Answer:
Explanation:
Chemical change
which of the following experiments raises ethical concerns
Answer:
Research that releases a poisonous gas into the air.
Explanation:
Since I don't know the options I will guess it is ^
The mass percent of element X
in X(NO3)2 is 52.55%.
Chemical analysis of a pure
sample of X(NO3)2 shows that
it contains 67.50 g of element
X. What is the total mass of
the pure sample?
Answer:
128.4 g
Explanation:
Step 1: Given data
Mass percent of element X in X(NO₃)₂: 52.55%Mass of the element X in the sample: 67.50 gStep 2: Determine the total mass of the sample
The mass percent of element X in X(NO₃)₂ is 52.55%, that is, there are 52.55 g of X every 100 g of X(NO₃)₂. Then, the mass of X(NO₃)₂ that contains 67.50 g of X is:
67.50 g X × 100 g X(NO₃)₂/52.55 g X = 128.4 g X(NO₃)₂
An eccentric chemistry professor (not mentioning any names) stops in every day and orders 200ml of Sumatran coffee at precisely 75.0°C. You then need to add enough milk at 5.00°C to drop the temperature of the coffee, initially at 95.0°C, to the ordered temperature.
Answer:
68.97g of milk must be added
Explanation:
To solve this problem we need to use the equation:
Q = C*m*ΔT -Coffee cup calorimeter equation-
This equation relates mass and change in temperature with heat of solution, Q.
The energy that decreases in the milk is the same that increases in the milk. That is:
Q(milk) = Q(tea)
Using the equation:
4.184J/molK* Mass milk * (65.0°C - 7.00°C) = 4.184J /molK * 200g (Tea) * (85.0°C - 65.0°C)
Mass milk * 58.0°C = 200g * 20.0°C
Mass milk = 4000g°C / 58.0°C
Mass milk =
68.97g of milk must be added
Verdadero o falso si un átomo presenta de 5 a 7 electrones en su nivel más extremo tenderá a perderlos?
Help guys please question 3 in picture ASAP pls
Answer:
1 Spinal fluid
2 Milk
3 Saliva
4 Urine
5 Gastric content
Explanation:
Hello there!
In this case, according to the given information, it turns out firstly necessary for us to calculate the pH of both gastric content and spinal fluid by using the following equations and works:
[tex]pH_{gastric}=-log(10^{-2})=2.0\\\\pH_{spinal}=14+log(10^{-6.6})=7.4[/tex]
Thus, we rank them as follows:
1 Spinal fluid
2 Milk
3 Saliva
4 Urine
5 Gastric content
Regards!
If you knew the volume of the solution containing NaCl(aq), determine how you would predict the mass of AlCl3(s) formed
Answer:
See explanation.
Explanation:
Hello there!
In this case, according to the given information, it turns out possible for us to realize that the NaCl solution must react with an aluminum-containing substance, say the hydroxide or any other salt, so that the following equation will take place:
[tex]3NaCl(aq)+Al^{3+}\rightarrow 3Na^+(aq)+AlCl_3(s)[/tex]
In such a way, given the volume of the NaCl solution, it must be necessary to know its concentration, in order to get moles of this salt, further use the 3:1 mole ratio of NaCl to AlCl3 and the molar mass of the latter (133.34 g/mol) in order to solve an stoichiometric setup like the following:
[tex]m_{AlCl_3}=V_{NaCl}*M_{NaCl}*\frac{1molAlCl_3}{3molNaCl} *\frac{133.34gAlCl_3}{1molAlCl_3}[/tex]
Besides, you must make sure the volume is in liters.
Best regards!
The decomposition of hydrogen peroxide was studied, and the following data were obtained at a particular temperature.Time (s) [H2O2] (mol/L)0 1.00120 ± 1 0.91300 ± 1 0.78600 ± 1 0.591200 ± 1 0.371800 ± 1 0.222400 ± 1 0.133000 ± 1 0.0823600 ± 1 0.050 Assuming that the rate= -delta [H2O2]/delta t determine the rate law, integrated rate law, and the value of the rate constant. Calculate [H2O2] at 4000. s after the start of the reaction.
Answer:
Explanation:
From the graphical diagram attached below; we can see the relationship between the concentration of [tex]H_2O_2[/tex] which declines exponentially in relation to the time and it obeys the equation: [tex]\mathtt{y = 0.9951 e^{-8\times 10^{-4}x}}[/tex]
This relates to the 1st order reaction rate, whereby:
The integrated rate law[tex]\mathtt{ [A] = [A]_o e^{-kt}}[/tex]
here:
[A] = reactant concentration at time (t)
[A]_o = initial concentration for the reactant
k = rate constant
As such, the order of the reaction is the first order
Rate constant [tex]\mathtt{k = 8\times 10^{-4} {s^{-1}}}[/tex]
Rate law [tex]\mathtt{= k[H_2O_2]}[/tex]
The integrated rate law [tex]\mathtt{[H_2O_2] = [H_2O_2]_oe^{-(8*10^{-4})t}}[/tex]
From the given table:
the initial concentration of [tex]H_2O_2[/tex] = 1.00 M
∴
We can determine the concentration of the reactant at 4000s by using the formula:
[tex]\mathtt{[H_2O_2] = [H_2O_2]_oe^{-8*10^{-4}(t)}}[/tex]
[tex]\mathtt{[H_2O_2] = (1.00\ M)*e^{-8*10^{-4}(4000)\ s}}[/tex]
[tex]\mathtt{[H_2O_2] =0.0407 \ M}[/tex]
Finally, at 4000s: the average rate is:
[tex]\mathtt{= (8*10^{-4} \ s^{-1})(4000 \ s) }\\ \\ \mathtt{ = 3.256 \times 10^{-5} \ M/s}[/tex]
You are given a solution containing a pair of enantiomers (A and B). Careful measurements show that the solution contains 98% A and 2% B. What is the ee of this solution
Answer:
ee = 96%
Explanation:
Enantiomeric excess, ee, is a way to express a mixture that is not enantiomerically pure. It is defined as 100 times the ratio between the differences of amounts of enantiomers and the total amunt. that is:
ee = |A-B|/ A+B * 100
ee = |98%-2%| / 98+2 * 100
ee = 96%In the picture this is my last question pls.
Answer:
Chromosomes and I think its too many
Explanation:
The diagram shows an experiment. damp litmus paper gas given off mixture of ammonium chloride and sodium hydroxide 1 heat What is the name of the gas and the final colour of the litmus paper? gas colour A ammonia blue B ammonia red с chlorine white D chlorine red plz guys help me
Answer:
The correct answer is - A. ammonia blue.
Explanation:
It is given that there is a mixture of ammonium chloride and sodium hydroxide and if we heat the Mixture of NH4Cl and NaOH then, the following reaction will take place-
NH4Cl (aq)+ NaOH (aq)==> NaCl (aq) + NH3 (g)+ H2O (l)
In this reaction, there is a release of NH3 gas which is absorbed on litmus paper. We know that NH3 gas is basic in nature and so it will turn litmus paper blue.
Thus, the correct answer would be - NH3 (ammonia ) and Blue
sound waves? like what they do.
Answer:
A sound wave is the pattern of disturbance caused by the movement of energy traveling through a medium (such as air, water, or any other liquid or solid matter) as it propagates away from the source of the sound. The source is some object that causes a vibration, such as a ringing telephone, or a person's vocal chords.
HEY. HOPE THIS HELPS♡
Phenols do not exhibit the same pka values as other alcohols; they are generally more acidic. Using the knowledge that hydrogen acidity is directly related to the stability of the anion formed, explain why phenol is more acidic than cyclohexane
Answer:
Phenols do not exhibit the same pka values as other alcohols;
They are generally more acidic.
Using the knowledge that hydrogen acidity is directly related to the stability of the anion formed, explain why phenol is more acidic than cyclohexane.
Explanation:
According to Bromsted=Lowry acid-base theory,
an acid is a substance that can release [tex]H^{+}[/tex] ions when dissolved in water.
So, acid is a proton donor.
If the conjugate base of an acid is more stable then, that acid is a strong acid.
In the case of phenol,
the phenoxide ion formed is stabilized by resonance.
[tex]C_6H_5OH -> C_6H_5O^- +H^+[/tex]
The resonance in phenoxide ion is shown below:
Whereas in the case of cyclohexanol resonance is not possible.
So, cyclohexanol is a weak acid compared to phenol.
Naturally occurring gallium is a mixture of isotopes
that contains 90.11% of Ga-69 (atomic mass = 68.93
u) and 9.89% of Ga-71 (atomic mass 70.92 u).
What is the average atomic mass of naturally
occurring gallium?
A) 69.93 amu
C) 69.50 amu
B) 69.12 amu
D) 69.00 amu
Write the equation showing the formation of a monosubstituted product when butane reacts with chlorine. Use molecular formulas for the organic compounds (C before H, halogen last) and the smallest possible integer coefficients.
Answer:
CH3CH2CH2CH3 + Cl2 --------> CH3CH2CH2CH2Cl + HCl
Explanation:
Alkanes react with halogens in the presence of light to yield alkyl halides. The degree of substitution increases as the reaction progresses. The reaction occurs by free radical mechanism.
The reaction between butane and chlorine molecule to yields a monosubstitution product occurs as follows;
CH3CH2CH2CH3 + Cl2 --------> CH3CH2CH2CH2Cl + HCl
Give the change in conditions required to go from a gas to a solid. Give the change in conditions required to go from a gas to a solid. Decrease temperature or reduce pressure. Increase temperature or reduce pressure. Increase temperature or increase pressure. Decrease temperature or increase pressure. None of the above.
Answer:
Decrease temperature or reduce pressure
The density of water is about 1.0 g/mL at room temperature. Briefly explain how the density of an aqueous solution at room temperature can be significantly less than 1.0 g/mL. Give an example of such a solution.
Answer:
The density of water is about 1.0 g/mL at room temperature.
Briefly explain how the density of an aqueous solution at room temperature can be significantly less than 1.0 g/mL.
Give an example of such a solution.
Explanation:
That means 1.0mL of water weighs ---- 1.0g
If any other aqueous solution which has mass less than 1.0g will have density less than 1.0g.
For example aqueous solution of sulfuric acid has density 0.98g/mL.
That means 1mL of sulfuric acid has mass 0.98g.
Dissolving gases or liquids in water whose density are less than that of water will result in an aqueous solution whose density is less than that of water, for example, sulfuric acid which has a density 0.98g/mL.
What is density of a substance?The density of a substance is the ratio of the mass to the volume of that substance.
Density measures compactness.
More compact substances are more dense.
The density of water is about 1.0 g/mL at room temperature.
This means that 1.0mL of water weighs 1.0g
1.0 mL of an aqueous solution whose mass is less than 1.0g will have density less than that of water.
Dissolving gases or liquids in water whose density are less than that of water will result in an aqueous solution whose density is less than that of water.
An example of an aqueous solution whose density is less than that of water is sulfuric acid which has a density 0.98g/mL.
Sulfuric acid is prepared by dissolving sulphur (vi) oxide, a gas, in water.
This means 1mL of sulfuric acid has mass 0.98g.
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A hard-water solution contains 4.8 g of calcium chloride. How much sodium phosphate in grams should be added to the solution to completely precipitate all of the calcium
Answer:
4.7 g
Explanation:
The reaction that takes place is:
3CaCl₂(aq) + 2Na₃PO₄(aq) → Ca₃(PO₄)₂(s) + 6NaCl(aq)First we convert 4.8 g of CaCl₂ into moles, using its molar mass:
4.8 g ÷ 110.98 g/mol = 0.0432 mol CaCl₂Then we convert CaCl₂ moles into Na₃PO₄ moles, using the stochiometric coefficients of the balanced reaction:
0.0432 mol CaCl₂ * [tex]\frac{2molNa_3PO_4}{3molCaCl_2}[/tex] = 0.0288 mol Na₃PO₄Finally we convert 0.0288 moles of Na₃PO₄ into grams, using its molar mass:
0.0288 mol Na₃PO₄ * 164 g/mol = 4.7 gAn ion has 38 protons, 36 electrons, and 40 neutrons, what us the elements symbol
The symbol of the element in which it's ion has 38 protons, 36 electrons, and 40 neutrons is ⁷⁸₃₈Sr
How do I determine the symbol of the element?To obtain the symbol of the element, we shall obtain the mass number of the element. This is shown below:
Proton = 38Neutron = 40Mass number = ?Mass number = Proton + Neutron
Mass number = 38 + 40
Mass number = 78
Finally, we shall determine the symbol of the element. Details below:
Proton = 38Atomic number (z) = Proton = 38Mass number (A) = 78Symol of element =?From the periodic table, the element with atomic number of 38 is Strontium.
Thus, the symbol of the element will be ⁷⁸₃₈Sr
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What is the pH of a solution whose hydronium ion [H20+] (or proton [H+1)
concentration is 7.6' 10-5 M?
Answer:
[tex]pH = - log(7.6 \times {10}^{ - 5} ) \\ pH = 4.12[/tex]
A 1.375 g sample of mannitol, a sugar found in seaweed, is burned completely in oxygen to give 1.993 g of carbon dioxide and 0.9519 g of water. The empirical formula of mannitol is
Answer:
[tex]C_3H_7O_3[/tex]
Explanation:
Hello there!
In this case, according to the given information, it turns out possible for us to infer that the empirical formula of mannitol contains carbon, hydrogen and oxygen, so that the first step is to calculate the moles of C and H contained in the CO2 and H2O, respectively, as the only sources of these two elements in the formula:
[tex]n_C=1.993gCO_2*\frac{1molCO_2}{44.01gCO_2}*\frac{1molC}{1molCO_2} =0.0453molC\\\\n_H=0.9519gH_2O*\frac{1molH_2O}{18.02gH_2O}*\frac{2molH}{1molH_2O} =0.106molH[/tex]
Next, we calculate the grams and moles of O by subtracting the mass of C and H from the mass of the sample:
[tex]m_O=1.375g-0.0453molC*\frac{12gC}{1molC}-0.106molH*\frac{1.01gH}{1molH}=0.724gO\\\\n_O=0.724gO*\frac{1molO}{16.0gO} =0.0453molO[/tex]
Finally, we divide the moles of C, H and O by 0.0453 as the fewest moles of both C and O to find the mole ratios in the formula:
[tex]C:\frac{0.0453mol}{0.0453mol} =1\\\\H:\frac{0.106mol}{0.0453mol} =2.34\\\\O:\frac{0.0453mol}{0.0453mol} =1[/tex]
To get:
[tex]CH_{2.34}O[/tex]
Which must be multiplied by 3 to get whole numbers for all the subscripts, and therefore obtain:
[tex]C_3H_7O_3[/tex]
Regards!
Studying and got stuck if someone can help me.
Answer:
Ph level 0-7 is a acid
ph level 7-14 is base
bases turn paper blue
acids dissolve metal
acids contain hydrogen ions
Explanation:
I dont know the last one all I know that they become neutral when acids and bases are mixed.
Write the precipitation reaction for cobalt(II) hydroxide in aqueous solution: Be sure to specify the state of each reactant and product.
Answer:
The equation for the precipitation reaction of cobalt (ii) hydroxide is given below:
CoSO₄ (aq) + NaOH (aq) ----> Co(OH)₂ (s) + Na₂SO₄ (aq)
Explanation:
Cobalt (ii) hydroxide is an inorganic compound consisting of cobalt (ii) ions, Co²+ and hydroxide ions, OH-. It is insoluble in water and the pure form known as the beta form is a pink-coloured solid. The impure form which incorporates other anions in its molecular structure is blue in colour and is ustable.
Cobalt (ii) hydroxide is formed as precipitate when an alkaline metallic hydroxide such as sodium hydroxide is mixed with an aqueous cobalt (ii) salt such as cobalt (ii) sulfate. The equation for the precipitation reaction of cobalt (ii) hydroxide is given below:
CoSO₄ (aq) + NaOH (aq) ----> Co(OH)₂ (s) + Na₂SO₄ (aq)
Being a basic hydroxide, cobalt (ii) hydroxide neutralizes acids to form cobalt (ii) salts and water. For example: Co(OH)₂ (s) + H₂SO₄ (aq) ---> CoSO₄ (aq) + H₂O
Thus, cobalt (ii) hydroxide is soluble in acids.
Cobalt(II) hydroxide is used mostly as a drying agent for paints, varnishes, and inks. It is also useful in the preparation of other cobalt compounds.
In the electrolysis of water, how long will it take to produce 75.00 L of H2 at 1.0 atm and 273 K using an electrolytic cell through which the current is 205.0 mA
answer is 2546 h
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Washes and extractions are both techniques that use a separatory funnel to separate liquid layers. However, washes and extractions have differences. Determine whether each statement applies to washes or extractions.
Leaves impurities in their starting layer Choose...
Moves impurities from one layer to another Choose...
Moves desired compound from one layer to another Choose...
Often involves a reaction in one of the layers Choose...
Leaves desired compound in its starting layer Choose...
Answer:
Leaves impurities in their starting layer - Extraction Moves impurities from one layer to another - Wash Moves desired compound from one layer to another - Extraction Often involves a reaction in one of the layers - Extraction Leaves desired compound in its starting layer - WashExplanation:
Both extraction and wash are technical materials separation processes. Both seek to carry out a separation of liquid-liquid, through the relationship between solvent and solute present in this solution. Both use a separation funnel and are very similar processes where the main difference is the purpose that each one seeks to exercise. The extraction causes the dissolution of the material that the researcher wants to leave behind. this process leaves impurities in the initial solution layer and moves the researcher's desired compound to the second layer of solution. A chemical reaction can take place during this process.
A wash, on the other hand, dissolves all impurities from the solution and extracts the compound desired by the researcher. Therefore, we can conclude that during this process the impurities are moved from one layer to another in the solution until it is discarded from the funnel, leaving the desired compound in the initial layer.
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Name the following alkane molecule:
Answer:
5–bromo–9–chlorodecane
Explanation:
To name the compound given above, the following must be obtained:
1. The longest continuous carbon chain. This gives the parent name of the compound.
2. The substituent group attached to the compound.
3. Position of the substituent group.
4. Combine the above to obtain the name.
Now, we shall determine the name of the compound as follow:
1. The longest continuous carbon chain is 10. Thus, the parent name of the compound is decane.
2. The substituent groups attached to the compound are:
I. Bromine (Br) => Bromo
II. Chlorine (Cl) => Chloro
3. The position of the substituent groups are:
I. Br => carbon 5
II. Cl => carbon 9
NOTE: numbering is done alphabetically.
4. Therefore, the name of the compound is:
5–bromo–9–chlorodecane
Answer:
A.
Explanation:
I chose this answer and it was correct ♀️
Ammonia burns in the presence of a copper catalyst to form nitrogen gas. 4 NH3(g) + 3 O2(g) → 2 N2(g) + 6 H2O(g) ΔΗ = -1267 kJ What is the enthalpy change to burn 38.4 g of ammonia?
Answer:
-713 kJ
Explanation:
Step 1: Write the balaned thermochemical equation
4 NH₃(g) + 3 O₂(g) → 2 N₂(g) + 6 H₂O(g) ΔΗ = -1267 kJ
Step 2: Calculate the moles corresponding to 38.4 g of NH₃
The molar mass of NH₃ is 17.03 g/mol.
38.4 g × 1 mol/17.03 g = 2.25 mol
Step 3: Calculate the enthalpy change to burn 2.25 mol of ammonia
According to the thermochemical equation, 1267 kJ are released per 4 moles of ammonia that react.
2.25 mol × (-1267 kJ/4 mol) = -713 kJ
given two equations representing reactions: which type of reaction is represented by each of these equations?
Answer:
Equation 1 - nuclear fission
Equation 2 - nuclear fusion
Explanation:
Nuclear fission is a reaction in which a large nucleus is split into smaller nuclei when it is bombarded by neutrons. The process produces more neutrons to continue the chain reaction. This is clearly depicted in equation 1 as shown in the question.
Nuclear fusion is a reaction in which two light nuclei combine in order to form a larger nuclei. This is clearly depicted in equation 2 as shown in the question.
In the first reaction, a neutron is released, and in the second a helium atom is released. The given two equations represent nuclear fission and fusion.
What are nuclear reactions?A nuclear reaction is a reaction that involves the nuclei of the atom and the absorption and release of energy. In the first reaction, a big nucleus is split by the neutron bombardment into smaller nuclei.
In the second reaction the process of nuclear fusion, two nuclei combine into a single larger nucleus that is shown as:
₁¹H+ ²₁H → ³₂He
Therefore, nuclear fission and fusion are represented by each of these equations.
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Classify each of the following as a Strong acid (sa) or a Weak acid (wa) and indicate how each should be written in aqueous solution.
1. hydrobromic acid
2. hydrochloric acid
3. carbonic acid
Write a net ionic equation for the reaction that occurs when aqueous solutions of hydrochloric acid and barium hydroxide are combined.
Answer:
A. 1. Strong acid (sa): Hydrobromic acid: HBr (aq)
2. Strong acid (sa); Hydrochloric acid: HCl (aq)
3. Weak acid (wa); Carbonic acid: H₂CO₃ (aq)
B. H+ (aq) + OH- (aq) ----> H₂O (l)
Explanation:
Strong acids are which ionize completely in aqueous solution into hydrogen ions and the corresponding anion. Examples of strong acids include hydrobromic acid, hydrochloric acid, tetraoxosulfate (vi) acid.
The ionization of hdyrobromic and hydrochloric acids in aqueous solution is given below:
1. Hydrobromic acid: HBr (aq) ----> H+ (aq) + Br- (aq)
Hydrobromic acid in aqueous solution ionizes completely into hydrogen ions and bromide ions
2. Hydrochloric acid: HCl (aq) ----> H+ (aq) + Cl- (aq)
Hydrochloric acid in aqueous solution ionizes completely into hydrogen ions and chloride ions
Weak acids are acids which ionizes only partially in aqueous solutions to hydrogen ions and the corresponding anions. Examples of weak acids are carbonic acid and ethanoic acid. The ionization of carbonic acid in aqueous solution is shown below:
3. Carbonic acid: H₂CO₃ (aq) ⇄ 2 H+ (aq) + CO₃²- (aq)
Carbonic acid ionizes partially only to give hydrogen ions and trioxocarbonate (iv) ions. The unionized acid exists in equilibrium with the ions produced by the partial ionization of the acid.
Part B:
The reaction between hydrochloric acid and barium hydroxide is a neutralization reaction producing barium chloride salt and water.
The net ionic equation of the neutralization reaction is given below :
H+ (aq) + OH- (aq) ----> H₂O (l)
Why does glucose and acentic acid have the same empirical formula
Answer:
Examples. Glucose (C6H12O6), ribose (C5H10O5), Acetic acid (C2H4O2), and formaldehyde (CH2O) all have different molecular formulas but the same empirical formula: CH2O.
Explanation:In chemistry, the empirical formula of a chemical compound is the simplest positive integer ratio of atoms present in a compound.
What is the mass of 6 atom(s) of copper in grams?
Answer:
6.33×10¯²² g
Explanation:
From the question given above, the following data were obtained:
Number of atoms = 6 atoms
Mass of copper (Cu) =?
From Avogadro's hypothesis, we understood that:
6.02×10²³ atoms = 1 mole of Cu
But 1 mole of Cu = 63.5 g
Thus,
6.02×10²³ atoms = 63.5 g of Cu
Finally, we shall determine the mass of 6 atoms of copper. This can be obtained as illustrated below:
6.02×10²³ atoms = 63.5 g of Cu
Therefore,
6 atoms = (6 × 63.5) / 6.02×10²³
6 atoms = 6.33×10¯²² g of Cu
Therefore, the mass of 6 atoms of copper is 6.33×10¯²² g.