Answer:
its d
Explanation:
Select the correct answer.
An object's density equals its mass divided by its volume. If a certain object has a mass of 125.0 grams and a volume of 25 ml, what is its density
expressed to the correct number of significant figures?
OA 5.000 g/mL
OB. 5.0 g/ml
OC. 5.00 g/ml
OD. 5 g/mL
Answer:
I think its B
Explanation:
math
Cho hỗn hợp hai kim loại Na, Mg (lấy dự) tác dụng với dung dịch HSO4. Biết lượng khí H2 thoát ra bằng 5% khối lượng dung dịch H2SO4 Tính nồng độ phần trăm của dung dịch H2SO4?
Answer:
As it is given that the initial concentration of sulfuric acid is 0.010 M.
Hence, the ICE table for first dissociation of sulfuric acid is as follows.
Initial: 0.010 0 0
Change: -0.010 +0.010 +0.010
Equilibrium: 0 0.010 0.010
When second dissociation of sulfuric acid occurs which is partial then the ICE table will be as follows.
Initial: 0.010 0 0.010
Change: -x +x +x
Equilibrium: 0.010 - x x 0.010 + x
Since, it is given that . Hence, formula for is as follows.
x = 0.0045
Hence, by using the equilibrium concentrations from the table and value of x we get the following.
= x,
= 0.0045 M
= 0.010 - x
= 0.010 - 0.0045
= 0.0055 M
= 0.010 + x
= 0.010 + 0.0045
= 0.0145 M
Explanation:
13. The attraction between water molecules and an Na+
ion or a Cl- ion occurs because water molecules are
A) linear
B) symmetrical
C) polar
D) nonpolar
Answer:
C) Polar
Explanation:
The correct answer is polar
The attraction of sodium and chloride ions by the water is mediated by the polar nature of water. Thus, option C is correct.
What is polarity?The polarity is given as the formation of the partial positive and negative charge over the species in the ionization process.
Water molecule is having one hydrogen bounded with 2 oxygen atoms, and oxygen being more electronegative develops a partial negative charge, while hydrogen develops a partial positive charge.
The positive charge hydrogen and the negative charge oxygen attracts the opposite charge sodium and chloride ions. Thus, the attraction is mediated due to the polar nature of water. Hence, option C is correct.
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Unknown A melts at 113- 114oC. Known compounds 3-Nitroaniline and 4-Nitrophenol both melt at 112-114 oC. If A is mixed with 3-Nitroaniline and the melting point becomes broad and depressed, what must A be __________A) 3-Nitroaniline B) 4-Nitrophenol C) Both
Answer:
C) Both
Explanation:
Whenever we mix any pure form of a compound with some other form of a compound which is not in the other standard pure state, this results in the melting point of mixture to get dispersed and it becomes broad form.
Thus, when a known compound of 3-Nitroaniline mixes with both 3-Nitroaniline and 4-Nitrophenol, the melting point of the compound becomes depressed and board.
Thus the correct option is (C).
Given the following values for the change in enthalpy (deltaH) and entropy (deltaS), which of the following processes can occur at 298 K without violating the second Law of Thermodynamics?
(a) DeltaH = -84 kj mol-2 (-20 kcal mol-1), DeltaS = +125j mol-2K-1)(+30 cal mol-1 K-1)
(b) DeltaH = -84 kj mol-2 (-20 kcal mol-1), DeltaS = -125j mol-2K-1)(-30 cal mol-1 K-1)
(c) DeltaH = +84 kj mol-2 (+20 kcal mol-1), DeltaS = +125j mol-2K-1)(+30 cal mol-1 K-1)
(d) DeltaH = +84 kj mol-2 (+20 kcal mol-1), DeltaS = +125j mol-2K-1)(-30 cal mol-1 K-1)
Answer:
Option A and B
Explanation:
(a) DeltaH = -84 kj mol-2 (-20 kcal mol-1), DeltaS = +125j mol-2K-1)(+30 cal mol-1 K-1)
Delta G = Delta H – T * DS
Substituting the given values, we get –
Delta G = -84 -298 *(125/1000) = -121.25 KJ/mol
Delta G is negative hence the process is spontaneous and will not violate the second law of thermodynamics
(b) DeltaH = -84 kj mol-2 (-20 kcal mol-1), DeltaS = -125j mol-2K-1)(-30 cal mol-1 K-1)
Delta G =-84 -298 *(-125/1000) = -46.75 KJ/mol
Delta G is negative hence the process is spontaneous and will not violate the second law of thermodynamics
(c) DeltaH = +84 kj mol-2 (+20 kcal mol-1), DeltaS = +125j mol-2K-1)(+30 cal mol-1 K-1)
Delta G = 84 -298 *(125/1000) = +46.75 KJ/mol
Delta G is positive hence the process is non-spontaneous and will violate the second law of thermodynamics
(d) DeltaH = +84 kj mol-2 (+20 kcal mol-1), DeltaS = +125j mol-2K-1)(-30 cal mol-1 K-1)
Delta G = 84 -298 *(-125/1000) = + 121.25 KJ/mol
Delta G is positive hence the process is non-spontaneous and will violate the second law of thermodynamics
Consider the balanced chemical equation below.
2 A ⟶ C + 4 D
How many moles of D would be produced if 5 moles of A were used?
Answer:
Yes indeed this is correct because the equation just makes sense
Explanation:
What does Etching , Stratches and sample size impact hardness results of metals
Answer:
Etching is used to reveal the microstructure of the metal through selective chemical attack. It also removes the thin, highly deformed layer introduced during grinding and polishing. ... The specimen is etched using a reagent.
Explanation:
hope it was helpful.....
Predict the products from theses reaction, and balance the equations. Include phase symbols.
Reaction : K(s)+Cl2(g)⟶
Reaction :Cu(s)+O2(g)⟶
Answer:
2 K(s) + Cl₂(g) ⟶ 2 KCl(s)
2 Cu(s) + O₂(g) ⟶ 2 CuO(s)
Explanation:
Both reactions are synthesis reactions (two substances combine to form another).
Reaction: K(s) + Cl₂(g) ⟶
The product is the binary salt KCl. The balanced chemical equation is:
2 K(s) + Cl₂(g) ⟶ 2 KCl(s)
Reaction: Cu(s) + O₂(g) ⟶
The most likely product is the metal oxide CuO. The balanced chemical equation is:
2 Cu(s) + O₂(g) ⟶ 2 CuO(s)
Identical wire loops are dipped into Liquid X and Liquid Y, so that a film of liquid forms across the loops (like the bubble solution on a child's bubble blowing wand). The width of each loop is increased slowly and the forces FX and FY needed to make the loops 5% wider are measured.
a. FX will be greater than F Y
b. FX will be less than FY
c. FX will be equal to FY
d. It's impossible to predict whether F X or FY will be greater without more information.
Answer:
a.
Explanation:
Assuming that Liquid X is considered to possess a greater viscosity as well as higher surface tension than liquid Y. Then, liquid X will tend to harbour more pressure inside the liquid.
In addition to that, the greater the surface tension, the greater the force required to expand the liquid's surface area.
This in turn makes the force required to make the loop 5% wider to be greater in FX rather than FY.
Thus, option a is the correct answer.
Calculate [H3O+] and [OH−] for each of the following solutions at 25 ∘C given the pH.
pH= 2.89
Answer: The value of [tex][H_{3}O^{+}][/tex] is 0.0012 M and [tex][OH^{-}][/tex] is [tex]1.02 \times 10^{-14}[/tex].
Explanation:
pH is the negative logarithm of concentration of hydrogen ion.
It is given that pH is 2.89. So, the value of concentration of hydrogen ions is calculated as follows.
[tex]pH = - log [H^{+}]\\2.89 = - log [H^{+}]\\conc. H^{+} = 0.0012 M[/tex]
The relation between pH and pOH value is as follows.
pH + pOH = 14
0.0012 + pOH = 14
pOH = 14 - 0.0012 = 13.99
Now, pOH is the negative logarithm of concentration of hydroxide ions.
Hence, [tex][OH^{-}][/tex] is calculated as follows.
[tex]pOH = - log [OH^{-}]\\13.99 = - log [OH^{-}]\\conc. OH^{-} = 1.02 \times 10^{-14} M[/tex]
Thus, we can conclude that the value of [tex][H_{3}O^{+}][/tex] is 0.0012 M and [tex][OH^{-}][/tex] is [tex]1.02 \times 10^{-14}[/tex].
Solids that have particles arranged in a regular, repeating patterns are known as crystalline solids.
True or False
Answer: The answer is false
Explanation:
they are arranged in a structure
called a crystalline.
A solution of acetic acid that has a concentration of 0.10 moles per liter has a pH of 2.87. What is the likely pH of a 0.10 mole per liter solution of the conjugate base sodium acetate?
A. 8.97
B. 1.00
C. 2.87
D. 4.74
E. 13.00
Answer: The correct option is A) 8.97
Explanation:
To calculate the [tex]K_b[/tex] of a reaction, we use the equation:
[tex]K_a\times K_b=10^{-14}[/tex]
where,
[tex]K_a[/tex] = acid dissociation constant of acetic acid = [tex]1.86\times 10^{-5}[/tex]
[tex]K_b[/tex] = base dissociation constant
Putting values in above equation, we get:
[tex](1.86\times 10^{-5})\times K_b=10^{-14}\\\\K_b=\frac{10^{-14}}{1.86\times 10^{-5}}=5.37\times 10^{-10}[/tex]
To calculate the hydroxide ion concentration of conjugate base, we use the equation:
[tex][OH^-]=\sqrt{K_b\times \text{[Conjugate base]}}[/tex]
where,
[Conjugate base] = 0.10 M
Putting values in above equation, we get:
[tex][OH^-]=\sqrt{(5.37\times 10^{-10})\times 0.1}[/tex]
[tex][OH^-]=7.33\times 10^{-6}[/tex]
To calculate the pOH of the solution, we use the equation:
[tex]pOH=-\log [OH^-][/tex]
[tex]pOH=-\log (7.33\times 10^{-6})[/tex]
[tex]pOH=5.03[/tex]
To calculate the pH of the solution, we use the equation:
pH + pOH = 14
pH + 5.03 = 14
pH = (14 - 5.03) = 8.97
Hence, the correct option is A) 8.97
How is the atomic mass unit found
Answer:
yo its jess bregoli
your answer is given below
(◠‿◕)
An atomic mass unit is defined as a mass equal to one twelfth the mass of an atom of carbon-12. The mass of any isotope of any element is expressed in relation to the carbon-12 standard. For example, one atom of helium-4 has a mass of 4.0026 amu. An atom of sulfur-32 has a mass of 31.972 amu.
What is the pCu of the resulting solution if 20.00 mL of 0.08 M EDTA (H4Y) is added to 15.00 mL of 0.10 M CuSO4 and buffered at pH 10? The Kf’ for complex CuY2- is 2.21 x 1018
Answer:
The answer is "5.4".
Explanation:
[tex]BoH + HCL =BCL +H_2o \\\\At eq \\\\N_1V_1=N_2V_2 \\\\v_2=20 \ ml\\\\[BCL]=\frac{20 \times 0.08}{20+20}=0.04\\\\pH = \frac{1}{2} [pkw - pk_b - \log e]\\\\pk_b = 2 pH - Pkw + \Log C\\\\pK_b=5.4[/tex]
Give reason: The maximum covalence of boron is 4.
Answer:
true
Explanation:
Answer:
true
Explanation:
How many moles of water are produced if 3.30 moles of N20 is
produced? NH4NO3 --> N20 + 2 H2O (mole to mole conversion) 1 step
Answer:
The netto reaction equation is:
2 OH- + 2H+ = 2 H2O
So the answer is 2 moles.
GC-mass spectrometry is used to find the ________ of each compound in a ________. Group of answer choices none of these molecular formula, mixture of compounds molecular weight, mixture of compounds B and C molecular formula, mixture of alkanes
Answer:
mixture of compounds molecular weight
Explanation:
Gas Chromatography-mass spectrometry is used to find the mixture of compounds of each compound in a molecular weight. The Gas Chromatography also known as Mass Spectrometry (GC/MS) is an instrument that is used to separate chemical mixtures and identifies the components at a molecular level. It is one of the most accurate tools used for analyzing samples of the environment.
Calculate the concentration of a solution with 0.8g of NaCl in 280mL of water.
Answer: The molarity of NaCl solution is 0.0489 M
Explanation:
Molarity is defined as the amount of solute expressed in the number of moles present per liter of solution. The units of molarity are mol/L. The formula used to calculate molarity:
[tex]\text{Molarity of solution}=\frac{\text{Given mass of solute}\times 1000}{\text{Molar mass of solute}\times \text{Volume of solution (mL)}}[/tex] .....(1)
We are given:
Given mass of NaCl = 0.8 g
Molar mass of NaCl = 58.44 g/mol
Volume of the solution = 280 mL
Putting values in equation 1, we get:
[tex]\text{Molarity of solution}=\frac{0.8\times 1000}{58.44\times 280}\\\\\text{Molarity of solution}=0.0489M[/tex]
Hence, the molarity of NaCl solution is 0.0489 M
A 14.570 g sample of CaCl2 was added to 12.285 g of K2CO3 and mixed in water. A 3.494 g yield of CaCO3 was obtained.
What is the limiting reagent?
-CaCO3
-K2CO3
-CaCl2
Calculate the percent yield of CaCO3.
yield of CaCO3= %
Answer:
Limiting reagent is the potassium carbonate.
Percent yield of calcium carbonate is: 39.3 %
Explanation:
The reaction is:
CaCl₂ + K₂CO₃ → CaCO₃ + 2KCl
Formula for percent yield is:
(Produced yield / Thoeretical yield) . 100
Firstly we determine the moles of each reactant, in order to say what is the limiting reagent: ratio is 1:1.
1 mol of chloride need 1 mol of carbonate.
14.570 g . 1 mol /110.98 g = 0.131 moles of CaCl₂
12.285 g . 1 mol / 138.2g = 0.0889 moles of carbonate.
Limiting reagent is carbonate. For 0.131 moles of CaCl₂ we need the same amount of carbonate and we have less moles.
Ratio is also 1:1, with calcium carbonate.
1 mol of potassium carbonate produces 1 mol of calcium carbonate
then, 0.0889 moles will produce the same amount of CaCO₃
We convert moles to mass: 0.0889 mol . 100.08g /mol = 8.89 g
That's the theoretical yield; to find the percent yield:
(3.494 g / 8.89g) . 100 = 39.3%
During seafloor spreading, what kind of new earth forms?
Answer:
This bubbled-up magma is cooled by frigid seawater to form igneous rock. This rock (basalt) becomes a new part of Earth's crust. Seafloor spreading occurs along mid-ocean ridges—large mountain ranges rising from the ocean floor.
Explanation:
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In the periodic table,
have common properties,
periods
both groups and periods
neither groups nor periods
groups
Answer:
both groups and periods
Answer:
groups
Explanation:
Elements in the same group have similar chemical properties because they have the same number of outer electrons and the same valency
When the following oxidation-reduction reaction in acidic solution is balanced, what is the
lowest whole-number coefficient for Rb+ (aq)?
Rb(s) + Sr2+ (aq) → Rb+(aq) + Sr(s)
Answer:
2Rb(s) + Sr^+(aq) → 2Rb^+ (aq) + Sr(s)
Explanation:
In a redox reaction, we must ensure that the number of electrons gained equals the number of electrons lost in the reduction and oxidation half reaction equations respectively.
Having that in mind;
Oxidation half reaction;
2Rb(s) ---->2Rb^+(aq) + 2e
Reduction half equation;
Sr^2+(aq) + 2e---> Sr(s)
Hence, the overall redox reaction equation is;
2Rb(s) + Sr^+(aq) → 2Rb^+ (aq) + Sr(s)
Which atom has the electron configuration 1s²2s²2p⁶3s²3p⁶4s²3d¹⁰4p⁶5s²4d²? and 1s²2s²2p⁶3s²3p⁶3d⁷4s²?
identify the two functional groups in the following compound
Answer:
D. amine and alcohol
Explanation:
Organic compounds are identified using the functional group they contain. The functional group defines their peculiarity and chemical identity. For example, alkenes are identified by a double bond functional group (=), alcohols are identified by an hydroxyl functional group (OH) etc.
According to this question, a compound was given as an attached image. The compound posseses:
- an hydroxyl group (OH) indicating that it has an ALCOHOL functional group
- an N-H group indicating that it has an amine functional group
An ether and alkene are formed as by products in this reaction. draw the structures of these by-products and give mechanisms for their formation
Answer:
sim eu também preciso desta respota
An ether and alkene are formed as by products in the reaction which is a electrophilic addition reaction.
What is electrophilic addition reaction?An addition reaction known as an electrophilic addition reaction occurs when a chemical molecule having a double or triple bond has one of its bonds broken and two new bonds are formed. The interconversion of C=C and CC into a variety of significant functional groups, such as alkyl halides and alcohols, is made possible via the key.
The following describes the general mechanism: Hydrogen bromide produces an electrophile, H+, which attacks the double bond to create a carbocation. The production of ions is dominated by secondary carbocation because it is more stable than primary carbocation.
Thus, an ether and alkene are formed as by products in the reaction which is a electrophilic addition reaction.
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This question is concerned with the following oxides
• Sulfur dioxide
• Carbon monoxide
• Lithium oxide
• Aluminum (III) oxide
Which of the above oxides will not react with hydrochloric acid but will react with aqueous
sodium hydroxide?
Answer:
hi I used your code you got it
what is a property of every mixture
Explanation:
can u post a picture of the question ?
Assume you find four bottles in an empty laboratory, each containing a liquid. The labels that were on these bottles have fallen off and are strewn about the bench top. Therefore, you know the contents of the four bottles, but do not know which bottle belonged to which compound. The names on the labels are given below:
trans-1,2-dichloroethylene,
cis-1,2-dichloroethylene,
cyclooctane,
and acetic acid.
Without determining the boiling point, would you be able to identify the contents of each bottle using solubility and polarity (with H2O) information? Explain your reasoning.
Answer:
No, I can not identify the contents of each bottle using solubility and polarity (with H2O) information
Explanation:
While it is true that polar substances dissolve in water and nonpolar substances do not dissolve in water, the task here is to specifically identify the contents of each of the bottles.
Solubility in water can not tell us exactly what liquid is which substance. For instance, trans-1,2-dichloroethylene, cis-1,2-dichloroethylene and cyclooctane are all insoluble in water. The fact that they do not dissolve in water does not tell us which liquid is which compound.
Even though acetic acid is miscible with water, it is not a conclusive prove that the liquid is acetic acid since other polar organic compounds are also miscible in water.
It is only by determining the boiling point of each substance that I can conclusively identify the contents of each bottle since boiling point is an intrinsic property of substances.
An aqueous solution containing 5.72 g
of lead(II) nitrate is added to an aqueous solution containing 5.85 g
of potassium chloride. The reaction goes to completion, but some was lost in the process of washing and drying the precipitate. The percent yield for the reaction is 81.9%
. How many grams of precipitate is recovered? How many grams of the excess reactant remain? Assume the reaction goes to completion.
Answer:
3.93g are recovered
Explanation:
Pb(NO3)2 reacts with KCl as follows:
Pb(NO3)2 + 2KCl → 2KNO3 + PbCl2
To solve this question we need to find the moles of each reactant in order to find the limiting reactant:
Moles Pb(NO3)2 -Molar mass: 331.2 g/mol-
5.72g * (1mol/331.2g) = 0.01727 moles
Mole KCl -Molar mass: 74.5513g/mol-
5.85g * (1mol/74.5513g) = 0.07847 moles
For a complete reaction of 0.07847 moles of KCl are required:
0.07847 moles KCl * (1mol Pb(NO3)2 / 2mol KCl) = 0.03923 moles Pb(NO3)2
As there are just 0.01727 moles, Pb(NO3)2 is limiting reactant. Assuming 100% of yield:
Moles PbCl2 = Moles Pb(NO3)2
Mass PbCl2 -Molar mass: 278.1g/mol-
0.01727 moles * (278.1g / mol) = 4.80g
As percent yield is 81.9% = 0.819, the mass of PbCl2 recovered was:
4.80g * 0.819 = 3.93g are recovered
In Denver, Colorado the elevation is about 5,280 feet above sea level. Explain what potential effects this may have on the solubility of a gaseous solute in a liquid solution.
Answer:
The solubility of the gaseous solute decreases
Explanation:
As we know, pressure decreases with altitude. This means that, at higher altitudes, the pressure is much lower than it is at sea level.
The solubility of a gas increases with increase in pressure and decreases with decrease in pressure.
Hence, in Denver, Colorado where the elevation is about 5,280 feet above sea level, a gaseous solute is less soluble than it is at sea level due to the lower pressure at such high altitude.