Answer:
Acidic solution used to clean a crucible
Explanation:
This liquid dissolves alcoholic solvents such as crucible, that is why it was selected as the ideal for cleaning.
Although it would be ideal to know in detail which chemical compound is the one you want to clean so that the cleaning technique has better effectiveness.
WASTE CONTAINER refers to the solvent used to rinse chemicals out of a beaker, and it also refers to the acid solution used to clean a crucible. Water used to rinse the detergent out of a flask refer to the SINK.
The disposal containers in a lab can be used for recycling, disposal of trash, glassware disposal box, sharp box, etc.A waste container is a container usually used to dispose of waste in a laboratory, which may be made of plastic.Moreover, a laboratory sink can be used to wash tools and/or hands without the hazard of damaging the health or the sink.In conclusion, WASTE CONTAINER refers to the solvent used to rinse chemicals out of a beaker, and it also refers to the acid solution used to clean a crucible. Water used to rinse the detergent out of a flask refer to the SINK.
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What is the oxidation number of calcium
Answer:
0 for the elemental form, +2 in its compounds.
How many moles of sodium are present in 17 g of Na?
What is the number of moles in 60g of Na2SO4?
How many moles are there in 93.5g of CO2?
How many moles are there in 25.6g of Sodium Nitrate?
Determine the number of particles in .75 mol of calcium hydroxide
Answer:
1. 0.74mol
2. 0.42mol
3. 2.125mol
4. 0.301mol
5. 4.52 × 10^23 particles
Explanation:
Number of moles (n) in a substance can be found using the formula:
mole (n) = mass/molar mass
Using this formula, the following moles are calculated:
1. Molar of Na = 23g/mol
mole = 17/23
mole = 0.74mol
2. Molar mass of Na2SO4 = 23(2) + 32 + 16(4)
= 46 + 32 + 64
= 142g/mol
Mole = 60/142
mole = 0.42mol
3. Molar mass of CO2 = 12 + 16(2)
= 12 + 32
= 44g/mol
mole = 93.5/44
mole = 2.125mol
4. Molar mass of sodium nitrate (NaNO3) = 23 + 14 + 16(3)
= 23 + 14 + 48
= 85g/mol
mole = 25.6/85
mole = 0.301mol
5. Number of particles in one mole of a substance is 6.022 × 10^23 particles. Hence, in 0.75mol of calcium hydroxide (Ca(OH)2, there will be;
0.75mol × 6.02 × 10^23
= 4.515 × 10^23
= 4.52 × 10^23 particles
The balanced equation for the production of sugars by photosynthesis is shown below.
This equation demonstrates the law of conservation of mass because
A.
there are more oxygen atoms on the right side of the equation than on the left.
B.
there is the same number of compounds on the right side of the equation as the left.
C.
there is the same number of each type of atom on the right side of the equation as the left.
D.
the sugar molecule on the right has the same mass as the carbon dioxide molecules on the left.
Answer:
Black
Explanation:
Answer:
the answer is
-there is the same number of each type of atom on the right side of the equation as the left.
Explanation:
i have study island too :')
what is the difference between test tube and boiling tube
Test tubes heat small amounts of liquids while boiling tube boils liquids
3.4 x 10-25 kg = ? microounces
Answer: 1.2 x 10^-17 microounces
Explanation:
Ounce = 28.5G microounce = 28.5*10^-6g
3.4*10^-25 kg = 3.4*10^-22 g = (3.4/2.85)*10^(-22+5) = 1.2*10-17
At 25.0°C the Henry's Law constant for dinitrogen monoxide (N2O) gas in water is 0.025 M/atm.
Calculate the mass in grams of N2O gas that can be dissolved in 325. mL of water at 25.0°C and a N2O partial pressure of 0.69 atm.
Be sure your answer has the correct number of significant digits.
Answer:
The mass in grams of N₂O gas that can be dissolved is 0.18 g
Explanation:
The solubility of a gas is proportional to the partial pressure of that gas, over a determined solvent. That's what Henry's law states. We see the formula:
S = K . Pp
Where S is solubility and K is Henry's constant. This specific for each gas and each temperature, while Pp means partial pressure.
We replace data:
S = 0.025 M/atm . 0.69atm
S = 0.01725 M
This is the solubility of the gas, so now, we need to know what mass of gas is solubilized. We convert the moles, with the volume of water.
0.01725 mol/L . 0.235 L = 4.05×10⁻³ moles
Now, we determine the mass in grams: 4.05×10⁻³ mol . 28 g / 1mol =
0.1782 g
which statements best describe measuring with a graduated cylinder?
Consider the addition of an electron to the following atoms from the fifth period. Rank the atoms in order from the most negative to the least negative electron affinity values based on their electron configurations.
Atom or ion Electron configuration
I [Kr]4d105s25p5
Sn [Kr]4d105s25p2
Xe [Kr]4d105s25p6
Rank the electron affinity from most negative to least negative. To rank items as equivalent, overlap them.
Answer:
I>Sn>Xe
Explanation:
Electron affinity refers to the ability of an atom to accept electron(s) and form a negative ion.
We know that electron affinity is a periodic trend that increases across the period but decreases down the group.
Hence the, electron affinity of iodine is far higher than that of tin. However, xenon is a noble gas and does not accept electrons. Hence, it has an electron affinity of 0 KJ/mol.
Where and in what features is water found on Earth?
Answer: On Earth, liquid water exists on the surface in the form of oceans, lakes and rivers. It also exists below ground as groundwater, in wells and aquifers. Water vapor is most visible as clouds and fog. The frozen part of Earth's hydrosphere is made of ice: glaciers, ice caps and icebergs.
Write a mechanism for the esterification of propanoic acid with 18O-labeled ethanol. Show clearly the fate of the 18O label. (b) Acid-catalyzed hydrolysis of an unlabeled ester with 18O-labeled water (H218O) leads to incorporation of some 18O into both oxygens of the carboxylic acid product. Explain by a mechanism. (Hint: You must use the fact that all steps in the mechanism are reversible.)
Answer:
See explanation and images attached
Explanation:
a) In the mechanism for the acid catalysed esterification of propanoic acid using ethanol, we can see that the first step is the protonation of the acid followed by nucleophillic attack of the alcohol. Loss of water and consequent deprotonation regenerates the acid catalyst. We can see the fate of the 18O labelled ethanol in the mechanism shown.
b) In the second mechanism, an unnamed ester is hydrolysed using an acid catalyst. The attack of the acid and subsequent nucleophillic attack of water labelled with 18O leads to the incorporation of this 18O into the product acid as shown in the mechanism attached to this answer.
Re-order each list in the table below, if necessary, so that the atoms or ions in it are listed in order of decreasing size.
atoms or lons:
•Be, Be^+, Li
•Br, I, Cl
•Cl, Na, S
atoms or lons in order
of decreasing size
Answer: Na, S, Cl
Explanation:
Atomic size decreases as one moves from left to right on the periodic table with elements in the same period. This is as a result of the electrons increasing in the outer circle and thus being drawn to the protons in the nucleus which will lead to the outer shell area decreasing.
Sodium (Na) comes before Sulfur (S) which comes before Chlorine (S) so this is the decreasing order as they are all in the same period.
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100 POINTS FOR BEST ANSWER! What is the difference between LDOF and SDOF
An SDOF system is one whose motion is governed by a single, second-order differential equation. Only two variables, position and velocity are needed to describe the trajectory of the system. Many structures can be idealized as single degree-of-freedom systems.
The LDAP Data Interchange Format is a standard plain text data interchange format for representing LDAP directory content and update requests. LDIF conveys directory content as a set of records, one record for each object.
A particle that travels around the nucleus of an atom in orbitals is called a(n)
Answer: electrons
Explanation:
Answer: It is called an electron because it is attracted to the positively charged particales called protons in the center of the atom.
Explanation:
In the reaction 2 HgO --> 2 Hg + O2
how many moles of O2 are produced when 5 moles of HgO are decomposed?
Answer:
2.5 moles of oxygen are produced.
Explanation:
Given data:
Number of moles of O₂ produced = ?
Number of moles of HgO decomposed = 5 mol
Solution:
Chemical equation:
2HgO → 2Hg + O₂
now we will compare the moles of HgO and O₂.
HgO : O₂
2 : 1
5 : 1/2×5 = 2.5
Thus, from 5 moles of HgO 2.5 moles of oxygen are produced.
A treatment plant uses a CMFR as the reactor for the removal of manganese via an oxidation reaction by the addition of potassium permanganate. If the influent manganese concentration is 0.86 mg/L, the plant has a treatment capacity of 3,800 m3/d, the reactor has a volume of 45 m3, and manganese reacts with potassium permanganate in a first order reaction with a reaction rate constant of 0.0125 s-1, what is the effluent concentration
Answer:
the effluent concentration is 0.06236 mg/L
Explanation:
Given that;
treatment capacity [tex]V_{0}[/tex] = 3,800 m³/d = ( 3,800 × 86.4) = 43.98 L/sec
reactor's volume V = 45 m³ = (45 × 1000) = 45,000 L
reaction rate constant K = 0.0125 s⁻¹
influent manganese concentration [tex]CA_{0}[/tex] = 0.86 mg/L
-[tex]r_{A}[/tex] = [tex]KC_{A}[/tex]
Now, performance equation for CSTR is expressed as follows;
[tex]\frac{V}{V_{0} }[/tex] = [tex]\frac{CA_{0} -CA _{} }{-r_{A} }[/tex]
[tex]\frac{V}{V_{0} }[/tex] = [tex]\frac{CA_{0} -CA _{} }{KC_{A} }[/tex]
So we substitute
45000L / 43.98 L/sec = ( 0.86 mg/L - CA) / 0.0125 CA
we cross multiply
562.5CA = 37.8228 - 43.98CA
562.5CA + 43.98CA = 37.8228
606.48CA = 37.8228
CA = 37.8228 / 606.48
CA = 0.06236 mg/L
Therefore, the effluent concentration is 0.06236 mg/L
A rock's mass is a:
A. all of the above
B. chemical property
C. physical property
D. constant property
Answer:
all of the above
Explanation:
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To solve the ultraviolet catastrophe, Planck applied quantization to: Select the correct answer below:
A. vibrational energies of atoms
B. orbital energies of electrons
C. kinetic energies of photons
D. temperature of the system
Answer:
Vibrational energies of atoms
Explanation:
Planck applied quantization to Vibrational energies of atoms because in Black body spectrum prediction a blackbody at equilibrium is expected to radiate energies at various Frequencies ( i.e. increase in radiated energy ∝ increase in frequency ) but towards the ultraviolet region of the spectrum the energy radiated begins to drop as frequency increases. The phenomenon of drop in energy with increase in frequency is termed Ultraviolet catastrophe. hence to solve this phenomenon Planck applied quantization to Vibrational energies of atoms
After a big game, you put your water bottle inside the refrigerator. The next
day you see that your water bottle has become dented. Which statement
best describes what happened?
A.
Heat molecules left the water bottle.
B.
Some air molecules were broken down.
C.
The air particles slowed down and got closer together.
D.
Some of the air molecules escaped the water bottle.
Mostly and for what I would say is A
The gases can undergo compression when subjected to lower temperatures and pressure. The water bottle becomes dented as the collision slowed down and got closer to each other. Thus, option C is correct.
What is freezing?Freezing has been the physical process that is involved in changing the states of matter from liquid to solids. This results in a decrease in the entropy of the water which decreases the heat and randomness of the particles.
As the temperature decreases the collision and the kinetic energy of the particles decreases. This results in the loss of entropy and makes the molecules or the particles show a higher force of attraction leading to close packing. The space becomes dense and tightly packed.
As the particle becomes closely packed it dents the water bottle at low temperature as now it has its own shape (solids) unlike the liquids. The lower temperature converts the liquids into solids.
Therefore, as the water freezes the bottle experiences a dent as ice is formed from liquids by freezing.
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Question 4 of 10
What form of the ideal gas law would you use to calculate the temperature of
a gas?
O A. Ta
B. Y =
C. P = nRT
D. n =
RT
Answer:
C. P = nRT
Explanation:
PV = nRT, where n is a number of moles and R is the universal gas constant, R = 8.31 J/mol ⋅ K.
Hope this helps :)
Answer:T =PV/nR
Explanation:
Rank the following elements by electron affinity, from most positive to most negative EA value.
Rank from most positive to most negative. To rank items as equivalent, overlap them.
bromine
sodium
tellurium
helium
phosphorus
Answer:
Explanation:
Bromine >Tellurium > Phosphorus > Helium > Sodium
Electron affinity of Bromine , Tellurium , Phosphorus are positive , of helium is zero and of sodium is negative .
how is the name of the second element in a covalent molecule changed
Answer:
See explanation
Explanation:
Here we are trying to see how a binary covalent compound is named. A binary covalent compound comprises of only two elements held together by covalent bonds.
The first element retains its normal name whereas the second element has the suffix -ide added to it.
For instance, CO2 is named as carbon dioxide, HBr is named as hydrogen bromide etc.
Answer: it's ide
Explanation:
Got it right in the quiz
Plz help guys help me
Answer:
Six Steps to Control Workplace Hazards
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Step 2: Substitute the hazard with something safer. ...
Step 3: Isolate the hazard from people. ...
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Step 6: Use Personal Protective Equipment (PPE)
Explanation:
i it true?
How can the IR spectrum be used to show that there is not starting material left and the products are alcohols
Answer:
hello your question is incomplete attached below is the complete question
answer :
Absence of c = c = C-H of the peak and the presence of -O-H and C-O peak shows that there is presence of Alcohols as products and it also shows that there is no starting material left
Explanation:
To provide that there is no starting material left and products are alcohols using the IR spectrum we will apply hydroboration oxidation
Absence of c = c = C-H of the peak and the presence of -O-H and C-O peak shows that there is presence of Alcohols as products and it also shows that there is no starting material left
attached below is the detailed solution
Give the structure that corresponds to the following molecular formula and H1 NMR spectrum: The proton N M R shows a triplet at 0.9 p p m integrating to 11238 and a quartet at 1.4 integrating to 7473. THere is a singlet at 1.35 p p m integrating to 1275 that disappears after a D 2 O shake. The unknown compound has a molecular formula of C 7 H 16 O. The magenta numbers in the spectrum are the relative integrals in arbitrary units. Draw the structure.
Answer:
Kindly check the attached picture for the diagram of the chemical compound.
Explanation:
So, the following parameters were given from the question above;
=> A triplet at 0.9 ppm and a quartet at 1.4 ppm, a singlet at 1.35 ppm. Now, the unknown compound has a molecular formula of C7H16O.
For a triplet at 0.9ppm, there are nine (9) atoms of hydrogen, for the quartet at 1.4ppm there are six(6) atoms of hydrogen and for the singlet at 1.35 ppm, the number of hydrogen atoms is one(1). Hence, the total number of hydrogen atoms = 16.
Therefore, number of bondings = [(2 × number of carbon atoms) + 2 - number of hydrogen atoms present on the compound)/2 .
Thus number of bonds =[( 2× 7) + 2 - 16] ÷ 2 = 0.
Hence, there is no double bond or ring in the compound.
Will liquid with higher density be more or less buoyant?
Answer:
Explanation:
if it has a lower density than the liquid it's in will float
Helium on the Moon was found to be 0.420% 2He, 2.75% 3He, and 96.83% 4He. What is the average atomic mass of helium on the Moon?
Answer:
Average atomic mass = 3.9 amu
Explanation:
Given data:
Percent abundance of He-2 = 0.420%
Percent abundance of He-3 = 2.75%
Percent abundance of He-4 = 96.83%
Average atomic mass = ?
Solution:
Average atomic mass = (abundance of 1st isotope × its atomic mass) +(abundance of 2nd isotope × its atomic mass) + (abundance of 3rd isotope × its atomic mass) / 100
Average atomic mass = (0.420×2)+(2.75×3) +(96.83×4)/100
Average atomic mass = 0.84 + 8.25 +387.32 / 100
Average atomic mass = 396.41 / 100
Average atomic mass = 3.9 amu.
A catalyst decreases the activation energy of a particular exothermic reaction by 56 kJ/mol, to 35 kJ/mol. Assuming that the mechanism has only one step, and that the products are 78 kJ lower in energy than the reactants, sketch approximate energy-level diagrams for the catalyzed and uncatalyzed reactions. What is the activation energy for the uncatalyzed reverse reaction
Answer:
Activation energy for the uncatalyzed reverse reaction = 103 kJ/mol
Explanation:
Activation energy decreases from = 56 kj/mol to 35 kj/mol
products = 78 KJ lower in energy than reactants
Activation energy for the uncatalyzed reverse reaction = 103 kJ/mol
attached below are the sketches of approximate energy-level for both catalyzed and uncatalyzed reactions
Joseph Priestly is frequently credited with the discovery of oxygen, and was reported to have produced molecular oxygen from the decomposition reaction of mercury(II) oxide, which is the reverse of the synthesis of HgO depicted in the following equation. 4 Hg(l) + 2 O2(g) LaTeX: \rightarrow → 4 HgO(s) Determine the value of LaTeX: \Delta ΔH°rxn for the synthesis, given that
Joseph Priestly is frequently credited with the discovery of oxygen, and was reported to have produced molecular oxygen from the decomposition reaction of mercury(II) oxide, which is the reverse of the synthesis of HgO depicted in the following equation. [tex]4Hg(l)+2O_2(g)\rightarrow 4 HgO(s) [/tex]Determine the value of [tex]\Delta ΔH°rxn[/tex] for the synthesis, given that [tex]\Delta H_f^0[/tex] for HgO is -90.7 kJ/mol.
Answer: The enthalpy change for this reaction is, -362.8 kJ
Explanation:
The balanced chemical reaction is,
[tex]4Hg(l)+2O_2(g)\rightarrow 4HgO(s)[/tex]
The expression for enthalpy change is,
[tex]\Delta H=\sum [n\times \Delta H_f(product)]-\sum [n\times \Delta H_f(reactant)][/tex]
[tex]\Delta H=[(n_{HgO}\times \Delta H_{HgO})]-[(n_{O_2}\times \Delta H_{O_2})+(n_{Hg}\times \Delta H_{Hg})][/tex]
where,
n = number of moles
[tex]\Delta H_{O_2}=0[/tex] (as heat of formation of substances in their standard state is zero
[tex]\Delta H_{Hg}=0[/tex] (as heat of formation of substances in their standard state is zero
Now put all the given values in this expression, we get
[tex]\Delta H=[(4\times -90.7)]-[(2\times 0)+(4\times 0)][/tex]
[tex]\Delta H=-362.8kJ[/tex]
Therefore, the enthalpy change for this reaction is, -362.8 kJ
Based on the following chemical equation how many molecules of Hydrogen (H) are present in the reactants side?
2H2 + O2 ----> 2H2O
Question 1 options:
1
2
3
4
Answer:
2
Explanation:
Based on the chemical equation, the number of molecules of hydrogen gas in the reactant side is 2.
This is indicated by the coefficient before reactant.
A molecule is a covalent compound that has discrete or separate units.
So H₂ is made up of two atoms of hydrogen that has been covalently bonded together by sharing their valence electrons.
From the reaction expression:
2 molecules of hydrogen gas combines with 1 molecule of oxygen gas to produce 2 molecules of water.