Answer:
% NiCl2 = 24.13%
% water = 78.57%
Explanation:
Mass percentage = mass of solute/mass of solution × 100
According to this question, a solution contains 159 g of NiCl2 in 500 g of water. Hence, mass of the solution is calculated as follows:
Mass of solution = 159g + 500g
Mass of solution = 659g
Therefore;
A) % Mass of NiCl2 in solution = mass of NiCl2/mass of solution × 100
% Mass of NiCl2 in solution = 159/659 × 100
% Mass of NiCl2 in solution = 0.2413 × 100
= 24.13%
B) % Mass of water in solution = mass of water/mass of solution × 100
% Mass of water in solution = 500/659 × 100
% Mass of water in solution = 0.7587 × 100
% Mass of water in solution = 75.87%
2- . the number of waves in n *10 bohr's orbit are
Wet helium gas is placed into a balloon at 24.4 degrees Celsius and a pressure of 765.3 mm Hg. What volume (in L) does the dry gas occupy if the water vapor pressure is 24.3 torr and the mass of dried helium gas in the balloon is 0.498 g
Answer:
Hence the Volume of Gas = 3.04 L.
Explanation:
pressure of dry gas = 765.3 - 24.3 = 741 mmhg
Temperature of gas = 24.4+273.15 = 297.55 k
No of mol of gas = 0.498/4 = 0.1245 mol
R = gas constant = 0.0821 l.atm.k-1.mol-1
From ideal-gas equation
PV = nRT
(741/760) x v = 0.1245 x 0.0821 x 297.55
V = Volume of Gas = 3.04 L
A wavelength of 489.2 nm is observed in a hydrogen spectrum for a transition that ends in the nf level of the Balmer series. What was ni for the initial level of the electron
Answer:
[tex]n_1=4[/tex]
Explanation:
From the question we are told that:
Wavelength [tex]\lambda=489.2 nm =>4.86*10^{-7}[/tex]
nf level= Balmer series
nf level= 2
Generally the equation for Wavelength is mathematically given by
[tex]\frac{1}{\lambda}=R[\frac{1}{nf^2}-\frac{1}{n_1^2}][/tex]
Where
[tex]R=Rydberg Constant[/tex]
[tex]R=1.097*10^7[/tex]
Therefore
[tex]\frac{1}{4.86*10^{-7}}=1.097*10^7[\frac{1}{2^2}-\frac{1}{n_1^2}][/tex]
[tex]n_1=4.0021[/tex]
[tex]n_1=4[/tex]
convert 14.72 kg to ____ mg
Answer:
14720000
Explanation:
1 kg = 1000000 mg
14.72 kg = 14.72 x 1000000
=14720000
Please Mark me brainliest
Sodium acetate
NaC2H3O2
SC2H3O2
Na2C2H3O2
Answer:
Sodium acetate is NaC2H3O2
Answer:
The answer is A for the lazy people.
Balance the following equations and write the corresponding ionic and net ionic equations (if appropriate):
a. CH3COOH(aq) + KOH(aq) →
b. H2CO3(aq) + NaOH(aq) →
c. HNO3(aq) + Ba(OH)2(aq) →
Explanation:
here are your dissolutions
To calculate the atoms of an element in a given molecule, we need to multiply stoichiometry by the number that is written on the foot of that element. Therefore, the balanced equation are
CH[tex]_3[/tex]COOH + KOH [tex]\rightarrow[/tex]CH[tex]_3[/tex]COOK + H[tex]_2[/tex]O
H[tex]_2[/tex]CO[tex]_3[/tex] (aq) + 2 NaOH(aq) [tex]\rightarrow[/tex]Na[tex]_2[/tex]CO[tex]_3[/tex](aq) + 2 H[tex]_2[/tex]O
HNO[tex]_3[/tex] + Ba(OH)[tex]_2[/tex][tex]\rightarrow[/tex]Ba(NO[tex]_3[/tex])[tex]_2[/tex]+ H[tex]_2[/tex]O
What is Balanced equation?Balanced equation is the one in which the total number of atoms of a species on reactant side is equal to the total number of atoms on product side. The mass of the overall reaction should be conserved. There are so many types of chemical reaction reaction like combination reaction, displacement reaction.
The other characteristic of balanced reaction is that physical state should be written with each compound or molecule on reactant and product side. Physical state should be written in brackets. s means solid, l means liquid, g means gas.
The balanced equation can be written as
CH[tex]_3[/tex]COOH + KOH [tex]\rightarrow[/tex]CH[tex]_3[/tex]COOK + H[tex]_2[/tex]O
H[tex]_2[/tex]CO[tex]_3[/tex] (aq) + 2 NaOH(aq) [tex]\rightarrow[/tex]Na[tex]_2[/tex]CO[tex]_3[/tex](aq) + 2 H[tex]_2[/tex]O
HNO[tex]_3[/tex] + Ba(OH)[tex]_2[/tex][tex]\rightarrow[/tex]Ba(NO[tex]_3[/tex])[tex]_2[/tex]+ H[tex]_2[/tex]O
Therefore, the balanced equation are
CH[tex]_3[/tex]COOH + KOH [tex]\rightarrow[/tex]CH[tex]_3[/tex]COOK + H[tex]_2[/tex]O
H[tex]_2[/tex]CO[tex]_3[/tex] (aq) + 2 NaOH(aq) [tex]\rightarrow[/tex]Na[tex]_2[/tex]CO[tex]_3[/tex](aq) + 2 H[tex]_2[/tex]O
HNO[tex]_3[/tex] + Ba(OH)[tex]_2[/tex][tex]\rightarrow[/tex]Ba(NO[tex]_3[/tex])[tex]_2[/tex]+ H[tex]_2[/tex]O
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Methyl pentanoate condensed structural formula
Answer:
C6H12O2 is the formula for Methyl pentanoate
A saturated solution of potassium iodide contains, in each 100 mL, 100 g of potassium iodide. The solubility of potassium iodide is 1 g in 0.7 mL of water. Calculate the specific gravity of the saturated solution
Answer:
Specific gravity of the saturated solution is 2
Explanation:
The specific gravity is defined as the ratio between density of a solution (In this case, saturated solution of potassium iodide, KI) and the density of water. Assuming density of water is 1:
Specific gravity = Density
The density is the ratio between the mass of the solution and its volume.
In 100mL of water, the mass of KI that can be dissolved is:
100mL * (1g KI / 0.7mL) = 143g of KI
That means all the 100g of KI are dissolved (Mass solute)
As the volume of water is 100mL, the mass is 100g (Mass solvent)
The mass of the solution is 100g + 100g = 200g
In a volume of 100mL, the density of the solution is:
200g / 100mL = 2g/mL.
The specific gravity has no units, that means specific gravity of the saturated solution is 2
A sample of Kr gas is observed to effuse through a pourous barrier in 8.15 minutes. Under the same conditions, the same number of moles of an unknown gas requires 4.53 minutes to effuse through the same barrier. The molar mass of the unknown gas is ____________ g/mol.
Answer:
25.88 g/mol
Explanation:
Graham's law is a famous law which states that the diffusion rate or the effusion rate of any gas varies inversely to the square root of the molecular weight the gas.
So from Graham's law, we have,
[tex]$\frac{\text{time}}{M^{1/2}}=\text{constant}$[/tex]
Using the sample of Kr gas having M = 83.8
[tex]$\frac{8.15}{(83.8)^{0.5}}= \frac{4.53}{M^{0.5}}$[/tex]
[tex]$M^{0.5}= 5.088$[/tex]
M = 25.88 g/mol
Complete the sentences by identifying the correct missing words. Alph and beta particles originate from the Choose... . Protection from radiation is necessary because if radiation passes through the body it can damage Choose... . Exposure to radiation can be limited by increasing the Choose... from the radioactive source.
Answer:
Alpha and beta particles originate from the nucleus, protection from radiation is important because if the radiation passes through the body it can damage cells. Exposure to radiation is often limited by increasing the distance from the radioactive source.
Explanation:
Alpha and beta particles come from unstable atoms during their decay. This radiation is extremely harmful which may damage DNA, causing a high rate of mutation. If we increase the distance of the source of radioactive exposure we will prevent damage.Write the complete ground-state electron configuration of I⁻.
Explanation:
here's the answer to your question
Iodine's neutral atom has the following electronic configuration: 1 s² 2 s² 2 p⁶ 3 s² 3 p⁶ 4 s² 3 d¹⁰ 4 p⁶ 5 s² 4 d¹⁰ 5 p⁵. The complete ground-state electron configuration of I⁻ is [Kr]5s² 4d¹⁰ 5p⁶.
What is electronic configuration?Electronic configuration is defined as each electron moves individually within an orbital while being surrounded by an average field produced by all other orbitals. The electron configuration is used to describe an atom's ground state orbitals, but it may also be used to depict an atom that has ionized into a cation or anion by making up for any lost or gained electrons in the orbitals after it.
The ground state electronic configuration is defined as the configuration of lower energy electrons surrounding an atom's nucleus. Ground state is defined as the least energetic state feasible for a physical system. It is important because permits us to determine the location of the excited electrons' departure and return when they release a photon.
Thus, iodine's neutral atom has the following electronic configuration: 1 s² 2 s² 2 p⁶ 3 s² 3 p⁶ 4 s² 3 d¹⁰ 4 p⁶ 5 s² 4 d¹⁰ 5 p⁵. The complete ground-state electron configuration of I⁻ is [Kr]5s² 4d¹⁰ 5p⁶.
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Define pressure. Group of answer choices force exerted by solids to the surrounding area force used to compress a gas force used to melt a solid force exerted per unit area by gas particles as they strike the surfaces around them force applied to a gas to condense it
Answer:
force exerted per unit area by gas particles as they strike the surfaces around them
Explanation:
According to the kinetic molecular theory, a gas is composed of molecules. The molecules of a gas are in constant random motion and collide frequently with each other as well as with the walls of the container.
Pressure is defined as force per unit area. The pressure of a gas is the force exerted per unit area by gas particles as they strike the surfaces around them hence the answer above.
describe briefly the laboratory preparation of methane gas
Answer:
In the laboratory, methane is formed by heating sodium ethanoate with a mixture of sodium hydroxide and calcium oxide, called soda lime, on heating in the presence of a catalyst, calcium oxide, the -COONa group from sodium ethanoate is replaced by the hydrogen atom from sodium hydroxide, forming methane and sodium
Explanation:
most naturally occurring oxygen is
The reaction A + B <-------> C + D has been studied at five widely different temperature and the equilibrium tabulated.
Equilibrium constant K (at varies temperatures)
K at T1 1 x 10^-2
K at T2 2.25
K at T3 1.0
K at T4 81
K at T5 4 x 10^1
Which temperature is the products favored?
If K is greater than 1, then products are favored
Suppose that you add 24.3 g of an unknown molecular compound to 0.250 kg of benzene, which has a K f of 5.12 oC/m. With the added solute, you find that there is a freezing point depression of 3.14 oC compared to pure benzene. What is the molar mass (in g/mol) of the unknown compound
Solution :
We know that :
[tex]$\Delta T_f = k_f.m$[/tex] and [tex]$m=\frac{w_2}{m_2 \times w_1}$[/tex]
Then, [tex]$\Delta T_f = k_f.\frac{w_2}{m_2.w_1}$[/tex] ..................(1)
Where,
[tex]w_1[/tex] = amount of solvent (in kg)
[tex]w_2[/tex] = amount of solute (in kg)
[tex]m_2[/tex] = molar mass of solute (g/mole)
[tex]m[/tex] = molality of solution (mole/kg)
Given :
[tex]\Delta T_f[/tex] = [tex]3.14\ ^\circ C[/tex], [tex]k_f= 5.12\ ^\circ C/m[/tex]
[tex]=5.12 \ ^\circ C/mole/kg[/tex]
[tex]=5.12 \ ^\circ C \ kg/mole[/tex]
[tex]w_1[/tex] = 0.250 kg, [tex]w_2[/tex] = 24.3 g
Then putting this values in the equation is (1),
[tex]$3.14 = \frac{5.12 \times 24.3}{m_2 \times 0.250}$[/tex]
[tex]$m_2 = \frac{5.12 \times 24.3}{3.14 \times 0.250}$[/tex]
[tex]m_2= 158.49[/tex] g/mole
So, the molar mass of the unknown compound is 158.49 g/mole.
8. Build a neutral lithium atom.
Now, what must you do to make the lithium atom's charge change to +1?
Hint: Lithium is atomic number 3.
Add 2 electrons
Remove 1 electron
Add 1 electron
Add 1 proton
Answer:
Remove 1 electron
Explanation:
In the atom of each element, there are three subatomic particles viz: proton, neutron and electron. The number of proton (positively charged) and electron (negatively charged) determines the charge of that element. The more the proton, the more positively charged an ion is and vice versa for electron.
According to this question, a neutral atom of lithium (Li) with atomic no. 3 is given i.e. a lithium atom with charge 0. To make the lithium atom's charge change to +1, ONE ELECTRON MUST BE REMOVED OR LOST.
Note that, the proton number (atomic number) of an element does not change, rather the electron number changes in relation to the no. of protons.
The structure of the compound CuI is best described as a cubic closest packed array of iodide ions with the copper ions in tetrahedral holes. What percent of the tetrahedral holes are occupied in this solid
Answer:
12.5 %
Explanation:
In CCP, the effective number of anion is 4
That is there are 4 I- present in 1 unit cell
Number of tetrahedral void = 2*effective number of anion
= 2*4
= 8
In ZrI4, for every 4 anion, there are only 1 Zr atom.
So, one tetrahedral void is occupied per unit cell out of 8
% tetrahedral void occupied = 1*100/8
= 12.5 %
Answer: 12.5 %
Write chemical equations and corresponding equilibrium expressions for each of the two ionization steps of carbonic acid. Part A Write chemical equations for first ionization step of carbonic acid. Express your answer as a chemical equation. Identify all of the phases in your answer.
Solution :
[tex]H_2CO_3[/tex] is considered a diprotic acid.
Sp it can dissociate in solution by giving two protons.
Chemical equations for the first step of carbonic acid is :
First ionization
[tex]$H_2CO_3(aq) + H_0(1) \rightleftharpoons H_.O^+(aq) + HCO_3^-(aq)$[/tex]
Equilibrium constant expression is
[tex]$K_{a}_{1}=\frac{[H_3O^+][HCO_3^-]}{[H_2CO_3]}$[/tex]
Second ionization -
[tex]$HCO_3^-(aq) + H_2O(l) \rightleftharpoons H_3O^+(aq) + CO_3^{2-}(aq)$[/tex]
Equilibrium constant expression is
[tex]$K_{a2}=\frac{[H_3O^+][CO_3^{2-}]}{[HCO_3^-]}$[/tex]
12 grams of carbon is burnt with a certain amount of air containing 36 grams of oxygen. The product contains 24 grams of Co, and 4 grams of CO. Calculate the percentage of excess oxygen.
Answer:
C
Oxygen gas is limiting.
C(s) + O
2
→CO
2
(g)
No. of moles of carbon =
12
36
=3 moles
No. of moles of oxygen =
32
32
=1 moles
So, 2 moles of carbon is left and oxygen will be completed.
So, O
2
is limiting reagent.
Answer:
14.5
Explanation:
not sure how I got it but I hope this helped!
Which are the following exothermic or endothermic
Absorbs Energy
-Hrxn
+Hrxn
Feels Hot
Heat flows from surrounds to Reaction
Not Energetically Favorable
Energetically Favorable
Releases Energy
Feels Cold
Heat flows from the reaction to the surrounds
Answer:
Explanation:
Your mom
Which of the following statements is correct concerning the class of reactions to be expected for benzene and cyclooctatetraene?
A) Both substances undergo addition reactions.
B) Both substances undergo substitution reactions.
C) Benzene undergoes addition; cyclooctatetraene undergoes substitution.
D) Benzene undergoes substitution; cyclooctatetraene undergoes addition.
Answer:
Both substances undergo substitution reactions.
Explanation:
Let us go back to the idea of aromaticity. Aromatic substances are said to possess (4n + 2) π electrons according to Huckel rule.
Aromatic substances are unusually stable and the aromatic ring can not be destroyed by addition reactions.
Since both benzene and cyclooctatetraene are both aromatic, they do not undergo addition reactions whereby the aromatic ring is destroyed. They both undergo substitution reaction in which the aromatic ring is maintained.
draw styrene
draw the structure of cyrene
Question 6 of 30
What is the balanced equation for the redox reaction between silver and nitric
acid (HNO3) that forms nitrogen dioxide and silver ions?
A. Ag + 2H+ + NO3
-
NO2 + Ag+ + H20
0
B. Ag + 2NO3 → 2NO2 + Ag+ + O2
C. Ag + 2H+ HNO3 → NO2 + Ag+ H2O + 2e
D. Ag + NO3
NO2 + Agt + e
Answer:
its letter c
Explanation:
I hope this help
The reaction of silver and nitric acid is given with the chemical equation as Ag + 2 H⁺ + HNO₃ → NO₂ + Ag⁺ + H₂O + 2e⁻. Thus, option C is correct.
What is a redox reaction?Redox reaction can be given as the chemical reaction in which one of the reactants is oxidized and the other gets reduced. Oxidation is defined as the loss of electrons and gain of hydrogen, while reduction is defined as the gain of electrons and loss of hydrogen.
The change in the oxidation and reduction changes the oxidation states of the elements, and thereby mediated the formation of a more stable chemical compound.
The reaction of silver with nitric acid forms the release of hydrogen from nitric acid, thereby the compound gets reduced, while with the loss of electrons, the silver gets oxidized.
The chemical equation for the same can be given as:
Ag + 2 H⁺ + HNO₃ → NO₂ + Ag⁺ + H₂O + 2e⁻
Thus, option C is correct.
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A buffer is a solution that is a mixture of either a weak acid and its conjugate base or a weak base and its conjugate acid. When strong acids or strong bases are added, buffers either accept protons when they are in excess or donate protons when they have been depleted to minimize changes in pH. Which of the statements correctly describe the properties of a buffer?
a. The conjugate base of an acidic buffer will accept hydrogen protons when a strong acid is added to the solution.
b. An acidic buffer solution is a mixture of a weak acid and its conjugate base.
c. An acidic buffer solution is a mixture of a weak base and its conjugate acid.
d. The weak acid of an acidic buffer will accept hydrogen protons when a strong base is added to the solution.
e. The weak acid of an acidic buffer will donate hydrogen protons when a strong base is added to the solution.
f. The conjugate base of an acidic buffer will donate hydrogen protons when a strong acid is added to the solution.
Answer:
a. The conjugate base of an acidic buffer will accept hydrogen protons when a strong acid is added to the solution.
b. An acidic buffer solution is a mixture of a weak acid and its conjugate base.
e. The weak acid of an acidic buffer will donate hydrogen protons when a strong base is added to the solution.
Explanation:
Which of the statements correctly describe the properties of a buffer?
a. The conjugate base of an acidic buffer will accept hydrogen protons when a strong acid is added to the solution. TRUE. The conjugate base neutralizes the excess of hydrogen protons.
b. An acidic buffer solution is a mixture of a weak acid and its conjugate base. TRUE.
c. An acidic buffer solution is a mixture of a weak base and its conjugate acid. FALSE. This is a basic buffer solution.
d. The weak acid of an acidic buffer will accept hydrogen protons when a strong base is added to the solution. FALSE. The weak acid will react with the hydroxyl ions from the added base.
e. The weak acid of an acidic buffer will donate hydrogen protons when a strong base is added to the solution. TRUE. These hydrogen protons will form water.
f. The conjugate base of an acidic buffer will donate hydrogen protons when a strong acid is added to the solution. FALSE. It will accept hydrogen protons.
Why does nitrogen not show allotropy?
Answer:
Nitrogen does not show allotropy because of its small size and high electronegativity. The single N-N bond is weaker than P-P bond because of high inter electronic repulsions among non-bonding electrons due to the small bond distance. Hence it does not show allotropy.
Answer:
The nitrogen atom has short inter-bond distance, hence highly electronegative in terms of magnitude. This creates no relation in energy varieties hence no allotropes formed.
Nitrogen atom is also very small.
The standard free energy that is required for the sodium-potassium ATPase to pump two K ions into the cell and three Na ions is 43.8 kJ/mol but the standard free energy change of hydrolysis of ATP is only -32 kJ/mol. This apparent imbalance of free energy can be accounted for because ________.
Answer:
Explanation:
This apparent disparity of the free energy can be taken into account because:
the free energy produced by the hydrolysis of one ATP is adequate enough under psychological circumstances.
The Na-K ATPase aids the pumping of Na+ ions out of the cell and K+ ions into the cell. These actions occurring against their potential(concentration) gradients, which may be produced by hydrolyzing one ATP molecule.
Which of the following statements is/are correct? 1. There are 5 orbitals in
the d subshell. 2. The d orbitals can accommodate 14 electrons. 3. The first
shell contains s and p orbitals. 4. The s orbital can accommodate 2 electrons.
A. 1 and 4
B. 2 and 3
C. 3 and 4
D. 2 and 4
What volume of each solution contains 0.14 mol of KCl? Express your answer using two significant figures.
1.8 M KCl
Answer:
Solution given:
1 mole of KCl[tex]\rightarrow [/tex]22.4l
1 mole of KCl[tex]\rightarrow [/tex]74.55g
we have
0.14 mole of KCl[tex]\rightarrow [/tex]74.55*0.14=10.347g
74.55g of KCl[tex]\rightarrow [/tex]22.4l
10.347 g of KCl[tex]\rightarrow [/tex]22.4/74.55*10.347=3.11litre
volume of each solution contains 0.14 mol of KCl contain 3.11litre.
[tex]\:[/tex]
1 mole of KCl → 22.4l
1 mole of KCl → 74.55g
we have
0.14 mole of KCl → 74.55*0.14=10.347g
74.55g of KCl → 22.4l
10.347 g of KCl → 22.4/74.55*10.347=3.11litre
volume of each solution contains 0.14 mol of KCl contain 3.11litre.
Why U.S. genetically modified ingredients ruin the taste
Answer:
I hope this helps!
Explanation:
The biggest threat caused by GM foods is that they can have harmful effects on the human body. It is believed that consumption of these genetically engineered foods can cause the development of diseases which are immune to antibiotics. ... As the health effects are unknown, many people prefer to stay away from these foods.
