Answer:
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A 46.6-mgmg sample of boron reacts with oxygen to form 150 mgmg of the compound boron oxide. Part A What is the empirical formula of boron oxide
Answer:
B₂O₃
Explanation:
Step 1: Calculate the mass of oxygen in 150 mg of boron oxide
Of 150 mg of boron oxide, 46.6 mg belong to boron. The mass of oxygen is:
150 mg - 46.6 mg = 103.4 mg
Step 2: Calculate the percent by mass of each element
We will use the following expression.
%Element = mElement/mCompound × 100%
%B = 46.6 mg/150 mg × 100% = 31.1%
%O = 103.4 mg/150 mg × 100% = 68.9%
Step 3: Divide each percentage by the atomic mass of the element
B: 31.1/10.81 = 2.88
O: 68.9/16.00 = 4.31
Step 4: Divide both numbers by the smallest one (2.88)
B: 2.88/2.88 = 1
O: 4.31/2.88 ≈ 1.5
Step 5: Multiply both numbers by 2 so that they are integers
B: 1 × 2 = 2
O: 1.5 × 2 = 3
The empirical formula is B₂O₃.
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Write the symbol for every chemical element that has atomic number less than 14 and atomic mass greater than 23.2 u.
Answer:
8 oxygen. 9 flourine. 10. Neon. 5 Boron
g n the following three compounds(1,2,3) arrange their relative reactivity towards the reagent CH3Cl / AlCl3. Justify your order
Answer:
3 > 2> 1
Explanation:
Aromatic compounds undergo electrophilic substitution reaction which passes through a positively charged intermediate to yield the product.
Substituted benzenes may be more or less reactive towards electrophilic aromatic substitution than benzene molecule depending on the nature of the substituent.
Certain substituents increase the ease of reaction of benzene towards aromatic substitution.
If we look at the compounds closely, we will notice that toluene reacts readily with CH3Cl / AlCl3. This is because, the methyl group is electron donating hence it stabilizes the positively charged intermediate produced in the reaction.
Carbonyl compounds are electron withdrawing substituents hence they decrease the magnitude of the positive charge and hence decrease the rate of electrophilic aromatic substitution.
The boiling point of a liquid is 50°C. What is this temperature on the Kelvin scale?
Answer:
323.15 or just 323 depending on the teacher
Which of the following statements correctly explains why bromination reactions are more selective than chlorination reactions.
a. bromine radical is less stable than chlorine radical, so it is more reactive and less choosy
b. bromine radical is more stable than chlorine radical, so it is more reactive and less choosy
c. bromine radical is more stable than chlorine radical, so it is less reactive and more choosy
d. bromine radical is less stable than chlorine radical, so it is less reactive and more choosy
e. relative radical stability is 3' radicals > 2" radicals> 1 radicals when bromine radicals snatch hydrogens from alkanes, but when chlorine radicals snatch hydrogens the resulting alkyl radical stability is 3 radicals < 2 radicals< 1' radicals
Answer: A bromine radical is more stable than chlorine radical, so it is less reactive and more choosy.
Explanation:
A chlorine atom being more electronegative in nature is able to attract a hydrogen atom more readily towards itself as compared to a bromine atom.
Since bromine is less electronegative in nature so bromine will be more selective as a hydrogen abstracting agent. As a result, bromine radical is more stable in nature than chlorine radical.
Thus, we can conclude that bromine radical is more stable than chlorine radical, so it is less reactive and more choosy.
There are four containers: a 100-mL beaker, 250-mL Erlenmeyer flask, a 500-mL beaker, and a 1-L Florence flask. They contain coffee, tea, water, and milk, although not in that order. Use the following facts to identify the beverage in each container.
a. the 500-mL container has a beverage commonly associated with breakfast.
b. the largest container has a colorless liquid (i.e. neither yellow nor orange).
c. the beverage in the smallest container is opaque. (you cannot see through it).
d. One clear liquid is in a container half the volume of a colored liquid.
e. The only combustible liquid has exactly twice the volume of an opaque liquid.
Answer:
There are four containers: a 100-mL beaker, 250-mL Erlenmeyer flask, a 500-mL beaker, and a 1-L Florence flask. They contain coffee, tea, water, and milk, although not in that order. Use the following facts to identify the beverage in each container.
a. the 500-mL container has a beverage commonly associated with breakfast.
b. the largest container has a colorless liquid (i.e. neither yellow nor orange).
c. the beverage in the smallest container is opaque. (you cannot see through it).
d. One clear liquid is in a container half the volume of a colored liquid.
e. The only combustible liquid has exactly twice the volume of an opaque liquid.
Explanation:
a. The 500-mL container has a beverage commonly associated with breakfast is coffee.
b. The largest container has a colorless liquid (i.e. neither yellow nor orange) water.
c. The beverage in the smallest container is opaque. (you cannot see through it) milk.
d. One clear liquid is in a container half the volume of a colored liquid tea.
The 500-mL container has a beverage commonly associated with breakfast is coffee. (rest answers are as follows)
How to indentify beverages ?The Indentification of the beverages can be done by knowing the content and optical activity that uniquely identify the container.
The 500-mL container has a beverage commonly associated with breakfast is coffee.The largest container has a colorless liquid (i.e. neither yellow nor orange) water.The beverage in the smallest container is opaque. (you cannot see through it) milk.One clear liquid is in a container half the volume of a colored liquid tea.Learn more about optical activity here ;
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What were the advantages for Mendel in using pea plants for his breeding experiments?
Answer:
He chose pea plants because they were easy to grow, could be bred rapidly, and had several observable characteristics, like petal color and pea color.
Explanation:
formula of
Al³⁺ and SO₄²⁻
Answer:
The formula of Al³⁺ and SO₄²⁻ is aluminum sulfate.
Explanation:
The formula for aluminum sulfate is Al₂(SO₄)₃. If we say in terms of ions. The ions are Al³⁺. It is a positive ion or the cation. Other ion is SO₄²⁻. It is sulfate ion. It is anion.
Aluminum sulphate is used in water purification and as a mordant in dyeing and printing textiles.
Hence, the formula of Al³⁺ and SO₄²⁻ is aluminum sulfate.
What volume (mL) of the sweetened tea described in Example 1 contains the same amount of sugar (mol) as 10 mL of the soft drink in this example
The question is incomplete, the complete question is:
What volume (mL) of the sweetened tea described in Example 3.14 contains the same amount of sugar (mol) as 10 mL of the soft drink in this example. The example is attached below.
Answer: 75 mL of sweetened tea will contain the same amount of sugar as in 10 mL of soft drink
Explanation:
We first calculate the number of moles of soft drink in a volume of 10 mL
The formula used to calculate molarity:
[tex]\text{Molarity of solution}=\frac{\text{Moles of solute}\times 1000}{\text{Volume of solution (mL)}}[/tex] .....(1)
Taking the concentration of soft drink from the example be = 0.375 M
Volume of solution = 10 mL
Putting values in equation 1, we get:
[tex]0.375=\frac{\text{Moles of sugar in soft drink}\times 1000}{10}\\\\\text{Moles of sugar in soft drink}=\frac{0.375\times 10}{1000}=0.00375mol[/tex]
Calculating volume of sweetened tea:
Moles of sugar = 0.00375 mol
Molarity of sweetened tea = 0.05 M
Putting values in equation 1, we get:
[tex]0.05=\frac{0.00375\times 1000}{\text{Volume of sweetened tea}}\\\\\text{Volume of sweetened tea}=\frac{0.00375\times 1000}{0.05}=75mL[/tex]
Hence, 75 mL of sweetened tea will contain the same amount of sugar as in 10 mL of soft drink
The rate law for the following reaction: H2SiF6(aq)+2NaF(aq)+3H2O(aq)⟶Na2SiO3(s)+8HF(aq) is second order in H2SiF6, zero order in NaF and first order in H2O. By what factor will the reaction rate change if the concentrations of all reactants are tripled?
Answer:
The rate law for the following reaction:
H2SiF6(aq)+2NaF(aq)+3H2O(aq)⟶Na2SiO3(s)+8HF(aq)
is second order in H2SiF6, zero order in NaF and first order in H2O.
Methanol has the formula CH3OH. What is the predominant intermolecular force between methanol molecules?
ANSWER:
dispersion forces
dipole forces
ionic bonds
hydrogen bonds
Answer:
hydrogen bonds
Explanation:
similarly CH3OH also has a OH group and H hydrogen thus it will also form h-bonding.
The speed of sound depends on the __?_____ and ____?____ of the medium through which it travels
Answer:
Density and rigidity
Which of the following molecules can be used in catabolic reactions to generate the carbon backbones required for gluconeogenesis?
a. glutathione, a short peptide containing glutamate, serine and histidine
b. butyrate, a short chain fatty acid
c. fructose, a monosaccharide
d. starch, a polysaccharide
Answer:
The correct option is A
Explanation:
Some amino acids, called glucogenic amino acids, when catabolized convert there carbon backbones to tricarboxylic acid (TCA) cycle intermediates. These intermediates can be subsequently metabolized into carbon dioxide and water with the release of ATP or the formation of glucose (known as gluconeogenesis.
All amino acids (with the exception of leucine and lysine) are glucogenic and can thus generate the carbon backbones required for gluconeogenesis. Thus, the correct option is a.
What does the term spontaneous mean in chemical reactions?
A. Producing heat as a product
B. Occurring without added energy
C. Occurring only at high temperatures
D. Occurring in an aqueous solution
Answer:
B
Explanation:
Spontaneous in chemical reactions means without any external input.
Occurring without added energy. Hence, option B is correct.
What is a spontaneous reaction?A spontaneous reaction is a reaction that supports the formation of products under the conditions under which the reaction is happening.
Spontaneous Reaction- a reaction that favours the formation of products at the conditions under which the reaction is occurring.
A non-spontaneous reaction can be made spontaneous if it is inside a controlled environment, this is what happens in nuclear power plants that create atomic fusion and fission in chambers that are controlled to control different particles to create nuclear active rays.
Hence, option B is correct.
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A chemistry grad student measures the performance of the new pump in his lab. The result is:Convert to
Answer:
The correct answer is - 0.0188 mJ*s^-1.
Explanation:
In order to convert the kPA value to PA value--
and then convert PA unit to 1 kgm^-1s^-2
And in finally convert mm to m
The value that come should be convert from kgm^2s^-2 to and then convert J to mJ or kJ by dividing 100 or 100 subsequently.
As no question given this method can be followed for the answer.
Determine whether each of the properties described applies to volumetric or graduated glassware. 1. Used for applications in which great accuracy is needed_____.a. volumetricb. graduated 2. Capable of measuring a range of volumes of liquid_____.a. volumetric
b. graduated 3. Designed to measure one specific volume of liquid_____.a. volumetric
b. graduated
Answer:
1) volumetric
2) graduated
3) volumetric
Explanation:
A volumetric glassware is a glassware that is marked at a particular point. A typical example of a volumetric glassware is the volumetric flask. A volumetric glassware is capable of measuring only a specific volume of a liquid.
On the other hand, graduated glassware can measure a range of volumes of liquid. However, a volumetric glassware is still required where a high degree of accuracy is important.
I need help solving this!
For the reaction C + 2H2 → CH4, how many moles of hydrogen are needed to make 146.6 grams of methane, CH4 ?
Round your answer to the nearest tenth. If you answer is a whole number like 4, report the answer as 4.0
Use the following molar masses. If you do not use these masses, the computer will mark your answer incorrect.:
Element
Molar Mass
Hydrogen
1
Carbon
12
Answer: Moles of hydrogen required are 4.57 moles to make 146.6 grams of methane, [tex]CH_{4}[/tex].
Explanation:
Given: Mass of methane = 146.6 g
As moles is the mass of a substance divided by its molar mass. So, moles of methane (molar mass = 16.04 g/mol) are calculated as follows.
[tex]Moles = \frac{mass}{molar mass}\\= \frac{146.6 g}{16.04 g/mol}\\= 9.14 mol[/tex]
The given reaction equation is as follows.
[tex]C + 2H_{2} \rightarrow CH_{4}[/tex]
This shows that 2 moles of hydrogen gives 1 mole of methane. Hence, moles of hydrogen required to form 9.14 moles of methane is as follows.
[tex]Moles of H_{2} = \frac{9.14}{2}\\= 4.57 mol[/tex]
Thus, we can conclude that moles of hydrogen required are 4.57 moles to make 146.6 grams of methane, [tex]CH_{4}[/tex].
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Answer:
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True or false: Boron contains 2s22p1 valence electrons, so only one p orbital is needed to form molecular orbitals.
Answer:
True
Explanation:
The valence orbitals of boron are 2s2 2p1. We have to recall that all the valence orbitals whether full or empty are involved in the formation of molecular orbitals.
The number of molecular orbitals formed is equal to the number of atomic orbitals that are combined.
Since there are two valence orbitals and there is only one p orbital among the valence orbitals, it is true that only one p orbital is needed to form molecular orbitals in boron.
g Calculate the number of grams of aluminum that is produced in 1.00 h by the electrolysis of molten AlCl3 if the electrical current is 10.0A.
Answer:
3.36 grams Al°(s)
Explanation:
Given AlCl₃(s), determine the mass (grams) of Al°(s) produced from electrolysis of Aluminum Chloride at 10.0 amps for 1.00 hour.
AlCl₃(s) + 378.3°F (=192.4°C) => Al⁺³(l) + 3Cl⁻(l)
formula wt. Al° = 27g/mol
Faraday Constant (F°) = 96,500 amp·sec
? grams Al°(s) = 10.0amps x (1 mole e⁻/96,500amp-sec) x (1 mole Al°(s)/3 mole e⁻) x (27g Al°(s)/1 mole Al°(s)) x 3,600 sec = 3.36 grams Al°(s)
The 3.36 grams of aluminum are produced in 1 hour by the electrolysis of molten AlCl₃ when 10A current is passed.
What is electrolysis?Electrolysis is a process that uses an electrical current to break chemical compounds. The electric current is passed through the substance to bring the chemical change by gain or loss of electrons.
The electrolysis of the aluminum chloride in the molten state is represented as:
AlCl₃ → Al³⁺ + 3Cl⁻
At cathode: Al³⁺ + 3e⁻ → Al (s)
Given, the current. I = 10 A and t = 1 hr = 3600 s
We know that the current is calculated from the equation: I = q/t
q = I× t
q = (10A) × (3600s)
q = 36 × 10³ C
We know, 96500 C of the charge has electrons = 1 mol
36 × 10³ C of the charge has electrons = 0.373 mol
3 moles of electrons required to produce aluminum = 1 mol
0.373 mol of electrons will produce aluminum = 0.373/3 = 0.124 mol
We know that, the mass of one mole of Al = 27g
The mass of 0.124 mol of Al = 27 × 0.124 = 3.36 g
Therefore, the aluminum produced in 1 hour by the electrolysis of molten AlCl₃ is equal to 3.36 grams.
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Rank the following chemical species from lowest absolute entropy (So) (1) to highest absolute entropy (5) at 298 K?
a. Al (s)
b. H2O (l)
c. HCN (g)
d. CH3COOH (l)
e. C2H6 (g)
Answer:
Rank the following chemical species from lowest absolute entropy (So) (1) to highest absolute entropy (5) at 298 K?
a. Al (s)
b. H2O (l)
c. HCN (g)
d. CH3COOH (l)
e. C2H6 (g)
Explanation:
Entropy is the measure of the degree of disorderness.
In solids, the entropy is very less compared to liquids and gases.
The entropy order is:
solids<liquids<gases
Among the given substances, water in liquid form has a strong intermolecular H-bond.
So, it has also less entropy.
Next acetic acid.
Between the gases, HCN, and ethane, ethane has more entropy due to very weak intermolecular interactions.
HCN has slight H-bonding in IT.
Hence, the entropy order is:
Al(s) < CH3COOH (l) <H2O(l) < HCN(g) < C2H6(g)
A student dropped a pea size amount of K2CO3 into a solution of HCl(aq). He observed the formation of gas bubbles and collected the gas into another test tube. The student performed a splint test and observed that the splint was extingished when he placed the splint into the test tube of the gas. What can be said about the results of this students experiment?
a. The student completed the experiment correctly and there were no errors in the experiment.
b. The experiment was performed incorrectly. K2CO3 doesn't react with HCl. Therefore, the student picked up the wrong compound when conducting the experiment.
c. The student performed the splint test incorrectly. He should of observed the splint flare up when the splint was placed in the test tube.
d. The student performed the splint test incorrectly. He should of observed a popping sound when the splint was placed in the test tube.
Answer:
The student completed the experiment correctly and there were no errors in the experiment.
Explanation:
When a pea size amount of K2CO3 is dropped into a solution of HCl, the following reaction occurs;
K2CO3(s) + 2HCl(aq) ----> 2KCl(aq) + CO2(g) + H2O(l)
The gas CO2 does not support burning hence, when the student performed a splint test and observed that the splint was extinguished when he placed the splint into the test tube of the gas.
Hence, the experiment was properly conducted and the student completed the experiment correctly and there were no errors in the experiment.
The addition of chromic acid or chromate is a qualitative test for alcohols as the reaction causes a color change. However, not all alcohols react with chromic acid or chromate. Determine whether the named alcohol will react with chromic acid or chromate to cause a color change.
a. 3-hexanol
b. 1 -butanol
c. 2-pentanol
d. 3-ethyl-3-pentanol
Answer:
3-hexanol
1 -butanol
2-pentanol
Explanation:
Let us recall that chromic acid or chromate are strong oxidizing agents. When they are oxidized, their colour changes from orange to green.
This shows a reduction in chromic acid or chromate. The reaction of chromic acid or chromate with a primary alcohol yields a carboxylic acid while reaction with a secondary substrate yields an alkanal.
Note that Tertiary alkyl halides are not be oxidized hence reactions involving a point where invitation carried along occur.
3-ethyl-3-pentanol is a tertiary alkyl halide hence it can not be oxidized.
a sample of salt has 1.74 moles of sodium chloride. how many formula units of the ionic compound are in the sample?
Answer:
A sample of salt has 1.74 moles of sodium chloride. how many formula units of the ionic compound are in the sample?
Explanation:
Given, 1.74 moles of NaCl.
Since one mole of NaCl consists of --- [tex]6.023 * 10^2^3[/tex] formula units.
Then, 1.74mol of NaCl contains how many formula units of NaCl?
[tex]1.74 mol x \frac{6.023x10^2^3}{1 mol} \\=10.5x10^2^3[/tex]formula units.
Hence, the given sample has 10.5x10^23 formula units.
Explain why the balls representing fluorine (teal) and hydrogen (white) have only one peg, while carbon (black) has four.
Answer:
Hydrogen and fluorine form only one bond while carbon forms four bonds to other atoms.
Explanation:
This question brings us to the idea of valency. Fluorine is univalent while carbon is tetravalent.
Univalent means that fluorine can only form one bond to hydrogen while carbon forms as much as four bonds because it is tetravalent.
Hence fluorine and hydrogen have only one peg while carbon has four.
Which one of the following reactions is NOT balanced?
2 CO + O2 + 2 CO2
2 SO2 + O2 +2 SO3
2 KNO3 + 10 K 5 K20 + N2
SF4 + 3 H2O → H2SO3 + 4HF
Answer:
co+ o2+ 2co2 is not balanced reaction
Observe as equações e de acordo com Brönsted-Lowry, os compostos destacados são, respectivamente
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EXTRACTION OF CAFFEINE 1.Explain the reason each step of the separation is performed with three portions of the solvent rather than with a single portion of solvent. (e.g. Done in triplicate.) (0.5 pt) 2.Why should a separatory funnel not be vigorously shaken
Answer:
Throughout the explanations section below you will find a description of the question.
Explanation:
(1)
Whether a solution would be positioned inside a separative funnel, combined water, as well as solvent, disintegrate particulate caffeine. In every stage, the caffeine content incorporated relies upon the coefficient of caffeine partitioning throughout the combination of water as well as fluid.Thus, increasingly caffeine is taken from the solvent whenever the moment you bring additional solvent. Consequently, we separate the solvent from the single component.(2)
For compounds to be mixed thoroughly and separated into different layers, a shuddering mixture within the dividing funnel would be essential.However, it vibrates the separation funnel forcefully, restricts airflow within the funnel, which can also induce the fluid under it to burst or causing fluid to fire.For each of the following changes at equilibrium, indicate whether the equilibrium shifts in the direction of products, reactants, or does not change: CaCO3(s)+heat⇌CaO(s)+CO2(g)
1) increasing the temperature
shifts equilibrium in the direction of the reactants
does not change
shifts equilibrium in the direction of the products
2) decreasing the volume of the container
shifts equilibrium in the direction of the reactants
shifts equilibrium in the direction of the products
does not change
3) adding a catalyst
shifts equilibrium in the direction of the reactants
shifts equilibrium in the direction of the products
does not change
4) adding more CaO(s)
does not change
shifts equilibrium in the direction of the reactants
shifts equilibrium in the direction of the products
Answer:
shifts equilibrium in the direction of the products
shifts equilibrium in the direction of the reactants
does not change
shifts equilibrium in the direction of the reactants
Explanation:
When a constraint such as a change in pressure, concentration or temperature is imposed on a reaction system in equilibrium, the equilibrium position will shift in such a way as to annul the constraint.
The reaction is endothermic as written. Hence, increase in temperature increases the rate of forward reaction thereby shifting the equilibrium position towards the products.
When the volume of a reaction is decreased, the equilibrium position shifts in the direction which produces the least total volume. In this case, decrease in volume shifts the equilibrium position towards the reactants.
A catalyst has no effect on the equilibrium position. However, a catalyst may cause equilibrium to be achieved faster or at a lower temperature.
When more CaO is added, the equilibrium position shifts towards the reactants side and more CaCO3 is produced.