[tex]x^{\dfrac{1}{3}}=y\\\Rightarrow y^3=x\\\Rightarrow x=3^3\\\Rightarrow x=27[/tex]
[tex]x=2^3\\\Rightarrow x=8[/tex]
Hence, [tex]x=27,8[/tex].
In addition to Earth, many of the other planets in the Solar System have atmospheres.
O True
O False
the answer is True.
each planet has a significant atmosphere
Answer:
True
Explanation:
bc i know
What is the pH of 0.42M aniline?
Answer:
Kb=x^2/0.42-x (eqn to calculate)
basicity (pkb) 9.3
Explanation:
Identify the kind(s) of intermolecular forces that would occur between the solute and solvent in an acetic acid (which is polar and contains an OHOH group) solution. Check all that apply. Check all that apply. dispersion hydrogen bonding ion-dipole dipole-dipole
Explanation:
The acetic acid is a polar compound. The polar molecules have a positive and negative extreme for this reason they are dipoles. The dipoles can attract other dipoles or ions. So, it can establish ion-dipole and dipole-dipole forces with the solute. In addition, acetic acid has a hydroxyl group that can interact with hydrogens or other very electronegative atoms (oxygen, nitrogen and fluor) forming hydrogen bridge junctions.