Answer:
(A) 0.4M NaOH
Explanation:
The 20M NaOH caustic soda is diluted from 10mL to 500mL, that is:
500mL / 10mL = Is diluted 50 times.
That means we can solve the new concentration of the diluted solution dividing the stock concentration (20M) 50 times:
20M / 50 = 0.4M NaOH is the concentration of the diluted NaOH solution.
Right answer is:
(A) 0.4M NaOHCan someone answer 3’for me please?
The combustion of ethyne, shown below unbalance, produces heat which can be used to weld metals:
C2H2 (g) +502 (g) →2CO: (g) +H20 (g) AH reaction= -1544kJ
How much ethyne gas (in g) would you need to react with excess oxygen according to this reaction in order to raise the temperature of 325 g of high carbon steel from 165'C to its melting point, 1540 C? The heat capacity of high carbon steel is 0.490 J/g'C. (Assume a complete reaction and that all heat is transferred from the reaction to the metal with no loss.)
a. 7.37g
b. 1.84 g
c. 4.13 g
d 3.69 g
Answer:
3.69 g
Explanation:
Given that:
The mass m = 325 g
The change in temperature ΔT = ( 1540 - 165)° C
= 1375 ° C
Heat capacity [tex]c_p[/tex] = 0.490 J/g°C
The amount of heat required:
q = mcΔT
q = 325 × 0.490 × 1375
q = 218968.75 J
q = 218.97 kJ
The equation for the reaction is expressed as:
[tex]C_2H_{2(g)} + 5O_{2(g)} \to 2CO_{2(g)} + H_2O_{(g)} \ \ \ \ \ \Delta H^o_{reaction} = -1544 \ kJ[/tex]
Then,
1 mole of the ethyne is equal to 26 g of ethyne required for 1544 kJ heat.
Thus, for 218.97 kJ, the amount of ethyne gas required will be:
[tex]= \dfrac{26 \ g}{1544 \ kJ} \times 218.97 \ kJ[/tex]
= 3.69 g
During homogeneous catalysis, if a catalyst is present in the liquid phase, which phase must the reactants be in?
Answer:
The reactants must be in the liquid phase.
Explanation:
Homogeneous means that something is of the same nature.
In the context of catalysis, it means that the catalyst and the reactants are in the same phase.
If the catalyst is in the solid phase, the reactants are solids are well.
If the catalyst is in the liquid phase, then the reactants are also in the liquid phase.
And so on.
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What is a main difference between a mixture and a pure substance?
OAmixture is only a liquid, but a pure substance can be in any state.
OAmixture looks the same throughout, but a pure substance does not.
OAmixture can vary in composition, but a pure substance has a set composition.
O Amixture can be made up of a single compound, but a pure substance cannot
Answer:
I think the answer is c!
Explanation:
Pure substances are further broken down into elements and compounds. Mixtures are physically combined structures that can be separated into their original components. A chemical substance is composed of one type of atom or molecule. hope this helps you!
Write the net ionic equation for Potassium chloride + sodium nitrate
I believe the answer is this:
KCl + NaNO3 --> KNO3 + NaCl.
Answer:
No reaction
Explanation:
KCl + NaNO3 --> KNO3 + NaCl
Since these substances are all aqueous (no precipitates or other phases involved), if you were to write the ionic equation and cross out spectators, they'd all cancel so there is no reaction.
The electron configuration for an element is 1s2 2s2 2p6 3s2 3p6. What is the atomic number of the element? *
A. 3
B. 11
C. 18
D. 22
Explanation:
Electronic configuration =
1s² 2s² 2p⁶ 3s² 3p⁶
Atomic number = 18Element = ArgonSymbol = ArGroup = 18period = 3Therefore,
Option C is correct✔
According to the electronic configuration, the atomic number of the element is 18.
What is electronic configuration?Electronic configuration is defined as the distribution of electrons which are present in an atom or molecule in atomic or molecular orbitals.It describes how each electron moves independently in an orbital.
Knowledge of electronic configuration is necessary for understanding the structure of periodic table.It helps in understanding the chemical properties of elements.
Elements undergo chemical reactions in order to achieve stability. Main group elements obey the octet rule in their electronic configuration while the transition elements follow the 18 electron rule. Noble elements have valence shell complete in ground state and hence are said to be stable.
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The red outlined elements have what major characteristics in common?
1 point
Metals, Nonmetals, and Metalloids
One major characteristic they have in common is they are metals.
Which model of the solar system is shown here?
Answer: C
Explanation: hope this helps
The model of the solar system that is shown here is:
C. Geometric model
Model for description of earth and other entites
Geometric model:In astronomy, the geocentric model is a superseded description of the Universe with Earth at the center. Under the geocentric model, the Sun, Moon, stars, and planets all orbit Earth.
Characteristics:
the Earth is the focal point of the universe and it is fixed,the planets, the Sun, and the stars spin around the Earth,the circle and the circle are "awesome" shapes, so all movements overhead ought to follow roundabout ways, which can be credited to objects being appended to circular shells.Thus, option C is correct.
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If 27.3% of a sample of silver-112 decays in 1.52 hours, what is the half-life (in hours to 3 decimal places)?
Answer: The half life of the sample of silver-112 is 3.303 hours.
Explanation:
All radioactive decay processes undergoes first order reaction.
To calculate the rate constant for first order reaction, we use the integrated rate law equation for first order, which is:
[tex]k=\frac{2.303}{t}\log \frac{[A_o]}{[A]}[/tex]
where,
k = rate constant = ?
t = time taken = 1.52 hrs
[tex][A_o][/tex] = Initial concentration of reactant = 100 g
[A] = Concentration of reactant left after time 't' = [100 - 27.3] = 72.7 g
Putting values in above equation, we get:
[tex]k=\frac{2.303}{1.52hrs}\log \frac{100}{72.7}\\\\k= 0.2098hr^{-1}[/tex]
To calculate the half life period of first order reaction, we use the equation:
[tex]t_{1/2}=\frac{0.693}{k}[/tex]
where,
[tex]t_{1/2}[/tex] = half life period of first order reaction = ?
k = rate constant = [tex]0.2098hr^{-1}[/tex]
Putting values in above equation, we get:
[tex]t_{1/2}=\frac{0.693}{0.2098hr^{-1}}\\\\t_{1/2}=3.303hrs[/tex]
Hence, the half life of the sample of silver-112 is 3.303 hours.
Which scenario is likely to result in the most diverse offspring?
1 point
Sexual reproduction between two individuals from different continents
Sexual reproduction between two individuals in the same population
Asexual reproduction by binary fission
Asexual reproduction by budding
Answer: i think it is binary fission
Explanation:
c. What might have happened in Kush and Egypt if Kush had developed iron
weapons?
Answer:
Kush would have been able to fight better and probably would have never been invaded by Egypt, and they could have beaten the Assyrians when they tried to takeover Egypt. And the 25th dynasty would have continued.
Explanation:
that is my explanation and answer^
Electron transfer between redox centers in proteins is controlled by quantum tunneling. We can model the region between two redox centers as an energy barrier which the electron must cross. If the distance between the redox centers is 0.681 nm and the energy of the electron is 0.5540.554eV lower than the height of the barrier, what is the probability that the electron will successfully cross to the next redox center
Answer:
5.61 e⁻³
Explanation:
Given that:
The barrier length = 0.681 nm = 6.81 × 10⁻¹⁰
The difference between the height of the barrier & the energy of the electron is;
[tex]V - E = 0.554 \ eV (1.6 \times 10^{-19} )[/tex]
= 8.864 × 10⁻²⁰ V
where;
m = 9.1 × 10⁻³¹ kg
The probability[tex]P = e^{-2 \ kd}[/tex]
[tex]k = 2 \pi \sqrt{\dfrac{2m (V-E)}{h^2} }[/tex]
[tex]k = 2 \pi \times \dfrac{\sqrt{2 \times 9.1 \times 10^{-31} \times 8.864 \times 10^{-20}}}{6.63 \times 10^{-34}}[/tex]
k = 3.806 × 10⁹
[tex]P = e^{-2 \ kd}[/tex]
[tex]P = e^{2 \times 3.806 \times 10^9 \times 6.81 \times 10^{-10}}[/tex]
P = 0.005606
P = 5.61 × 10⁻³
P = 5.61 e⁻³
The only sure evidence for a chemical reaction is
Answer:
that one or more new substances are produced. Temperature Changes Chemical reactions can release energy or absorb energy.
Explanation: .
A molecule has a molar mass of 22.45 g/mol. What is the mass of 4.12*10^24 of the molecules?
Answer:
153.56g
Explanation:
Number of moles = mass/molar mass
To get the number of moles of the molecule, we divide the number of molecules contained by Avagadro's number, which is 6.02 × 10^23 molecules.
moles = 4.12 × 10^24 ÷ 6.02 × 10^23
number of moles = 0.684 × 10^(24-23)
number of moles = 0.684 × 10^(1)
number of moles = 6.84mol
If the molar mass of the molecule is 22.45 g/mol, the mass of the molecule can be calculated thus:
mass = moles × molar mass (MM)
mass = 6.84 × 22.45
mass = 153.558
mass = 153.56g
The list identifies various properties of four elements:
Element 1 is a gas at room temperature.
Element 2 is a solid which conducts electricity.
Element 3 is a gas with an effective nuclear charge of +7.
Element 4 is malleable and can take the form of a shiny solid sheet.
Based on this list, which elements are metals?
A. Elements 1 and 3
B. Elements 1 and 4
C. Elements 2 and 3
D. Elements 2 and 4
Answer: D
Explanation: I guessed it and got it right
A fundamental object that is difficult to divide into smaller bits is known as an element. Therefore option D is correct.
What is element ?An element is a species of atoms, including the pure material made entirely of that species, that have a specific number of protons in their nuclei. Chemical elements, in contrast to chemical compounds, cannot be reduced by any chemical process into simpler molecules.
An element is a material that cannot be broken down by non-nuclear processes in chemistry and physics. A discrete component of a larger system or collection is referred to as an element in computers and mathematics.
Metals, nonmetals, and metalloids are the Periodic Table's three main groupings. Each group's constituent elements share comparable physical and chemical characteristics. Among the physical characteristics used to separate the three groups are, A substance's capacity to reflect light is referred to as luster.
Thus, option D is correct.
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What is electron affinity?
Answer:
The ability of an atom to accept an electron.
Explanation:
Electron affinity is measured by observing the energy change of a substance when an electron is added to it in its neutral gas form. For example, elements that are on the far right of the periodic table (excluding noble gases) are more likely to accept electrons rather than give them up. This is why Fluorine has the highest electron affinity of all atoms on the periodic table.
for the following equation to be bal
Answer:
What's the rest of the question
Explanation:
How many moles are in the 100,000g of CuSO4 • 5H2O ?
Answer:
try (107.87 amu)
Explanation:
At what temperature is water a gas
Answer:
212 degrees Fahrenheit
Explanation:
When liquid water reaches a low enough temperature, it freezes and becomes a solid—ice. When solid water is exposed to enough heat, it will melt and return to a liquid. As that liquid water is further heated, it evaporates and becomes a gas—water vapor.
What is the scale called that measures the strength of an acid or base in solution?
A the Color scale
B pH scale
C The litmus test
D The number scale
Answer:
The answer is B. pH scale
Answer:
pH scale
Explanation:
ph scale basically measures the acidity and basicity of the solution
Which is stronger, the strong force (SF) or the electromagnetic force (EMF)? Describe how they battle each other in the nucleus. What would happen if their strengths were reversed?
Answer:uclear Force that holds together the nucleus of an atom. electromagnetic force. ... They are unstable because the Strong Force that would hold them together if the protons and neutrons were closer is weakened because the protons and neutrons get too far apart.
Explanation:
A metal is found that has a mass of 27g and will displace 6mL of water. Calculate its density and identify the metal.
The density of metal = 4.5 g/ml, and the metal = Titanium
Further explanationDensity is a quantity derived from the mass and volume
Density is the ratio of mass per unit volume
Density formula:
[tex]\large {\boxed {\bold {\rho ~ = ~ \frac {m} {V}}}}[/tex]
ρ = density
m = mass
v = volume
mass of metal=27 g
volume = 6 ml
The density :
[tex]\tt \rho=\dfrac{27}{6}\\\\\rho=4.5~g/ml[/tex]
The metal with a density of 4.5 g/ml is Titanium
How many atoms are in 2.37 moles of Krypton
Answer:
1.43 × 10²⁴ atoms Kr
General Formulas and Concepts:
Chemistry - Atomic Structure
Using Dimensional AnalysisAvogadro's Number - 6.022 × 10²³ atoms, molecules, formula units, etc.Explanation:
Step 1: Define
2.37 mol Kr
Step 2: Convert
[tex]2.37 \ mol \ Kr(\frac{6.022 \cdot 10^{23} \ atoms \ Kr}{1 \ mol \ Kr} )[/tex] = 1.42721 × 10²⁴ atoms Kr
Step 3: Check
We are given 3 sig figs. Follow sig fig rules and round.
1.42721 × 10²⁴ atoms Kr ≈ 1.43 × 10²⁴ atoms Kr
How high of a Frequency would a photon have to be for it to have an energy of 4 joules
The frequency of photon=6.03 x 10³³ /s
Further explanationRadiation energy is absorbed by photons
The energy in one photon can be formulated as
[tex]\large{\boxed{\bold{E\:=\:h\:.\:f}}}[/tex]
Where
h = Planck's constant (6,626.10⁻³⁴ Js)
f = Frequency of electromagnetic waves
Energy of photon = 4 J
So the frequency :
[tex]\tt f=\dfrac{E}{h}\\\\f=\dfrac{4}{6.626.10^{-34}}\\\\f=6.03.10^{33}/s[/tex]
What is the molarity of a NaOH solution if 28.2 mL of a 0.355 M H2SO4 solution is required to neutralize a 25.0-mL sample of the NaOH solution?A) 0.801B) 0.315C) 0.629D) 125E) 0.400
Answer:
A) 0.801
Explanation:
The reaction that takes place is:
2NaOH + H₂SO₄ → Na₂SO₄ + 2H₂OFirst we calculate the H₂SO₄ moles that reacted:
0.355 M * 28.2 mL = 10.011 mmol H₂SO₄Now we convert H₂SO₄ moles to NaOH moles:
10.011 mmol H₂SO₄ * [tex]\frac{2mmolNaOH}{1mmolH_2SO_4}[/tex] = 20.022 mmol NaOHFinally we calculate the molarity of the NaOH solution:
20.022 mmol NaOH / 25.0 mL = 0.801 MSo the answer is option A.
The molarity of the NaOH solution used in the neutralization reaction has been 0.801 [tex]\rm \times\;10^-^3[/tex] M. Thus, option A is correct.
The neutralization reaction has resulted in the formation of the salt and water on reacting an acid with a base. In the neutralization reaction, the strength of acid and base can be given as:
[tex]\rm 2\;NaOH\;+\;H_2SO_4\;\rightarrow\;Na_2SO_4\;+\;H_2O[/tex]
For the neutralization of 1 mole of sulfuric acid, 2 moles of NaOH has been required.
The moles of sulfuric acid can be given as:
Moles = Molarity × Volume
Given, the molarity of acid ([tex]\rm H_2SO_4[/tex]) = 0.355 M
Volume of acid = 28.2 ml = 0.0282 L
Volume of base (NaOH) = 25 ml = 0.025 L
Moles of [tex]\rm H_2SO_4[/tex] = 0.355 × 0.0282 mol
Moles of [tex]\rm H_2SO_4[/tex] = 10.011 mol.
Since, 1 mole [tex]\rm H_2SO_4[/tex] = 2 moles NaOH
10.011 moles [tex]\rm H_2SO_4[/tex] = 10.011 × 2 moles NaOH
10.011 moles [tex]\rm H_2SO_4[/tex] = 20.022 moles NaOH.
The neutralization of 0.355 M [tex]\rm H_2SO_4[/tex] requires 20.022 moles NaOH. The strength of the NaOH solution will be:
Molarity = [tex]\rm \dfrac{Moles}{Volume\;(L)}[/tex]
Molarity of NaOH = [tex]\rm \dfrac{20.022}{0.025}[/tex]
Molarity of NaOH = 0.801 [tex]\rm \times\;10^-^3[/tex] M.
The molarity of the NaOH solution used in the neutralization reaction has been 0.801 [tex]\rm \times\;10^-^3[/tex] M. Thus, option A is correct.
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Which of the following transitions produces light with the longest wavelength?
A. 2—>1
B. 3—>1
C. 4—>2
D. 4—>3
g Which statement concerning the structure of the atom is correct? Protons and neutrons have most of the mass and occupy most of the volume of the atom. Electrons have most of the mass but occupy very little of the volume of the atom. Electrons have most of the mass and occupy most of the volume of the atom. Protons and neutrons have most of the mass but occupy very little of the volume of the atom.
Protons and neutrons have most of the mass but occupy very little of the volume of the atom.
The statement concerning the structure of the atom is correct is Protons and neutrons have most of the mass but occupy very little of the volume of the atom. Therefore, option D is correct.
What is an atom ?Each atom is made up of a nucleus and one or more electrons that are linked to it. One or more protons and a significant number of neutrons make up the nucleus. Only the most prevalent type of hydrogen is neutron-free. Atoms that are neutral or ionized make up every solid, liquid, gas, and form of plasma.
But when it comes to the name atom, we must travel back to 400 B.C. ancient Greece. The Greek word atomos, which meaning "uncuttable," was proposed by Democritus, a renowned philosopher. In the end, all matter could be reduced to distinct, tiny particles, or atomos, he said.
The smallest unit of matter that may be divided without producing electrically charged particles is the atom.
Thus, option D is correct.
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Can someone answer 4 for me please?
A student makes observations of a tree in a nearby forest. Which of the following observations of the
tree's characteristics would be useful in determining its identity with a dichotomous key?
A
It contains the nests of several birds.
B
Its leaves are long and narrow.
с
Its branches were recently cut.
D
It provides shade for ground brush.
The observations of the tree's characteristics would be useful in determining its identity with a dichotomous key is its leaves are long and narrow. The correct option is B.
What is an observation?Observation is a process of recognizing and recording an event or fact that frequently involves measuring it with tools. Recognizing and recording an event, or fact frequently involves measuring with tools. Field notes are written observations made while participating in field observations or immediately afterward.
They are crucial for understanding phenomena that have been seen in the field. Field notes frequently take the form of scratch notes, diaries, and notebooks. In the scientific field, observation is a crucial step.
Therefore, the correct option is B. Its leaves are long and narrow.
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Calculate the molar mass of Ga(NO3)3
255.732 g/mol
159.738 g/mol
227.718 g/mol
131.727 g/mol
Answer:
255.732 g/mol
Explanation:
Molar mass of Ga(NO3)3 = 255.7322 g/mol. This compound is also known as Gallium(III) Nitrate.