The activity of a certain isotope dropped from 3200 ci to 800 ci in 24.0 years. what is the half-life of this isotope (in years)? show your work.
Consider this reaction: 2al(s) + 3 cucl2(aq) → 2alcl3(aq) + 3 cu(s) if the concentration of cucl2 drops from 1.000 m to 0.655 m in the first 30.0 s of the reaction, what is the average rate of reaction over this time interval?
The average rate of reaction for CuCl₂ is found by dividing the concentration change (0.345 M) by the time interval (30.0 s), resulting in an average reaction rate of 0.0115 M/s for both the disappearance of CuCl₂ and the formation of Cu.
The student is asking about calculating the average rate of reaction using changes in the concentration of a reactant over a given time interval. The average rate of reaction can be calculated by dividing the change in concentration of a reactant by the time period over which the change occurred. In this case, the concentration of CuCl₂ drops from 1.000 M to 0.655 M over 30.0 seconds.
To find the average rate at which CuCl₂ has reacted, we can use the formula:
Calculate the change in concentration of CuCl₂:The average rate of reaction for the disappearance of CuCl₂ is 0.0115 M/s. Since the reaction stoichiometry shows 3 moles of CuCl₂ produces 3 moles of Cu, the average rate of formation of Cu is also 0.0115 M/s.
Jessie has never seen snow, but today the weather conditions may be just right! He knows the temperature on the Fahrenheit thermometer must be _______ degrees or lower for him to see his first snow fall.
A) 32 o
B) 20 o
C) -10 0
D) -32 0
The key on a pie chart represents...
Answer:
data that adds up to 100%
Explanation:
What mass of salt (nacl) should you add to 1.80 l of water in an ice cream maker to make a solution that freezes at -13.4 ∘c ? assume complete dissociation of the nacl and density of 1.00 g/ml for water?
The volume of a gas is 450 mL when its pressure is 1.00 atm. If the temperature of the gas does not change, what is the pressure when its volume is changed to 2.00 L?
Use: P1V1=P2V2
A) 0.225 atm
B) 0.444 atm
C) 2.25 atm
D) 4.44 atm
Answer:
A) 0.225atm
Explanation:
P1V1 = P2V2
V1 = 450ml
P1 = 1.0atm
V2 = 2L = 2 X 100 = 2000ml
P2 =?
1.0 X 450 = P2 X 2000
P2 = (1.0 X 450)/2000
= 0.225atm
Find the number of moles of water that can be formed if you have 226 mol of hydrogen gas and 108 mol of oxygen gas.
Different environments cause different species to Blank Space __________.
become more diverse
become less diverse
become extinct
have similar traits
The stalk that holds the anther up so that pollination and fertilization can occur is the _______. :
stigma
style
filament
anther
the theory general relativity was discovered by who
Hydrogen is used as a rocket fuel because it is very light and reacts explosively and completely with oxygen. for the combustion reaction 2h2(g)+o2(g)⇌2h2o(g) what is the likely magnitude of the equilibrium constant k?
The reaction tends to completion hence K should be in the order of K>103.
The equilibrium constant is a number that indicates the extent to which reactants are converted to products in a chemical reaction. A high value of equilibrium constant indicates that the system contains mostly products and few reactants at equilibrium. A low equilibrium constant indicates that the concentration of reactants is greater than the concentration of products at equilibrium.
For the reaction; 2H2(g) + O2(g) ⇌ 2H2O(g), we know the reaction to be explosive and tend to completion since it is a combustion reaction. This means that the reactants are mostly converted to products and the equilibrium constant will be large. Hence K should be in the order of K>103.
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Hydrogen is used as a rocket fuel because it is very light and reacts explosively and completely with oxygen. For the combustion reaction 2H2(g)+O2(g)⇌2H2O(g) what is the likely magnitude of the equilibrium constant K?
1. K<10−3
2. 10−3
3. K=0
4. K>103
What is the number “4” in SiCl4?
Match each type of titration to its ph at the equivalence point for solutions at 25 ∘c. drag each item to the appropriate bin. view available hint(s) resethelp ph less than 7 ph equal to 7 ph greater than 7
Which of the following is an endothermic reaction?
Question 1 options:
sodium chloride dissolving in water
strong hydrochloric acid dissolving in water
a liquid changing to a gas
sugar dissolving in water
Answer: a liquid changing to a gas
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An endothermic reaction is one that absorbs heat. The dissolving of sodium chloride or sugar in water is usually endothermic since these processes typically absorb heat. The transition of a liquid to a gas is also an endothermic process as it requires heat input.
Explanation:An endothermic reaction is a process that absorbs heat from the surroundings. When sodium chloride dissolves in water, it can be an endothermic process as the solution usually gets cooler, indicating that heat is absorbed from the surroundings to break the ionic bonds and dissolve the salt. The dissolving of sugar in water generally is also considered slightly endothermic for similar reasons. A liquid changing to a gas, such as water boiling, is an endothermic process as it requires heat to overcome the intermolecular forces in the liquid. Finally, although dissolving strong hydrochloric acid in water is also an interaction with water, it is typically an exothermic process, where heat is released.
The activation energy for the reaction no2(g)+co(g)⟶no(g)+co2(g) is ea = 100 kj/mol and the change in enthalpy for the reaction is δh = -250 kj/mol . what is the activation energy for the reverse reaction?
Final answer:
The activation energy for the reverse reaction is calculated using the given activation energy for the forward reaction (100 kJ/mol) and the change in enthalpy of the reaction (-250 kJ/mol), resulting in an activation energy of 350 kJ/mol for the reverse reaction.
Explanation:
The question is about finding the activation energy for the reverse reaction based on the given activation energy and the change in enthalpy for the forward reaction. Using the provided data, Ea for the forward reaction is 100 kJ/mol and ΔH for the reaction is -250 kJ/mol.
To find the activation energy for the reverse reaction, we can use the concept that the sum of the activation energies for the forward and reverse reactions is equal to the difference in energy between the products and reactants. This relationship is derived from the potential energy diagram of a chemical reaction.
The activation energy for the reverse reaction can be calculated using the equation:
Ea(reverse) = Ea(forward) + ΔH
Substituting the given values:
Ea(reverse) = 100 kJ/mol - (-250 kJ/mol)
Ea(reverse) = 100 kJ/mol + 250 kJ/mol
Ea(reverse) = 350 kJ/mol
Therefore, the activation energy for the reverse reaction is 350 kJ/mol.
A wave with a frequency of 14 hertz has a wavelength of 3 meters. At what speed will this wave travel?
The speed of a wave can be determined by multiplying its frequency by its wavelength. In this case, a wave with a frequency of 14 hertz and a wavelength of 3 meters will travel at a speed of 42 meters per second.
Explanation:This is a question related to the physics of wave motion. The speed of a wave can be calculated using the formula:
Speed = Frequency x Wavelength
. Given the frequency of the wave is 14 hertz and the wavelength is 3 meters, you can plug these values into the formula. Therefore, the speed of the wave would be:
14 Hertz x 3 meters = 42 meters per second
. Hence, the wave will travel at a speed of 42 meters per second.
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Noble gas notation write the electron configuration for the manganese atom
Helium has a density of 1.79 x 10-4 g/mL at standard temperature and pressure. A balloon has a volume of 6.3 liters. Calculate the mass of helium that it would take to fill the balloon
Answer:
1.1 x 10-3 g
Explanation:
if 100. mL of 0.800 M Na2SO4 is added to 200. mL of 1.20 M NaCl, what is the concentration of Na+ ions in the final solution? Assume fhat the volumes are additive
The concentration of Na+ ions in the final solution is determined by calculating the total moles of Na+ in the final solution and dividing by the total volume of the solution. In this example, it is calculated to be 1.33 M.
Explanation:
The subject of the question deals with determining the concentration of sodium ions (Na+) in a mixed solution of sodium sulfate (Na₂SO₄) and sodium chloride (NaCl). The concentration of Na+ ions in the solution can be calculated using the molarity (M) relationships of the two solutions.
First, we determine the amount of Na+ contributed from each solution. The Na₂SO₄ solution will contribute 2 moles of Na+ for each mole of Na₂SO₄, and the NaCl solution will contribute 1 mole of Na+ per mole of NaCl.
In Na₂SO₄, mols = Molarity * Volume (L) = 0.800 M * 0.100 L = 0.080 moles. Each mole of Na₂SO₄ gives 2 moles of Na+, hence total moles of Na+ from Na₂SO₄ is 2 * 0.080 = 0.160 moles.
In NaCl, mols = Molarity * Volume (L) = 1.20 M * 0.200 L = 0.240 moles. Total moles of Na+ from NaCl is 0.240 moles. The total Na+ in the solution is the sum of the Na+ from each, so total moles of Na+ = 0.160 + 0.240 = 0.400 moles.
Finally, molarity of Na+ in the final solution is total moles of Na+ divided by total volume (in Liters). Since it is given that volumes are additive, total volume = 0.100 + 0.200 = 0.300 L. Therefore, molarity of Na+ (M) = 0.400 moles / 0.300 L = 1.33 M. So, the concentration of Na+ in the final solution is 1.33 M.
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Is calcium disodium ionic or covalent?
Calculate the molarity of a solution made by adding 45.4 g of nano3 to a flask and dissolving it with water to create a total volume of 2.50 l.
The molarity of [tex]{\text{NaN}}{{\text{O}}_{\text{3}}}[/tex] solution is [tex]\boxed{{\text{0}}{\text{.214 M}}}[/tex].
Further Explanation:
The proportion of substance in the mixture is called concentration. The most commonly used concentration terms are as follows:
1. Molarity (M)
2. Molality (m)
3. Mole fraction (X)
4. Parts per million (ppm)
5. Mass percent ((w/w) %)
6. Volume percent ((v/v) %)
Molarity is a concentration term that is defined as the number of moles of solute dissolved in one litre of the solution. It is denoted by M and its unit is mol/L.
The formula to calculate the molarity of the [tex]{\text{NaN}}{{\text{O}}_{\text{3}}}[/tex]solution is as follows:
[tex]{\text{Molarity of NaN}}{{\text{O}}_{\text{3}}}{\text{ solution}} = \frac{{{\text{Moles}}\;{\text{of}}\;{\text{NaN}}{{\text{O}}_{\text{3}}}}}{{{\text{Volume }}\left( {\text{L}} \right){\text{ of}}\;{\text{NaN}}{{\text{O}}_{\text{3}}}{\text{ solution}}}}[/tex] …… (1)
The formula to calculate the moles of [tex]{\text{NaN}}{{\text{O}}_{\text{3}}}[/tex]is as follows:
[tex]{\text{Moles of NaN}}{{\text{O}}_{\text{3}}} = \frac{{{\text{Given mass of NaN}}{{\text{O}}_{\text{3}}}}}{{{\text{Molar mass of NaN}}{{\text{O}}_{\text{3}}}}}[/tex] …… (2)
The given mass of [tex]{\text{NaN}}{{\text{O}}_{\text{3}}}[/tex] is 45.4 g.
The molar mass of [tex]{\text{NaN}}{{\text{O}}_{\text{3}}}[/tex]is 84.99 g/mol.
Substitute these values in equation (2).
[tex]\begin{aligned}{\text{Moles of NaN}}{{\text{O}}_3}&=\left( {{\text{45}}{\text{.4 g}}} \right)\left( {\frac{{{\text{1 mol}}}}{{{\text{84}}{\text{.99 g}}}}} \right)\\&=0.5341\;{\text{mol}}\\\end{aligned}[/tex]
Substitute 0.5341 for the moles of [tex]{\text{NaN}}{{\text{O}}_{\text{3}}}[/tex]and 2.50 L for the volume of [tex]{\text{NaN}}{{\text{O}}_{\text{3}}}[/tex] solution in equation (1).
[tex]\begin{aligned}{\text{Molarity of NaN}}{{\text{O}}_{\text{3}}}{\text{ solution}}&=\frac{{{\text{0}}{\text{.5341 mol}}}}{{{\text{2}}{\text{.50 L}}}}\\&=0.21{\text{364 M}}\\&\approx{\text{0}}{\text{.214 M}} \\ \end{aligned}[/tex]
The molarity of the [tex]{\mathbf{NaN}}{{\mathbf{O}}_{\mathbf{3}}}[/tex]solution is 0.214 M.
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Answer details:
Grade: Senior School
Subject: Chemistry
Chapter: Concentration terms
Keywords: molarity of NaNO3 solution, 2.50 L, volume of NaNO3 solution, moles of NaNO3, given mass, molar mass, 84.99 g/mol, 45.4 g, 0.214 M, NaNO3, molar mass, given mass.
Write a net ionic equation to show that acetylsalicylic acid (aspirin), hc9h7o4, behaves as a brønsted-lowry acid in water.
Explanation:
According to the Bronsted-Lowry conjugate acid-base theory:
An acid is defined as a substance which looses donates protons and thus forming conjugate base.A base is defined as a substance which accepts protons and thus forming conjugate acid.Acetylsalicylic acid when dissolved in water donates its proton to form conjugate base and water gains the proton to form conjugate acid.The net ionic equation is given as:
[tex]HC_9H_7O_4(0+H_2O\rightarrow (C_9H_7O_4)^{-}+H_3O^+[/tex]
What is the formula of sodium bicarbonate
A solution has [oh−] = 4.0×10−8. what is the value of [h+] for the solution? answers
The value of [H+] for the solution with [OH−] = 4.0×10−8 is calculated using the formula [H+] = Kw / [OH−], yielding a hydronium ion concentration of 2.5×10−7 M.
Explanation:To find the value of the hydronium ion concentration ([H+]) for a solution with a given hydroxide ion concentration ([OH−]), you can use the ion product constant for water (Kw), which is always 1.0 × 10−14 M2 at 25°C. The formula is [H+] = Kw / [OH−]. When the [OH−] is 4.0 × 10−8, we can calculate the [H+] as follows:
[H+] = 1.0 × 10−14 / 4.0 × 10−8[H+] = 2.5 × 10−7 MTherefore, the hydronium ion concentration of the solution is 2.5 × 10−7 M.
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A certain weak acid, ha, has a ka value of 3.6×10−7. part a calculate the percent ionization of ha in a 0.10 m solution. express your answer to two significant figures and include the appropriate units. view available hint(s)
Final answer:
The percent ionization of HA in a 0.10 M solution, with a Ka of 3.6×10⁻⁷, is approximately 0.19%.
Explanation:
The percent ionization of a weak acid can be calculated using its Ka value and the initial concentration of the acid. For HA, with a Ka of 3.6×10⁻⁷ and an initial concentration of 0.10 M, the percent ionization is determined as follows: First, set up the reaction as HA → H+ + A-. The equilibrium expression is Ka = [H+][A-] / [HA]. Assuming x is the amount ionized, we have Ka = x² / (0.10 - x). Solving this equation for x, we approximate that x is small compared to the initial concentration, so 0.10 - x is nearly 0.10. Therefore, Ka ≈ x² / 0.10 M. Solving for x gives x = sqrt(Ka × 0.10 M), and the percent ionization = (x / 0.10 M) × 100%. Substituting in the given values, we get percent ionization ≈ sqrt(3.6×10⁻⁷ × 0.10 M) / 0.10 M × 100% = 0.19%.
Water (h2o) and methane (ch4) have similar molar masses. methane changes from a liquid to a gas at -161oc. water becomes a gas at 100oc. what could account for this difference
If the apparent magnitude of a star increases,the star get brighter, true or false?
The solubility of silver chloride can be increased by dissolving it in a solution containing ammonia. agcl (s) ag+ (aq) + cl- (aq) k1 = 1.6 x 10-10 ag+ (aq) + 2nh3 (aq) ag(nh3)2+ (aq) k2 = 1.5 x 107 what is the value of the equilibrium constant for the overall reaction? agcl (s) + 2nh3 (aq) ag(nh3)2+ (aq) + cl- (aq) knet = ? question 14 options:
a.1.5 x 107
What is the correct formula for the compound formed between iron(iii) ion and the oxide ion?
The correct formula for the compound formed between the iron(III) ion and the oxide ion is Fe2O3.
Explanation:The compound formed between the iron(III) ion and the oxide ion is called iron(III) oxide. The formula for this compound can be determined by balancing the charges of the ions. The iron(III) ion has a charge of +3 and the oxide ion has a charge of -2. To balance the charges, we need two iron(III) ions for every three oxide ions. Therefore, the correct formula for the compound is Fe2O3.
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Given the balanced equation 3H2(g)+N2(g)=2NH3(g), calculate the mass of NH3 produced by the complete reaction of 2.55g of H2
The mass of NH3 produced from the complete reaction of 2.55g of H2 is calculated to be 14.45 g, based on the molar masses of H2 and NH3 and the stoichiometry of the given balanced chemical equation.
Explanation:To calculate the mass of NH3 produced by the complete reaction of 2.55g of H2, we first need to determine the molar mass of H2. Knowing that the atomic mass of hydrogen is 1.0, we can say that the molar mass of H2 is 2.0 g/mol. Next, we need to find out how many moles of H2 are in 2.55 g:
Number of moles of H2 = mass (g) / molar mass (g/mol) = 2.55 g / 2.0 g/mol = 1.275 mol
Using the stoichiometry of the balanced equation (N2(g) + 3H2(g) → 2NH3(g)), we can see that 3 moles of H2 produce 2 moles of NH3. Therefore, we can set up a proportion to find the number of moles of NH3 that would be produced from 1.275 moles of H2:
(1.275 mol H2) * (2 mol NH3 / 3 mol H2) = 0.85 mol NH3
Now, to find the mass of NH3, we need to know its molar mass. The atomic mass of nitrogen is 14.0 and hydrogen is 1.0, so the molar mass of NH3 is 14.0 + (3 * 1.0) = 17.0 g/mol. Finally, we can calculate the mass of NH3 produced:
Mass of NH3 = number of moles * molar mass = 0.85 mol * 17.0 g/mol = 14.45 g