The number of replaceable electrons in an atom is called its valency.
Examples
Monovalent - HydrogenDivalent - OxygenValency = 8 - Number of electron in last shell [When number of electrons in last shell > 4]Valency = Number of electron in last shell [When number of electrons in last shell < 4]Thanks !
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Answer:
the combining capacity if an atom is know as valency.
the property of an element that determines the number of other atimd with an aton if the element can combine.
If we increase the temperature of the reaction that occurs in plants to create sugar. What direction does the equilibrium shift....
- Products
- No change
- Reactants
- Plants are not capable of this
The reaction used to produce sugar in plants is Photosynthesis,
6CO₂ + 6H₂O + heat ⇆ C₆H₁₂O₆ + 6O₂↑
we can see that this reaction is endothermic, it absorbs heat to occur
If we were to add more heat or increase the temperature, the left side of the equilibrium will be able to react much more, which would produce more glucose (aka sugar)
Hence increasing the temperature will shift the equilibrium to the right or towards the Products
Answer:
Explanation:
The reaction that occurs in plants to create sugar can be represented by the following equation:
6 CO2 + 6 H2O ↔ C6H12O6 + 6 O2
It is called photosynthesis because the reaction requires light energy for the plant. The reaction is controlled by enzyme within the plant. An increase in temperature will increase the collisions between enzyme and reactants; shifting the equilibrium towards the products, sugar and oxygen.
What is the final volume, in L. of a balloon that was initially at 173.8 mL at 17.5°C and was then heated to 78.0*C?
Answer:
0.21 L.
Explanation:
From the question given above, the following data were obtained:
Initial temperature (T₁) = 17.5°C = 17.5°C + 273 = 290.5 K
Initial volume (V₁) = 173.8 mL
Final temperature (T₂) = 78 °C = 78 °C + 273 = 351 K
Final volume (V₂) =?
V₁/T₁ = V₂/T₂
173.8 / 290.5 = V₂ / 351
Cross multiply
290.5 × V₂ = 173.8 × 351
290.5 × V₂ = 61003.8
Divide both side by 290.5
V₂ = 61003.8 / 290.5
V₂ = 210 mL
Finally, we shall convert 210 mL to L. This can be obtained as follow:
1000 mL = 1 L
Therefore,
210 mL = 210 mL × 1 L / 1000 mL
210 mL = 0.21 L
Thus, the final volume of the balloon is 0.21 L.
Answer:
[tex]\boxed {\boxed {\sf 0.775 \ L}}[/tex]
Explanation:
1. Calculated Final VolumeWe are asked to find the final volume of a balloon given a change in temperature. We will use Charles's Law, which states the volume of a gas is directly proportional to the temperature. The formula for this law is:
[tex]\frac{V_1}{T_1}= \frac{V_2}{T_2}[/tex]
The initial volume is 173.8 milliliters and the initial temperature is 17.5 degrees Celsius.
[tex]\frac {173.8 \ mL}{17.5 \textdegree C}= \frac{V_2}{T_2}[/tex]
The balloon is heated to a final temperature of 78.0 degrees Celsius, but the volume is unknown.
[tex]\frac {173.8 \ mL}{17.5 \textdegree C}= \frac{V_2}{78.0 \textdegree C}[/tex]
We are solving for the final volume, so we must isolate the variable V₂. It is being divided by 78.0 degrees Celsius. The inverse of division is multiplication, so we multiply both sides by 78.0 °C.
[tex]78.0 \textdegree C *\frac {173.8 \ mL}{17.5 \textdegree C}= \frac{V_2}{78.0 \textdegree C} * 78.0 \textdegree C[/tex]
[tex]78.0 \textdegree C *\frac {173.8 \ mL}{17.5 \textdegree C}=V_2[/tex]
The units of degrees Celsius cancel.
[tex]78.0 *\frac {173.8 \ mL}{17.5}=V_2[/tex]
[tex]78.0 *9.931428571 \ mL= V_2[/tex]
[tex]774.6514286 \ mL =V_2[/tex]
2. Convert to LitersWe are asked to give the volume in liters, so we must convert out units. Remember that 1 liter contains 1000 milliliters.
[tex]\frac { 1 \ L}{1000 \ mL}[/tex]
[tex]774.6514286 \ mL * \frac{ 1 \ L}{1000 \ mL}[/tex]
[tex]774.6514286 * \frac{ 1 \ L}{1000}[/tex]
[tex]0.7746514286 \ L[/tex]
3. RoundThe original values of volume and temperature have 3 and 4 significant figures. We always round our answer to the least number of sig figs, which is 3. This is the thousandths place for the number we calculated. The 6 in the ten-thousandths place tells us to round the 4 up to a 5.
[tex]0.775 \ L[/tex]
The final volume is approximately 0.775 liters.
A student was given a solid containing a mixture of nitrate salts. The sample completely dissolved in water, and upon addition of dilute HCl , no precipitate formed. The pH was lowered to about 1 and H2S was bubbled through the solution. No precipitate formed. The pH was adjusted to 8 and H2S was again bubbled in. This time, a precipitate formed. Which compounds might have been present in the unknown?
a. Ca(NO3)2
b. AgNO3
c. Fe(NO3)3
d. Cr(NO3)3
e. Cu(NO3)2
f. KNO3
g. Bi(NO3)2
Answer:
Fe(NO3)3, Cr(NO3)3, Co(NO3)3
Explanation:
According to the question, no precipitate is observed when HCl was added. This means that we must rule out AgNO3.
Again, the sulphides of Cu^2+, Bi^3+ are soluble in acidic medium but according to the question, the sulphides do not precipitate at low pH hence Cu(NO3)2 and Bi(NO3)3 are both ruled out.
The sulphides of Fe^3+, Cr^3+ and Co^3+ all form precipitate in basic solution hence Fe(NO3)3, Cr(NO3)3, Co(NO3)3 may be present.
The presence of Ca(NO3)2 and KNO3 may be confirmed by flame tests.
write the balanced equation for
[B]⁴[C][D]/[A]²
Given the following reaction: 3CuCl2(aq) 2Na3PO4(aq) --> Cu3(PO4)2(s) 6NaCl(aq) MM (g/mol) 134.45 163.94 380.58 58.44 If 285 mL of 6.3 M CuCl2 is added to excess Na3PO4 solution, how much precipitate( in grams) is produced Note: Write answer to two decimal places.
Answer:
227.78g of the precipitate are produced
Explanation:
Based on the reaction, 3 moles of CuCl2 produce 1 mole of Cu3(PO4)2 (The precipitate).
To solve this question we need to find the moles of CuCl2 added. With these moles and the reactio we can find the moles of Cu3(PO4)2 and its mass as follows:
Moles CuCl2:
285mL = 0.285L * (6.3mol / L) = 1.7955 moles CuCl2
Moles Cu3(PO4)2:
1.7955 moles CuCl2 * (1mol Cu3(PO4)2 / 3mol CuCl2) = 0.5985 moles Cu3(PO4)2
Mass Cu3(PO4)2 -380.58g/mol-
0.5985 moles Cu3(PO4)2 * (380.58g/mol) =
227.78g of the precipitate are produced
Aqueous hydrochloric acid HCl will react with solid sodium hydroxide NaOH to produce aqueous sodium chloride NaCl and liquid water H2O. Suppose 20. g of hydrochloric acid is mixed with 7.56 g of sodium hydroxide. Calculate the minimum mass of hydrochloric acid that could be left over by the chemical reaction. Round your answer to 2 significant digits.
here's the answer to your question
List the following substances in order of decreasing boiling point:
CO2, Ne, CH3OH, KF
The correct order of the substances in order of decreasing boiling point is,
KF , CH30OH , CO2 , Ne
What is boiling point?Boiling point, the temperature at which the force exerted by the surroundings upon a liquid exists equaled by the pressure exerted by the vapor of the liquid; under this situation, the addition of heat affects the transformation of the liquid into its vapor without increasing the temperature.
The main difference between the boiling point and the melting point stands that the melting point is determined as the temperature at which solid and liquid phases exist in equilibrium, whereas the boiling point stands as the temperature at which the vapor pressure of a liquid stands equal to the external pressure.
Hence, The correct order of the substances in order of decreasing boiling point is,
KF , CH30OH , CO2 , Ne
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Write the symbol for every chemical element that has atomic number greater than 55 and less than 140.8 u
Two common methods to generate an aldehyde is by oxidation of an alcohol and through ozonolysis.
a. True
b. False
Answer:
a. True.
Explanation:
Only primary and secondary alcohols can oxidise to give an aldehyde. But a weak oxidizing agent must be used to prevent formation of a carboxylic acid or ketone.
weak oxidizing agents: Chromyl chloride, silver/oxygen/500°C
take an example of ethanol:
[tex]{ \bf{CH _{3} CH_{2}OH \: \: \frac{Ag/O_{2} }{500 \degree C} > \: \:CH _{3} CHO}}[/tex]
[tex]{ \sf{CH _{3} CHO \: \: is \: ethanal}} [/tex]
By ozonolysis:
Here, reactants are Ozone gas, Carbon tetrachloride at a temperature (<20°C), ethanoic acid, zinc and water.
take an example of propanol:
if it undergoes ozonolysis, it gives ethanal and methanal.
Answer:
A. True
Explanation:
Only primary and secondary alcohols can oxidise to give an aldehyde. But a weak oxidizing agent must be used to prevent formation of a carboxylic acid or ketone.
weak oxidizing agents: Chromyl chloride, silver/oxygen/500°C
take an example of ethanol:
By ozonolysis:
Here, reactants are Ozone gas, Carbon tetrachloride at a temperature (<20°C), ethanoic acid, zinc and water.
take an example of propanol:
if it undergoes ozonolysis, it gives ethanal and methanal.
Determine the number of moles of aluminum in 2.154 x 10-1 kg of Al. Group of answer choices 5816 mol 7.984 mol 6.02 X 1023 mol 4.801 mol 8.783
Answer:
Avogadro's number is 1 mol = 6.02 * 10^23 elements
It means that 1 mol of atoms is 6.02 * 10^23 atoms
1 mol of atoms = 6.02 * 10^23 atoms
From there, if you divide both sides by 1 mol of atoms, you get
1 = 6.02 * 10^23 atoms / 1 mol of atoms.
That means, that to pass from a number of moles of atoms to number of atoms you have to multipby by the conversion factor
6.02*10^23 atoms Al/ 1 mol Al
That is the second option of the list.
Explanation:
When a chemical changes from the solid phase to the gas phase, this is an example of What chemical property?
Answer:
sublimation
Explanation:
solid => liquid Melting
liquid => solid freezing
liquid => gas evaporation
gas => liquid condensation
solid => gas sublimation
gas => solid deposition (e.g.; formation of frost), however some scholars will also refer to this process as sublimation.
There are _______ alkanes with molecular formula C10H22
a. 74
b. 75
c. 76
d. 77
Which species is the conjugate base of H2SO3
Explanation:
As you know, the conjugate base of an acid is determined by looking at the compound that's left behind after the acid donates one of its acidic hydrogen atoms.
The compound to which the acid donates a proton acts as a base. The conjugate base of the acid will be the compound that reforms the acid by accepting a proton.
In this case, sulfurous acid has two protons to donate. However, the conjugate base of sulfurous acid will be the compound left behind after the first hydrogen ion is donated.
According to an informal 1992 survey, the drinking water in about one-third of the homes in Chicago had lead levels of about 10 ppb. Dr. Koether lived in Chicago from 1996 to 1998. Assuming she drank 1.4 L of water a day, calculate the total amount of lead in mg (using one decimal place) that she was exposed to over the two years if she lived in a home that had such high levels of lead.
Answer:
10.2 mg
Explanation:
Step 1: Calculate the total amount of water she drank
1 year has 365 days and she lived in Chicago for 2 years = 2 × 365 days = 730 days.
If she drank 1.4 L of water per day, the total amount of water she drank is:
730 day × 1.4 L/day = 1022 L
Step 2: Calculate the amount of Pb in 1022 L of water
The concentration of Pb is 10 ppb (10 μg/L).
1022 L × 10 μg/L = 10220 μg
Step 3: Convert 10220 μg to milligrams
We will use the conversion factor 1 mg = 1000 μg.
10220 μg × 1 mg/1000 μg = 10.2 mg
Given the following formula for calculating the ionization energy of one-electron species such as Li2+, He+, and H, calculate the ionization energy (in J/mol) for B4+. Use scientific notation in answers (ex: 1E10, 3.20E-6)
Answer:
The answer is "[tex]32819.9 \ \frac{J}{mol}\\\\[/tex]"
Explanation:
[tex]Boron: 5^{B}\to 1s^2 2s^2 2p^1[/tex]
[tex]\Delta E=-2.18\times 10^{-18}\ \frac{J}{atom}\ (\frac{1}{\infity^2}-\frac{1}{n^2_{initial}})(z^2) (6.022\times 10^{23}\ \frac{atom}{mol})\\\\[/tex]
[tex]=-2.18\times 10^{-18}\ \frac{J}{atom}\ (0-\frac{1}{1})(5^2) (6.022\times 10^{23}\ \frac{atom}{mol})\\\\ =2.18\times 10^{-18}\times 25 \times 6.022\times 10^{23}\ (\frac{J}{mol})\\\\ =328.199 \times 10^{5}\ (\frac{J}{mol})\\\\ =32819 \times 10^{3}\ (\frac{J}{mol})\\\\ =32819.9 \ (\frac{J}{mol})\\\\[/tex]
How do the particles in plasmas compare with
the particles in solids?
O Plasmas and solids are both made up of cation-anion pairs.
• Solids and plasmas are both made up of electrons and cations.
Solids are made up of cation-anion pairs, but plasmas are not.
O Plasmas are made up of cation-anion pairs, but solids are not.
Answer:
Solids are made up of cation-anion pairs, but plasmas are not
Explanation:
Solid is made from cautions and anions while the plasma is not and hence both are made from the cautions and anion plasma. Solids and plasma is made from electrons and solids are made from caution and anion pairs. Plasma is a good conductor of electricity as they have a lot of mobile charged particles.Select all that are True.
a. For an isoelectronic series, the species with the most negative charge has the smallest first ionization energy.
b. The removal of an electron from a neutral atom results in a release of energy in the form of heat.
c. For an isoelectronic series, the species with the most positive charge has the smallest first ionization energy.
When (R)-2-chloro-3-methylbutane is treated with potassium tert-butoxide, a monosubstituted alkene is obtained. When this alkene is treated with HBr, a mixture of products is obtained. Identify all of the expected products.
Answer:
See explanation and image attached
Explanation:
The reaction of (R)-2-chloro-3-methylbutane with potassium tert-butoxide yields a monosubstituted alkene .
Since the base is bulky, the Hoffman product predominates because attack occurs at the less hindered carbon atom to yield the major product as shown.
The alkene reacts with HBr at the secondary carbon atom to yield a carbocation intermediate which is flat and planar. Attack on either face of the carbocation yields a racemic mixture of the (2R) and (2S) products.
Rearrangement of the carbocation to yield a tertiary carbocation gives the 2-bromo-2-methyl butane product as shown in the image attached.
What is a reaction rate?
Answer:
A reaction is the time that is required for a chemical reaction to go essential to completion
The correct geometry around oxygen in CH3OCH3 is
(a). linear. (b). bent. C). tetrahedral/(a). trigonal planar
Explanation:
the force of the lone pairs from the bottom would cancel out the force of the lone pairs from the top. Thus, the molecule will be linear.
Do you think that the human being is the center of the universe?
A capsule containing 0.500 L of air at 1.00 atm is compressed to 3.25 atm. At that point, what is the volume of the gas in the capsule?
Answer:
V₂ = 0.154 Liters
Explanation:
Pressure => P
Volume => V
Temperature => T
mass (moles) => n
This problem...
P₁ = 1.00 ATM P₂ = 3.25 ATM
V₁ = 0.500L V₂ = ?
T₁ = constant T₂ = T₁ = constant
n₁ = constant n₂= n₁ = constant
P₁V₁/n₁T₁ = P₂V₂/n₂T₂ => V₂ = V₁(P₁/P₂) = 0.500L (1.00ATM/3.25ATM) = 0.154 Liters
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.
A 1 liter solution contains 0.370 M hypochlorous acid and 0.493 M sodium hypochlorite. Addition of 0.092 moles of barium hydroxide will: (Assume that the volume does not change upon the addition of barium hydroxide.)
In the original solution you have the mixture of a weak acid (Hypochlorous acid) and its conjugate base (Sodium hypochlorite). That is a buffer.
The barium hydroxide will react with hypochlorous acid. If this reaction cause the complete reaction of hypochlorous acid, the buffer break its capacity and the pH change in several units. In this case:
The addition of barium hydroxide will raise the pH slightly because the buffer still working.
The initial moles of those species are:
Hypochlorous acid:
[tex]1L * \frac{0.370mol}{1L} = 0.370 moles[/tex]
Sodium hypochlorite:
[tex]1L * \frac{0.493mol}{1L} = 0.493 moles[/tex]
Now, a strong acid as barium hydroxide (Ba(OH)₂) reacts with a weak acid as hypochlorous acid (HClO) as follows:
Ba(OH)₂ + 2HClO → Ba(ClO)₂ + 2H₂O
For a complete reaction of 0.092 moles of barium hydroxide are required:
[tex]0.092 moles Ba(OH)_2*\frac{2mol HClO}{1molBa(OH)_2} = 0.184 moles HClO[/tex]
As there are 0.370 moles, the moles of HClO after the reaction are:
0.370 moles - 0.184 moles = 0.186 moles of HClO will remain
As you still have hypochlorite and hypochlorous acid you still have a buffer.
Thus, the pH will raise slightly because the amount of acid is decreasing and slightly because the buffer can keep the pH.
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4. A balloon is filled with 3.0 L of helium at 310 K. The balloon is placed in an oven where the
temperature reaches 340 K. What is the new volume of the balloon?
Answer:
3,29L
Explanation:
3.29L = V2
Formula: V1/T1 = V2/T2
--------------------
Given:
V1 = 3.0 L V2 = ?
T1 = 310 K T2 = 340 K
--------------------
Plugin:
(X stands in place of V2 just to make it easier to look at)
[3.0L / 310K = X / 340K]
(3.0L / 310K = 0.01L/K)
0.01L/K = X / 340K
(multiply 340K on both sides, it cancels out on the right)
0.01L/K * 340K = X
(0.01L/K * 340K = 3.29L)
**3.29L = X**
[or]
**3.29L = V2**
A sample of an ideal gas is slowly compressed to one-half its original volume with no change in temperature. What happens to the average speed of the molecules in the sample
Answer:
See explanation
Explanation:
The average speed of the molecules of a gas depends on the temperature of the gas and its molar mass and not on the volume of the gas.
The average velocity of a gas is given by; vrms=√3RTM
R= gas constant
T= Absolute temperature
M= molar mass of the gas
Where the temperature of the gas is held constant, the average velocity of gas molecules depends on the molar mass of the gas. Hence, if a sample of gas is slowly compressed to one-half of its original volume with no change in temperature, the average speed of the molecules in the sample of gas remains the same.
How many moles of NiCl2 can be formed in the reaction of 7.00 mol of Ni and 14.0 mol of HCl?
Answer:
since the concentration of limiting reactant are the same for both nickel and hydrochloric acid, they both will produce the same amount if Nickel Chloride
7 mols of [tex]NiCl_2[/tex] formed in a reaction of 7 mol of Ni and 14 mol of HCl.
The moles of Ni = 7 mol
The mols of HCl = 14 mol
It is required to calculate moles of [tex]NiCl_2[/tex]
What is a mole?A mole corresponds to the mass of a substance that contains [tex]6.023 \times 10^{23}[/tex]particles of the substance. The mole is the SI unit for the amount of a substance. Its symbol is mol.
The reaction of Ni and HCl occurs as
[tex]Ni +2 HCl \to NiCl_2 + H_2[/tex]
Since the concentration of limiting reactant are the same for both nickel and hydrochloric acid, they both will produce the same amount of Nickel Chloride.
If we have 7 mols of Ni and 14 mols of HCl, then when the 7 moles of Ni has reacted, we will still have 7 moles of HCl unreacted.
So, the moles of [tex]NiCl_2[/tex] formed equal to the moles of Ni and HCl reacted.
Therefore, 7 mols of [tex]NiCl_2[/tex] formed in a reaction of 7 mol of Ni and 14 mol of HCl.
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Electrophilic addition reaction of conjugated dienes that occur at high temperature and/or long reaction times (reversible conditions) are said to be under kinetic control. Group of answer choices True False
Answer:
False
Explanation:
Electrophilic addition reactions may be under kinetic or thermodynamic control. Whether the reaction is under kinetic or thermodynamic control is easily deducible from the reaction time.
Shorter reaction time often reflect kinetic control while longer reaction reaction times favour thermodynamic control.
Hence, electrophilic addition reaction of conjugated dienes that occur at high temperature and/or long reaction times (reversible conditions) are said to be under thermodynamic and not kinetic control.
State the different radiations emitted by radioactive elements.
Answer:
gamma rays , alpha particles , beta particles , neutrons
10. At 573K, NO2(g) decomposes forming NO and O2. The decomposition reaction is second order in NO2 with a rate constant of 1.1 M-1s-1. If the initial concentration of NO2 is 0.056 M, how long will it take for 75% of the NO2 to decompose
Answer:
48.67 seconds
Explanation:
From;
1/[A] = kt + 1/[A]o
[A] = concentration at time t
t= time taken
k= rate constant
[A]o = initial concentration
Since [A] =[A]o - 0.75[A]o
[A] = 0.056 M - 0.042 M
[A] = 0.014 M
1/0.014 = (1.1t) + 1/0.056
71.4 - 17.86 = 1.1t
53.54 = 1.1t
t= 53.54/1.1
t= 48.67 seconds
Hence,it takes 48.67 seconds to decompose.
