Answer:
The most abundant isotope is ⁴⁰Ca and the least abundant is ⁴⁶Ca
Explanation:
The mass, in percentage, of eah isotope of Calcium is their fractional composition multiplied by 100:
40Ca-0.96941*100 = 96.941% of ⁴⁰Ca
42Ca-0.00647*100 = 0.647% of ⁴²Ca
43Ca-0.0013*100 = 0.13% of ⁴³Ca
44Ca-0.02086*100 = 2.086% ⁴⁴Ca
46Ca-0.00004*100 = 0.004% ⁴⁶Ca
48Ca-0.00187*100 = 0.187% of ⁴⁸Ca
That means the most abundant isotope is ⁴⁰Ca and the least abundant is ⁴⁶Ca
A pressure cooker contains 5.68 L of air at a temperature of 390 4K if the absolute pressure of the air in the pressure cooker is 205 Pa how many moles of air are in the cooker
Answer:
3.59x10⁻⁴ mol
Explanation:
Assuming ideal behaviour we can solve this problem by using the PV=nRT formula, where:
P = 205 PaV = 5.68 Ln = ?R = 8314.46 Pa·L·mol⁻¹·K⁻¹T = 390.4 KWe input the data given by the problem:
205 Pa * 5.68 L = n * 8314.46 Pa·L·mol⁻¹·K⁻¹ * 390.4 KAnd solve for n:
n = 3.59x10⁻⁴ molAtoms are found to move from one lattice position to another at the rate of 300,000 jumps/s at 500 0C when the activation energy for their movement is 10,000 cal/mol. Calculate the jump rate at 400 0C.
Answer:
1
Explanation:
1
Define pure substance. How is it classified on the basid of chemical properties?
Answer:
if it is pure, the substances is either an element or a compound. if a substance is not chemically pure, it is either a heterogeneous mixture or a homogeneous mixture. if its composition is uniform throughout, it is a homogeneous.
20ml of water is mixed with 40gm of fine powder. Calculate the concentration of the solution obtained.
Answer:
[tex]\%m=66.7\%[/tex]
Explanation:
Hello there!
In this case, according to the given information, it turns out possible for us to calculate the concentration of the solution obtained, by knowing 20 mL of water are the same to 20 g and therefore the mass of the solution is 40g+20g=60g.
Next, we apply the following equation to obtain the required concentration:
[tex]\%m=\frac{40g}{60g} *100\%\\\\\%m=66.7\%[/tex]
Regards!
At a fixed volume, a four-fold increase in the temperature of a gas will lead to _______ in pressure.
Question 2 options:
A)
no change
B)
a two-fold decrease
C)
a four-fold decrease
D)
a four-fold increase
Answer:
D) a four-fold increase
Explanation:
According to Gay-Lussac's law, which states that the pressure of a given amount of gas is directly proportional to the temperature at a constant volume, the pressure increases with an increase in temperature.
According to this question, at a fixed volume, a four-fold increase in the temperature of a gas will lead to a four-fold increase in the pressure as well.
Of the below gases, which would deviate most from ideal gas behavior? CO O2 NH3 SF4
Answer:
For gases such as hydrogen, oxygen, nitrogen, helium, or neon, deviations from the ideal gas law are less than 0.1 percent at room temperature and atmospheric pressure. Other gases, such as carbon dioxide or ammonia, have stronger intermolecular forces and consequently greater deviation from ideality.
Explanation:
1) 7.269 moles of oxygen gas are used in combusting butane (C H..). How many moles of carbon dioxide
gas are produced? You must start with a balanced chemical equation. Start with a balanced equation
Explanation:
C4H10 + 13/2O2 ---------> 4CO2 + 5H2O
so u can work out the amount of moles by doing
moles=mass/mr
mr of C4H10 is 12 × 4 + 10 =58
=7.269/58
= 0.125moles
Then u can use the molar ratio which is
6.5:4
0.125 ÷6.5 × 4 = 0.0769moles
hope this helps:)
In the presence of excess iodide ions, the iodine formed by reaction of iodide with NBS will react further to form triiodide ions. What does the triiodide combine with to form the blue color of the endpoint
Answer:
Starch.
Explanation:
When the triiodide combine with starch, it forms dark blue colour. Amylose in starch is responsible for the occurrence of a deep blue color when the iodine is combine with the starch. The iodine molecule goes inside of the amylose coil which makes a linear triiodide ion complex that goes into the coil of the starch that leads to an intense blue-black color in the end so we can say that starch turns the colour into blue.
If 4.00 moles of O2 occupies a volume of 5.0 L at a particular temperature and pressure, what volume will 3.00 moles of oxygen gas occupy under the same condition?
Answer: Volume occupied by 3.00 moles of oxygen gas under the same condition is 3.75 L.
Explanation:
Given: [tex]n_{1}[/tex] = 4.00 moles, [tex]V_{1}[/tex] = 5.0 L
[tex]n_{2}[/tex] = 3.00 moles, [tex]V_{2}[/tex] = ?
Formula used is as follows.
[tex]\frac{V_{1}}{n_{1}} = \frac{V_{2}}{n_{2}}[/tex]
Substitute the values into above formula as follows.
[tex]\frac{V_{1}}{n_{1}} = \frac{V_{2}}{n_{2}}\\\frac{5.0 L}{4.00 mol} = \frac{V_{2}}{3.00 mol}\\V_{2} = 3.75 L[/tex]
Thus, we can conclude that volume occupied by 3.00 moles of oxygen gas under the same condition is 3.75 L.
a polluted lake is 0.300 μg (micrograms) per liter of water, what is the total mass of mercury in the lake, in kilograms, if the lake has a surface area of 15.0 square miles and an average depth of 27.0 feet?
Answer:
95.9 kg
Explanation:
First we convert 15.0 mi² to m²:
15.0 mi² * ([tex]\frac{1609.34 m}{1mi}[/tex])² = 3.88x10⁷ m²Then we convert 27.0 ft to m:
27.0 ft * [tex]\frac{0.3048m}{1ft}[/tex] = 8.23 mNow we calculate the total volume of the lake:
3.88x10⁷ m² * 8.23 m = 3.20x10⁸ m³Converting 3.20x10⁸ m³ to L:
3.20x10⁸ m³ * [tex]\frac{1000L}{1m^3}[/tex] = 3.20x10¹¹ LNow we calculate the total mass of mercury in the lake, using the given concentration:
0.300 μg / L * 3.20x10¹¹ L = 9.59x10¹⁰ μgFinally we convert μg to kg:
9.59x10¹⁰ μg * [tex]\frac{1kg}{1x10^9ug}[/tex] = 95.9 kgThis reaction was at equilibrium when 0.2 atm of iodine gas was pumped into the container, what happened to the equilibrium and the partial pressures of the gases
Answer:
Q was < K. Partial pressure of hydrogen decreased, iodine increased
Explanation:
After iodine was added the Q was [Select] K so the reaction shifted toward the Products [Select] ,The partial pressure of hydrogen [Select], Iodine [Select] |,and hydrogen iodide Decreased
Based on the equilibrium:
H2(g) + I2(g) ⇄ 2HI(g)
K of equilibrium is:
K = [HI]² / [H2] [I2]
Where [] are concentrations at equilibrium
And Q is:
Q = [HI]² / [H2] [I2]
Where [] are actual concentrations of the reactants.
When the reaction is in equilibrium, K=Q.
But as [I2] is increased, Q decreases and Q was < K
The only concentration that increases is [I2], doing partial pressure of hydrogen decreased, iodine increased
The information below describes a redox reaction.
Ag+ (aq) + Al(s) — Ag(s) + Al3+ (aq)
Ag+ (aq) + -> Ag(s)
Al(s)->A3+ (aq) + 3e-
What is the coefficient of silver in the final, balanced equation for this reaction?
Answer:
Al°(s) + 3Ag⁺(aq) => Al⁺³(aq) + 3Ag(s)
Explanation:
Oxidation: Al°(s) => Al⁺³(aq) + 3e⁻
Reduction: 3Ag⁺(aq) + 3e⁻ => 3Ag°(s)
_________________________________________
Net Rxn: Al°(s) + 3Ag⁺(aq) => Al⁺³(aq) + 3Ag(s)
One mole of neutral aluminum atoms (Al°(s)) undergo oxidation delivering 3 moles of electrons to 3 moles silver ions (3Ag⁺³(aq)) that are reduced to 3 moles of neutral silver atoms (3Ag°(s)) in basic standard state 25°C; 1atm.
A balanced equation obeys the law of conservation of mass. According to the law of conservation of mass, mass can neither be created nor be destroyed. The coefficient of silver is 3.
What is a balanced equation?A balanced chemical equation can be defined as the chemical equation in which the number of reactants and products on both sides of the equation are equal. The amount of reactants and products on both sides of the equation will be equal in a balanced chemical equation.
The numbers which are used to balance the chemical equation are called the coefficients. The coefficients are the numbers which are added in front of the formula.
The balanced chemical equation for the given redox reaction is given as:
Al (s) + 3 Ag⁺ (aq) → Al³⁺ (aq) + 3Ag (s)
Thus the coefficient of silver is 3.
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4) The initial rate of the reaction between substances P and Q was measured in a series of
experiments and the following rate equation was deduced.
rate = k[P]?[Q]
Complete the table of data below for the reaction between P and Q
*Help asap please*
Answer:
The initial rate of the reaction between substances P and Q was measured in a series of
experiments and the following rate equation was deduced.
[tex]rate = k[P]^{2} [Q][/tex]
Complete the table of data below for the reaction between P and Q
Explanation:
Given rate of the reaction is:
[tex]rate= k[P]^{2} [Q]\\=>[Q]=\frac{rate}{k.[P]^{2} } \\and \\\\\\\ [P]=\sqrt{\frac{rate}{k.[Q]} }[/tex]
Substitute the given values in this formulae to get the [P], [Q] and rate values.
From the first row,
the value of k can be calulated:
[tex]k=\frac{rate}{[P]^{2}[Q] } \\ =\frac{4.8*10^-3}{(0.2)^{2} 2. (0.30)} \\ =0.4[/tex]
Second row:
2. Rate value:
[tex]rate =0.4* (0.10)^{2} * (0.10)\\\\ =4.0*10^-3mol.dm^-3.s^-1[/tex]
3.Third row:
[tex][Q]=\frac{rate}{k.[P]^{2} } \\ =9.6*10^-3 / (0.4 *(0.40)^{2} \\ =0.15mol.dm^{-3}[/tex]
4. Fourth row:
[tex][P]=\sqrt{\frac{rate}{k.[Q]} }\\=>[P]=\sqrt{\frac{19.2*10^-3}{0.60*0.4} } \\=>[P]=0.283mol.dm^{-3}[/tex]
In the reaction below, what is the limiting reactant when 1.24 moles NH3 of reacts with 1.79 moles of NO?
4NH_3 + 6NO (right arrow) 5N_2 + 6H_2O
1. NO
2. H_2O
3. NH_3
4. N_2
Answer:
Option 1. NO
Explanation:
The balanced equation for the reaction is given below below:
4NH₃ + 6NO —> 5N₂ + 6H₂O
From the balanced equation above,
4 moles of NH₃ reacted with 6 moles of NO.
Finally, we shall determine the limiting reactant. This can be obtained as follow:
From the balanced equation above,
4 moles of NH₃ reacted with 6 moles of NO.
Therefore, 1.24 moles of NH₃ will react with = (1.24 × 6)/4 = 1.86 moles of NO
From the calculation made above, we can see that a higher amount of NO (i.e 1.86 moles) than what was given (i.e 1.79 moles) is needed to react completely with 1.24 moles of NH₃.
Therefore, NO is the limiting reactant and NH₃ is the excess reactant.
Thus, the 1st option gives the correct answer to the question
Answer:
1. NO .
Explanation:
Hello there!
In this case, according to the given information, it turns out possible for us to identify the limiting reactant by simply calculating the moles of any product, say N2, via the moles of each reactant and including the corresponding mole ratio (4:5 and 6:5):
[tex]1.24molNH_3*\frac{5molN_2}{4molNH_3}=1.55molN_2 \\\\1.79molNO*\frac{5molN_2}{6molNO}=1.50molN_2[/tex]
Thus, since NO yields the fewest moles of N2 product, we infer it is the limiting reactant.
Regards!
You dissolve 14 g of Mg(NO3)2 in water and dilute to
750 mL. What is the molarity of this solution?
Answer:
0.127M
Explanation:
Molarity of a solution = number of moles (n) ÷ volume (V)
Molar mass of Mg(NO3)2 = 24 + (14 + 16(3)}2
= 24 + {14 + 48}2
= 24 + 124
= 148g/mol
Using the formula, mole = mass/molar mass, to convert mass of Mg(NO3)2 to mole
mole = 14g ÷ 148g/mol
mole = 0.095mol
Volume = 750mL = 750/1000 = 0.75L
Molarity = 0.095mol ÷ 0.75L
Molarity = 0.127M
Acetylide ions react with aldehydes and ketones to give alcohol addition products.
a. True
b. False
Answer:
a
Explanation:
La función de la levadura en quimica
Explanation:
las levaduras son pequeños organismos unicelulares que se alimentan de azúcares simples y los descomponen en dióxido de carbono, alcohol (etanol, específicamente), moléculas de sabor y energía. El proceso se conoce como fermentación.
a) If we have a 4.5 L container of CH 10 gas at a temperature of 178 K and a pressure of 0.50 atm, then how many moles of CaHio do
we have?
b) How many grams of C4H1o do we have?
Answer:
a) 0.15 mol.
b) 8.95 g.
Explanation:
Hello there!
In this case, according to the given information, it is possible for us to infer this problem is solved by using the ideal gas equation:
[tex]PV=nRT[/tex]
And proceed as follows:
a) Here, we solve for the moles, n, as follows:
[tex]n=\frac{PV}{RT} \\\\n=\frac{0.50atm*4.5L}{0.08206\frac{atm*L}{mol*K}*178K} \\\\n=0.15mol[/tex]
b) for the calculation of the mass, we recall the molar mass of butane, 58.12 g/mol, to obtain:
[tex]0.15mol*\frac{58.12g}{1mol} =8.95g[/tex]
Regards!
which of the following illustrates a reversible change a cooking corn be rusting c frying egg and the boiling water
38. Consider the following equilibrium:
2CO(g) + O2(g) =2CO2
Keg=4.0 x 10-10
What is the value of Key for 2CO2(g) + 2COR + O2g) ?
Answer:
[tex]Key=2.5x10^{-9}[/tex]
Explanation:
Hello there!
In this case, according to the given information, it turns out possible for us to calculate the equilibrium constant value for the reverse reaction:
[tex]2CO_2(g) \rightleftharpoons 2CO(g) + O_2(g)[/tex]
By knowing that the equilibrium expression is actually:
[tex]Key =\frac{[CO]^2[O_2]}{[CO_2]^2} =\frac{1}{Keg}[/tex]
Thus, we plug in and solve for the inverse of Keq to obtain Key as follows:
[tex]Key =\frac{1}{4.0x10^{-10}}\\\\Key=2.5x10^{-9}[/tex]
Regards!
If we have 1.23 mol of NaOH in solution and 0.85 mol of Cl2 gas is available to react, which one is the limiting reactant? Give your reason.
Answer:
NaOH is the limiting reactant.
Explanation:
Hello there!
In this case, since the reaction taking place between sodium hydroxide and chlorine has is:
[tex]NaOH+Cl_2\rightarrow NaCl+NaClO+H_2O[/tex]
Which must be balanced according to the law of conservation of mass:
[tex]2NaOH+Cl_2\rightarrow NaCl+NaClO+H_2O[/tex]
Whereas there is a 2:1 mole ratio of NaOH to Cl2, which means that the moles of the former that are consumed by 0.85 moles of the latter are:
[tex]n_{NaOH}=0.85molCl_2*\frac{2molNaOH}{1molCl_2}\\\\n_{ NaOH}=1.7molNaOH[/tex]
Therefore, since we just have 1.23 moles out of 1.70 moles of NaOH, we infer this is the limiting reactant.
Regards!
Phosphine, PH3, a reactive and poisonous compound, reacts with oxygen as follows: 4PH3(g) 8O2(g) - P4O10(s) 6H2O(g) If you need to make 6.5 moles of P4O10, how many moles of PH3 is required for the reaction
Answer: 26 moles of [tex]PH_3[/tex] are required for the reaction.
Explanation:
We are given:
Moles of [tex]P_4O_{10}[/tex] = 6.5 moles
The given chemical reaction follows:
[tex]4PH_3(g)+8O_2(g)\rightarrow P_4O_{10}(s)+6H_2O(g)[/tex]
By the stoichiometry of the reaction:
If 1 mole of [tex]P_4O_{10}[/tex] is produced by 4 moles of [tex]PH_3[/tex]
So, 6.5 moles of [tex]P_4O_{10}[/tex] will be produced by = [tex]\frac{4}{1}\times 6.5=26mol[/tex] of [tex]PH_3[/tex]
Hence, 26 moles of [tex]PH_3[/tex] are required for the reaction.
Classify each phrase according to whether it applies to photophosphorylation, oxidative phosphorylation, or both
Photophosphorylation Oxidative phosphorylation Both
1. occurs in plants produces ATP
2. occurs in chloroplasts
3. occurs in mitochondria
4. involves a larger electrical component
5. involves a smaller electrical component
6. involves a proton gradient
Answer:
1. Both
2. Phosphorylation
3. Both
4. Phosphorylation
5. Oxidative.
6. Both
Explanation:
Phosphorylation only occurs in chloroplast and it involves larger electrical component. Both Phosphorylation and oxidative occurs in mitochondria and it involves proton gradient. They occur in plants to produce ATP. Oxidative involves in smaller electrical component.
Photophosphorylation is a process that captures the solar energy from the sun to transform it into chemical energy. It occurs in the chloroplast of a plant cell.
What are photophosphorylation and oxidative phosphorylation?Photophosphorylation is a process of converting solar energy from the sun to ATP needed by plants and other organisms for cellular function and activity. This process takes place in the chloroplast of the plant cell and requires electrical components.
Oxidative Phosphorylation is the process of producing ATP with the help of oxygen and enzymes hence, occurs in aerobic cells. It does not need a larger electrical component.
Both phosphorylation and oxidative phosphorylation occurs in the mitochondria of plants cells and involves a proton gradient for the formation of ATP.
Therefore, oxidative phosphorylation option 5. involves a smaller electrical component, phosphorylation option 2. occurs in the chloroplast, and option 4. needs a larger electrical component.
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calculate the maximum theoretical percent recovery from the recrystallization of 1.00g of benzoic acid
Answer:
The maximum theoretical percent recovery from the recrystallization of 1.00 g of benzoic acid from 15 mL of water = 94.9%
Note: The question is incomplete. A similar but complete question is given below:
The solubility of benzoic acid in water is 6.80g per 100mL at 100 degrees C and 0.34 g per 100mL at 25 degrees C.
Calculate the maximum theoretical percent recovery from the recrystallization of 1.00 g of benzoic acid from 15 mL of water, assuming the solution is filtered at 25 degrees C.
Explanation:
Solubility of benzoic acid in water at 100 degrees C = 6.80g per 100mL
Solubility of benzoic acid in water at 25 degrees C = 0.34 g per 100mL
Mass of benzoic acid to be theoretically recovered from 100 mL of water = 6.80 g - 0.34 g = 6.46 g
At 25 degrees;
0.34 g of benzoic acid is present in 100 mL of water
x g of benzoic acid will be present in 15 mL of water
x = 0.34 × 15 / 100 = 0.051 g
Mass of benzoic acid to be theoretically recovered from 25 mL of water = 1.00 g - 0.051 g = 0.949 g
Maximum theoretical percent recovery = (mass recovered / original mass dissolved) x 100%
Maximum theoretical percent recovery = (0.949 / 1.00) × 100% = 94.9 %
Therefore, the maximum theoretical percent recovery from the recrystallization of 1.00 g of benzoic acid from 15 mL of water = 94.9%
4. Complete the following equations:
CuCl2 + Na2CO3 → 2 NaCl +............
FeSO4 + BaCl2 →
Cu(NO3)2 + CaCO3
Answer:
2NaCl + CuCO3
FeCl2 + BaSO4
CuCO3 + Ca(NO3)2
Explanation:
Presumably this is a double replacement reaction.
A+B + C+D → A+D + C+B
It seems I may be wrong so please try to work out the problem yourself to double check, keeping in mind the charges of each compound.
which type of chemical bond would be formed between two elements having electron configuration of 1s2 2s2 2p6 3s2 and 1s2 2s2 2p4
Rocks are classified as igneous, metamorphic, or sedimentary according to
Answer:
D. the minerals they contain
Hope this answer is right!!
The compound sodium hydrogen sulfate is a strong electrolyte. Write the reaction when solid sodium hydrogen sulfate is put into water:
Answer:
NaHSO₄(s) --H₂O--> Na⁺(aq) + HSO₄⁻(aq)
Explanation:
Sodium hydrogen sulfate is a strong electrolyte, that is, when dissolved in water it completely dissociates into the cation sodium and the anion hydrogen sulfate. The corresponding chemical equation is:
NaHSO₄(s) --H₂O--> Na⁺(aq) + HSO₄⁻(aq)
The table below provides data about a gas sample.
Volume
1.0 L
Pressure
303.9 kPa
Temperature
323 K
Which of the following can be determined using the data?
A the chemical composition of the gas
B. the condensation temperature of the gas
C. the distance between gas molecules in the sample
D. the number of gas molecules in the sample
Answer:
the number of gas molecules in the sample
Please help me, it’s my last try
Answer:
Group 1A: alkali metals, or lithium family.
Group 2A: alkaline earth metals, or beryllium family.
Group 7A: the manganese family.
Group 8A: the iron family.
Explanation:
Answer:
1A: Alkali Metals
2A: Alkaline Earth Metals
7A: Halogens
8A: Noble Gases
