Answer:
So first thing to do in these types of problems is write out your chemical reaction and balance it:
Mg + O2 --> MgO
Then you need to start thinking about moles of Magnesium for moles of Magnesium Oxide. Based on the above equation 1 mole of Magnesium is needed to make one mole of Magnesium Oxide.
To get moles of magnesium you need to take the grams you started with (.418) and convert to moles by dividing by molecular weight of Mg (24.305), this gives you .0172 moles of Mg.
The theoretical yield would be the assumption that 100% of the magnesium will be converted into Magnesium Oxide, so you would get, based on the first equation, .0172 mol of MgO. Multiplying this by the molecular weight of MgO (24.305+16) gives us .693 g of MgO.
The percent yield is what you actually got in the experiment, and for this you subtract off the total mass from the crucible mass, or 27.374 - 26.687, which gives .66 g of MgO obtained.
Percent yield is acutal/theoretical, .66/.693, or 95.24%.
I'll let you do the same for the second trial, and average percent yield is just an average of the two trials percent yield.
Hope this helps.
Wat are representative elements
Answer:
the representative elements are elements where the the s and p orbitals are filling. The transition elements are elements where the d orbitals (groups 3-11 on the periodic table) are filling, and the inner transition metals are the elements where the f orbitals are filling.
Explanation:
=)
Write the structural formula for a primary, a secondary, and a tertiary constitutionally isomeric alcohol of the molecular formula C5H12O.
Answer:
The structures of all isomeric alcohols of molecular formula C5H12O along with their IUPAC names are as shown.
Their classification of primary, secondary, and tertiary alcohols are -
1-pentanol -
2-pentanol -
3-pentanol
2-methylbutan-1-ol
2-methylbutan-2-ol
3-methylbutan-2-ol
3-methylbutan-1-ol
2,2-dimethylpropanol
an object is in set in ___ by using ___ to enact ___ upon the object.
A. motion,force,energy
B. energy,force,motion
C. Force,motion,energy
D. motion,energy, force
Answer: B. energy, force, motion
An object is set in [tex]\sf\purple{motion}[/tex] by using [tex]\sf\pink{force}[/tex] to enact [tex]\sf\red{energy}[/tex] upon the object.
A. motion, force, energy ✅
[tex]\large\mathfrak{{\pmb{\underline{\orange{Mystique35 }}{\orange{♡}}}}}[/tex]
Given the equation:
H2O (l)
KNO3(s) ————> KNO3(aq)
As H20(l) is added to KNO3(s) to form KNO3(aq), the entropy of the system…
1. decreases
2. increases
3. remains the same
Answer:
2. increases
Explanation:
...............
Answer:
1
Explanation:
Entropy is decrease when product is formed . because of there is stability in the product side.
Emily spills concentrated sodium hydroxide solution on her lab bench. What she should do first?
Answer:
Explanation: hell noo
1. Determine the volume of SO2 (at STP) formed from the reaction of 96.7 mol FeS2 and 55.0 L of O2 at 358 K and 1.20 atm.
4 FeS2(s) + 11O2(g) 2Fe2O3(s) + 8SO2(g)
Answer:
40.0L of SO2 are produced
Explanation:
To solve this question we need to find the moles of O2 using PV = nRT in order to find the moles. Thus, we can find the limiting reactant and the moles (And volume) of SO2 produced as follows:
Moles O2:
n = PV/RT
n = 1.20atm*55.0L / 0.082atmL/molK*358K
n = 2.25 moles of O2.
Clearly, limiting reactant is O2.
The moles of SO2 produced are:
2.25 moles of O2 * (8mol SO2 / 11mol O2) = 1.6351 moles SO2
Volume SO2:
V = nRT/P
V = 1.6351 moles SO2*0.082atmL/molK*358K / 1.20atm
V = 40.0L of SO2 are produced
1a. A researcher accidentally spilled some sand into his beaker containing crystalline compound X. Knowing what he did about melting points, he was not worried about obtaining the melting point of compound X with a few grains of sand present. Why
Answer:
See explanation
Explanation:
Many organic compounds have low melting points. This is due to the fact that many of these compounds are non polar.
However, compound X is slightly polar but still has a melting point which is far less than that of sand composed of a high melting point inorganic material.
Since sand has a much higher melting point compared to compound X, the researcher need not be worried that sand was spilled into his beaker.
For each system listed in the first column of the table below, decide (if possible) whether the change described in the second column will increase in GPS of the system, decrease S, or leave S unchanged. If you don’t have enough information to decide, check the “not enough information“ button in the last column. Note for advanced students: you may assume ideal gas and ideal solution behavior.
Answer:
For each system listed in first column of the table below, decide (if possible) whether the change described in the second column will increase the entropy S of the system, decrease S , or leave S unchanged. If you don?t have enough information to decide, check the not enough information button in the last column
Question 6 of 10
What is the relationship between temperature and kinetic energy?
O A. When all molecular motion stops, the temperature stops changing.
OB. As molecules move more quickly, the temperature increases.
C. As molecules slow down, the temperature starts to increase.
D. When all molecular motion stops, the temperature starts to
decrease
A diver exhales a bubble with volume of 250 mL at pressure of 2.4 atm and temperature of 15 C. How many gas particulate in this bubble?
Answer:
1.5x10²² particulates
Explanation:
Assuming ideal behaviour, we can solve this problem by using the PV=nRT formula, where:
P = 2.4 atmV = 250 mL ⇒ 250 / 1000 = 0.250 Ln = ?R = 0.082 atm·L·mol⁻¹·K⁻¹T = 15 °C ⇒ 15 + 273 = 288 KWe input the given data:
2.4 atm * 0.250 L = n * 0.082 atm·L·mol⁻¹·K⁻¹ * 288 KAnd solve for n:
n = 0.025 molFinally we calculate how many particulates are there in 0.025 moles, using Avogadro's number:
0.025 mol * 6.023x10²³ particulates/mol = 1.5x10²² particulatesLook at this picture.
Which process in the water cycle is shown in the picture?
evaporation
transpiration
condensation
precipitation
Answer:
condensation
Explanation:
the water has condensed from the gaseous form into rain drops
Answer:
precipitation
Explanation:
You are an intermediate product of an industrial process which intends to separate iron from its ore. A well known iron ore is hematite. Which of these ores does not contain iron?
Goethite
Malachite
Siderite
Limonite
Answer:
Malachite
Explanation:
Malachite is a copper carbonate hydroxide mineral, with the equation Cu2CO3(OH)2. This dark, green-joined mineral solidifies in the monoclinic precious stone framework, and frequently shapes botryoidal, sinewy, or stalagmitic masses, in cracks and profound, underground spaces, where the water table and aqueous liquids give the way to synthetic precipitation. So, the answer is malachite. Best of Luck!
What is the role of a decomposer in a food chain?
A. to move food from producers to consumers
B. to move food from consumers to other consumers
C. to make food for the ecosystem
D. to return matter to the environment
Answer:D
Explanation:
Decomposers decompose food and return it to the environment through the soil
what is the pH value of water
Answer:
The pH of pure water (H20) is 7 at 25oC, but when exposed to the carbon dioxide in the atmosphere this equilibrium results in a pH of approximately 5.2. Because of the association of pH with atmospheric gasses and temperature, it is strongly recommended that the water be tested as soon as possible.
la. A man was traveling by sie is allowed a maximum of 20kg luggage. The man
weighing 3.5kg, 15kg.2kg and 15kg
Find the excess weight of his luggage.
Express the excess weight as a percentage of the maximum weight allowed
Answer: The excess weight of the luggage is 15.5 kg and its percentage is 77.5%
Explanation:
Given values:
Maximum amount of luggage allowed = 20 kg
Amount of luggage man is carrying = [3.5 + 15 + 2 + 15] kg = 35.5 kg
Excessive weight of the luggage carried = Amount of luggage carrying - Maximum amount of luggage allowed
Excessive weight of the luggage carried = [35.5 - 20] = 15.5 kg
To calculate the percentage of excess weight, we use the equation:
[tex]\% \text{excess weight}=\frac{\text{Excess weight carried}}{\text{Maximum allowed}}\times 100[/tex]
Putting values in above equation, we get:
[tex]\% \text{excess weight}=\frac{15.5kg}{20kg}\times 100\\\\\% \text{excess weight}=77.5%[/tex]
Hence, the excess weight of the luggage is 15.5 kg and its percentage is 77.5%
Explain how barometric pressure is measured.
Answer:
inches of mercury (inHg or “Hg) or millibars.
A buffer solution contains 0.368 M hydrocyanic acid and 0.360 M potassium cyanide . If 0.0513 moles of sodium hydroxide are added to 225 mL of this buffer, what is the pH of the resulting solution
Solution :
Millimoles of hydrocyanic acid = 225 x 0.368
= 82.8
Millimoles of potassium cyanide = 225 x 0.360
= 81
Millimoles of sodium hydroxide = 51.3
Therefore,
pOH = pKb + log [salt - C / bas + C]
= 4.74 + log[82.8 - 51.3 / 81 + 51.3]
= 4.102
Therefore, pH = 9.05
A 1 liter solution contains 0.402 M hypochlorous acid and 0.302 M potassium hypochlorite. Addition of 0.332 moles of hydrochloric acid will:
Answer:
Lower the pH by several units.
Exceed the buffer capacity.
Explanation:
The options are:
*Raise the pH slightly
*Lower the pH slightly
*Raise the pH by several units
*Lower the pH by several units
*Not change the pH
*Exceed the buffer capacity
The hydrochloric acid reacts with potassium hypochlorite to produce hypochlorous acid. The amount of HCl added is the HClO produced and the KClO consumed. As the moles of HCl > moles KClO, all the KClO is consumed exceeding the buffer capacity and lowering the pH by several units.
Calculate the molality of a 35.4 % (by mass) aqueous solution of phosphoric acid (H3PO4) (35.4 % means 35.4 g of H3PO4in 100 g of solution)
Answer:
3.6124 m/kg
Explanation:
Molality is calculated as moles of solute (mol) divided by kilogram of solvent (kg). Here, we can find these numbers by using the 35.4%, which gives us 35.4 g of H3PO4 and 100 g of solution to work with.
To go from grams to moles for the phosphoric acid, you need to find the molar mass of the compound or element and divide the grams of the compound or element by that molar mass.
Here, the molar mass for phosphoric acid is 97.9952 g/mol. The equation would look like this:
35.4 g x 1 mol / 97.9952 g = 0.3612422 mol
Next, the 100 g of solvent can easily be converted to 0.1 kg of solvent.
To find the molality, divide the moles of solute and kilograms of solution.
0.3612422 mol / 0.1 kg = 3.6124 m/kg
Kc is 1.67 x 10^20 at 25 °C for the formation of iron(III) oxalate complex ion:
Fe^3+ (aq) + 3C2O4^2- (aq) <--> [Fe(C204)3]^3- (aq)
Determine the number of moles of C2O4^2- used to react with 0.53 moles of Fe^3+.
Answer:
[tex]n_{C_2O_4^{2-}}=1.59mol C_2O_4^{2-}[/tex]
Explanation:
Hello there!
In this case, according to the given information and chemical equation, it turns out possible for us to calculate the moles of C2O4^2- by firstly setting up the equilibrium expression:
[tex]Kc=\frac{[[Fe(C_2O_4)_3]^{3-}]}{[Fe^{3+}][C_2O_4^{2-}]^3}[/tex]
However, according to the question, we just need to apply the given 1:3 mole ratio in the chemical reaction, of iron (III) ions to oxalate ions to obtain:
[tex]n_{C_2O_4^{2-}}=0.53molFe^{3+}*\frac{3molC_2O_4^{2-}}{1molFe^{3+}}=1.59mol C_2O_4^{2-}[/tex]
Regards!
Identify the alkene obtained on dehydration of each of the following alcohols:
a. 3-Ethyl-3-pentanol
b. 1-Propanol
c. 2-Propanol
d. 2,3,3-Trimethyl-2-butanol
Answer:
Explanation:
The information below explains how dehydration of alcohol occurs to produce alkene.
Under the influence of a catalyst, alcohol dehydrates to produce an alkene and water. To produce alkene and water, the reaction eliminates the OH group from alcohol containing the carbon atom and the hydrogen atom from a neighboring carbon atom via the same molecule.
The –OH group in alcohol contribute two(2) electrons to H+ out from the acid reagent, resulting in the formation of an alkyloxonium ion. This ion serves as an excellent leaving group, allowing a carbocation to form. The nucleophile which acts as the deprotonated acid subsequently attacks and creates a double bond with the hydrogen next to the carbocation.
Gaseous methane CH4 will react with gaseous oxygen O2 to produce gaseous carbon dioxide CO2 and gaseous water H2O. Suppose 0.963 g of methane is mixed with 1.2 g of oxygen. Calculate the maximum mass of water that could be produced by the chemical reaction. Round your answer to 2 significant digits.
Answer:
[tex]m_{H_2O}=0.676gH_2O[/tex]
Explanation:
Hello there!
In this case, according to the given information, it turns out possible for us to calculate the maximum mass of water by firstly setting up the undergoing chemical reaction as follows:
[tex]CH_4+2O_2\rightarrow CO_2+2H_2O[/tex]
Thus, we are able to firstly calculate the moles of water produced by both methane and oxygen in order to identify the limiting reactant, which is related to maximum of water:
[tex]0.963 gCH_4*\frac{1molCH_4}{16gCH_4}*\frac{2molH_2O}{1molCH_4} =0.120molH_2O\\\\1.2gO_2*\frac{1molO_2}{32gO_2}*\frac{2molH_2O}{2molO_2} =0.0375molH_2O[/tex]
Thus, we infer the limiting reactant is O2 and therefore we can obtain up to 0.0375 moles of water, which are related to the following mass:
[tex]m_{H_2O}=0.0375molH_2O\frac{18.02gH_2O}{1molH_2O}=0.676gH_2O[/tex]
Regards!
When optically active (R)-2-methylcyclohexanone is treated with either aqueous base or acid, racemization occurs. Explain.
Answer:
See explanation
Explanation:
Racemization is said to occur when a 1:1 ratio of (+) and (-) enantiomers of a compound are produced in a reaction.
The reaction of optically active (R)-2-methylcyclohexanone with either aqueous base or acid leads to the formation of a planar enol species for reaction with acid and a planar enolate species for reaction with base.
Both reactions involves the formation of achiral species which reverts back to the chiral product with equal chances of the formation of both enantiomers of the product during the process. This leads to racemization of the product in both cases.
Racemization of the optically active (R)-2-methylcyclohexanone results from the production and subsequent interconversion of intermediates during the reaction with an aqueous base or acid. This is due to the inversion of stereochemistry at the chiral centre.
Racemization can happen when an optically active molecule is exposed to an aqueous base or acid because the compound's enantiomers are interconverted. The carbon-carbon bond next to the carbonyl group in (R)-2-methylcyclohexanone breaks as a result of the chemical reaction with the aqueous base or acid. The creation of the negatively charged intermediate known as the enolate ion occurs when a base, such as hydroxide ions, is present and attacking the carbonyl carbon. The carbonyl group can then be reformated by this enolate ion after it has undergone a nucleophilic attack on a proton.
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A community has a nearby forest that has some insect-damaged trees that are dying. They decide to cut the dying trees and sell the wood for
firewood.
How does science knowledge support this solution?
A. Cutting down the trees allows more animals to live in the forest.
B. Using the trees for firewood eliminates pollution caused by heating homes.
C. Selling the diseased trees as firewood allows the community to make money.
D. Removing the diseased trees allows the remaining trees to get more water and sunlight.
Determine the number of moles of C in each sample
2.0 mol CH4, 0.175 mol C2H6,
4.21 mol C4H10, 24.5 mol C8 H18
Explanation:
In [tex]CH_4[/tex]:Given moles = 2.0 moles
1 mole of methane contains 1 mole of carbon and 4 moles of hydrogen
Moles of carbon in [tex]CH_4=(2.0\times 1)=2.0 moles[/tex]
In [tex]C_2H_6[/tex]:Given moles = 0.175 moles
1 mole of ethane contains 2 moles of carbon and 6 moles of hydrogen
Moles of carbon in [tex]C_2H_6=(0.175\times 2)=0.35 moles[/tex]
In [tex]C_4H_{10}[/tex]:Given moles = 4.21 moles
1 mole of butane contains 4 moles of carbon and 10 moles of hydrogen
Moles of carbon in [tex]C_4H_{10}=(4.21\times 4)=16.84 moles[/tex]
In [tex]C_8H_{18}[/tex]:Given moles = 24.5 moles
1 mole of octane contains 8 moles of carbon and 18 moles of hydrogen
Moles of carbon in [tex]C_8H_{18}=(24.5\times 8)=196 moles[/tex]
What is the price coke difference between a strong and weak acid?
Explanation:
Strong acids are those that are completely ionized in body fluids, and weak acids are those that are incompletely ionized in body fluids. Hydrochloric acid (HCl) is considered a strong acid because it is present only in a completely ionized form in the body, whereas carbonic acid (H2 CO3) is a weak acid because it is ionized incompletely, and, at equilibrium, all three reactants are present in body fluids. See the reactions below.
H2 CO3 (acid)↔H+ + HCO3- (base)
MAY IT HELPS U MATE ☃️☃️
Compounds containing chlorine have long been used to disinfect the water in swimming pools, but in recent years a compound of a less corrosive halogen has become a popular alternative disinfectant. What is the name of this fourth-row element
Explanation:
A period 4 element is one of the chemical elements in the fourth row (or period) of the periodic table of the elements.
...
Period 4 element.
Hydrogen Rubidium
Strontium
Yttrium
Zirconium
Niobium
To solve this we must be knowing each and every concept related to disinfectant. Therefore, chlorine dioxide is used as alternative disinfectant.
What is disinfectant?A disinfectant is indeed a chemical agent or compound that is used to kill or inactivate germs on inert surfaces. Disinfection may not always destroy all germs, particularly antibiotic resistant spores; it is more successful than sterilization, which involves a harsh physical or chemical procedure that kills all forms of life.
Compounds containing chlorine have long been used to disinfect the water in swimming pools, but in recent years a compound of a less corrosive halogen has become a popular alternative disinfectant. Chlorine dioxide is used as alternative disinfectant.
Therefore, chlorine dioxide is used as alternative disinfectant.
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Fill in the blank to complete the statement
Answer:
I dont get it what words are we using bc I see words on the side just it doesn't make any sense
An infant acetaminophen suspension contains 80 mg/0.80 mL suspension. The recommended dose is 15 mg/kg body weight.
How many milliliters of this suspension should be given to an infant weighing 13 lb.
Answer:
0.8853 mL
Explanation:
First we convert 13 lb to kg, keeping in mind that 1 lb = 0.454 kg:
13 lb * [tex]\frac{0.454kg}{1lb}[/tex] = 5.902 kgThen we calculate how many mg of acetaminophen should be given, using the recommended dose and infant mass:
15 mg/kg * 5.902 kg = 88.53 mgFinally we calculate the required mL of suspension, using its concentration:
88.53 mg ÷ (80 mg/0.80 mL) = 0.8853 mLThe molecule β-carotene has λ 450 nm, and ɛ = 15,000 m2 mol-1. Calculate the absorption (A) expected for a solution in which 0.1 mg has been dissolved in 10 ml of water (given: the molecular weight of β-carotene, C40H56, as 536) with a path length of 1 cm. Group of answer choices
Answer: The absorbance for a solution is 0.0028
Explanation:
To calculate the absorption of a solution, the equation by Beer-Lambert law is used:
[tex]A=\varepsilon \times b\times C[/tex]
OR
[tex]A=\varepsilon \times b\times \frac{\text{Given mass of solute}\times 1000}{\text{Molar mass of solute}\times \text{Volume of solution (mL)}}[/tex]
where,
A = absorbance = ?
[tex]\varepsilon[/tex] = molar absorptivity = [/tex]15000m^2mol^{-1}L[/tex]
b = path length = 1 cm = 0.01 m (Conversion factor: 1 m = 100 cm)
Given mass of [tex]\beta-[/tex] carotene = 0.1 mg = 0.0001 g (Conversion factor: 1 g = 1000 mg)
Molar mass of [tex]\beta-[/tex] carotene = 536 g/mol
Volume of solution = 10 mL
Putting values in equation 1:
[tex]A=15000\times 0.01\times \frac{0.0001\times 1000}{536\times 10}\\\\A=0.0028[/tex]
Hence, the absorbance for a solution is 0.0028
