To determine the amount of gold-198 remaining after 13.5 days, we can use the formula for radioactive decay:
N(t) = N₀ * (1/2)^(t / T₁/₂)
Where:
N(t) is the amount of gold-198 remaining after time t
N₀ is the initial amount of gold-198
T₁/₂ is the half-life of gold-198
t is the elapsed time
Given that the half-life of gold-198 is 2.7 days, we can substitute the values into the equation:
N(13.5) = 323.7 mg * (1/2)^(13.5 / 2.7)
N(13.5) = 323.7 mg * (1/2)^5
N(13.5) = 323.7 mg * 1/32
N(13.5) = 10.11875 mg
Therefore, approximately 10.12 mg of the gold-198 sample will remain after 13.5 days.
To explain further, after each half-life, the amount of gold-198 is reduced by half. Since 13.5 days is equivalent to 5 half-lives (13.5 / 2.7 = 5), we multiply the initial amount by (1/2)^5 to calculate the remaining amount. This yields a result of 1/32 or approximately 0.03125, which when multiplied by the initial amount of 323.7 mg, gives us 10.12 mg as the remaining quantity.
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The use of uranium-238 to determine the age of a geological formation is a beneficial use of
O 1.
nuclear fusion
2.
nuclear fission
3.
radioactive isomers
4.
radioactive isotopes
Answer:
4- radioactive isotopes
Explanation:
I don't remember exactly but this question was on the regents
Uranium-238 is a non- fissile element. It is a radioactive isotope that can be best used to determine geological formations. Thus, option 4 is correct.
What are radioactive isotopes?Radioactive isotopes are elements that have an unstable atomic nucleus and can undergo radioactive decay to produce new particles and energy. They have the same atomic number as that of their parent species.
Isobars are a substance that has atomic mass and do not include uranium. Nuclear fusion and fission are the processes of nuclear energy that combine or splits the unstable nucleus to form a new particle.
Therefore, option 4. Uranium-238 is a radioactive isotope.
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Explain Newton's 2nd Law of motion
Answer:
Newtons second law says that acceleration (gaining speed) happens when a force acts on a mass (object)
Explanation:
For example riding your bicycle, your bicycle is the mass and your leg muscles pushing on the pedals of your bicycle is the force.
does anyone wanna help me with my question for chemistry [i'll comment the question to you lol someone keeps sending links into my questions]
Answer:
same I was looking for a question like this I was asking question and someone kept commenting this bitly thing i dont kno I though it was just weird and frustrating lol
What is a chemical bond?
A set of aqueous solution s are prepared containing different acids at the same concentration: acid, and hydrobromic acid. Which solution(s) are the most electrically acetic acid, chloric conductive? (a) chloric acid (b) hydrobromic acid (c) acetic acid (d) both chloric acid and hydrobromic acid (e) all three solutions have the same electrical conductivity
The most electrically conductive solution among the three given solutions is hydrobromic acid, which ionizes completely in the solution and produces a high amount of ions. Therefore, option (b) hydrobromic acid is the correct answer to this question.
Acids produce ions in solution, which leads to the solution being more conductive. The more ions an acid produces, the higher the electrical conductivity of the solution. Hence, to determine the electrical conductivity of the acid, we need to know the number of ions generated by the acid in the solution. Here, three acids: hydrobromic acid, acetic acid, and chloric acid have been taken at the same concentration. So, let's check the number of ions produced by each of the acids: Hydrobromic acid: It is a strong acid that dissociates completely in the aqueous solution.
The dissociation reaction is: HBr → H+ + Br−Since it ionizes completely in the solution, the electrical conductivity of the solution would be high. Acetic acid: It is a weak acid that dissociates partially in the aqueous solution. The dissociation reaction is: CH3COOH ↔ H+ + CH3COO−Since it does not ionize completely in the solution, the electrical conductivity of the solution would be low compared to hydrobromic acid. Chloric acid: It is a strong acid that dissociates completely in the aqueous solution. The dissociation reaction is: HClO3 → H+ + ClO3−Since it ionizes completely in the solution, the electrical conductivity of the solution would be high. So, the most electrically conductive solution among the three given solutions is hydrobromic acid, which ionizes completely in the solution and produces a high amount of ions. Therefore, option (b) hydrobromic acid is the correct answer to this question.
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WILL GIVE BRANLIEST!! EASY BUT I WAS TO LAZY TO LEARN!! WILL FOREVER BE GREATFUL!!! WILL GIVE BRANLIEST!! EASY BUT I WAS TO LAZY TO LEARN!! WILL FOREVER BE GREATFUL!!!
WILL GIVE BRANLIEST!! EASY BUT I WAS TO LAZY TO LEARN!! WILL FOREVER BE GREATFUL!!!
5. What type of reaction would the heat calculation in previous question be classified as?
A) Natural
B) Chemical
C) Endothermic
D) Exothermic
7. What causes the volume to change in gases? (Choose all that apply)
A) Density
B) Temperature
C) Shape of container
D) Pressure
Answer:
for the first one we need the previous question to be able to answer it. for the second one density and temperature
Explanation:
how to find the concentration of a solution that is 100 times less than another solution
By dividing the concentration of the reference solution by 100, you will obtain the concentration of the desired solution, which is 100 times less concentrated than the reference solution.
To find the concentration of a solution that is 100 times less than another solution, you can follow these steps:
1. Determine the concentration of the reference solution. Let's denote it as [A]₀.
2. Calculate the concentration of the desired solution. Let's denote it as [A].
3. Since the desired solution is 100 times less concentrated than the reference solution, you can divide the concentration of the reference solution by 100 to obtain the concentration of the desired solution:
[A] = [A]₀ / 100
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Hydrochloric acid can dissolve solid iron according to the following reaction
Fe(s)+2HCl(aq)>FeCl2(aq) + H2(g). What minimum mass of HCl in grams would you need to dissolve a 2.3g iron bar on a padlock? Also I need to know how much H2 would be produced by the complete reaction of the iron bar (but I can ask this as a seperate question if necessary).
The mass of the HCl that is required for the reaction is 2.92 g
The mass of the hydrogen gas produced is 0.08 g
What is stoichiometry?Number of moles of the iron = 2.3 g/56 g/mol
= 0.04 moles
We have that 1 mole of the iron reacts with 2 moles of HCl
0.04 moles of iron would react with 0.04 * 2/1
= 0.08 moles
Mass of the HCl required = 0.08 moles * 36.5 g/mol
= 2.92 g
We have that the mole ratio of the iron and the hydrogen is 1:1 kit then follows that mass of the hydrogen produced would now be;
0.04 moles * 2 g/mol
= 0.08 g
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Which of the following pictures is a chemical change, and which is a
physical change? Explain in the boxes next to the picture.
Plz explain
Answer:
left is chemical because its chemicals, and right is physical because the ice cream is melting and thats physical
Explanation:
At another temperature, the rate constant is 3.25 M-2 s-1. What is the rate at this temperature for the
given concentrations?
Answer:
It's 0.00015
Explanation:
got it right on edge 2021
Which of the following chemical reactions is most likely to have the largest equilibrium constant K?
A. CH3COOH(aq) + H2O(l) CH3COO- (aq) + H3O+(aq)
B. HCl(aq) + H2O(l) H3O+(aq) + Cl-(aq)
C. H3PO4(aq) + NH3(aq) H2PO4-(aq) + NH4+(aq)
D. CH3COO- (aq) + H2O(l) CH3COOH(aq) + OH-(aq)
Answer:
The answer to this question is HCl(aq) + H2O(l) = H3O+(aq) + Cl-(aq). HCl is considered a strong acid meaning it is 100% ionized in solution. The equilibrium constant is therefore very large.
KOH is used to precipitate each of the cations from the respective solutions. Determine the minimum hydroxide required for the precipitation to begin
0.085 M Fe(NO3)2 Ksp (Fe(OH)2) = 4.87x10^-17
The minimum hydroxide concentration required for the precipitation of [tex]Fe(OH)_2[/tex] to begin is [tex]1.691* 10^-^8 M.[/tex]
How do we calculate?The balanced chemical equation for the precipitation reaction is:
[tex]Fe(OH)_2[/tex](s) ⇌ [tex]Fe^2^+[/tex](aq) + [tex]2OH^-[/tex](aq)
Ksp = [tex][Fe^2^+][OH^-]^2[/tex]
Ksp [tex]Fe(OH)_2[/tex] = [tex]4.87*10^-^1^7[/tex]
Ksp = [tex][Fe^2^+][OH^-]^2[/tex]
[tex]4.87*10^-^1^7[/tex] = (0.085)(2x)²
[tex]4.87*10^-^1^7[/tex] = 0.17x²
x² =[tex]4.87*10^-^1^7[/tex] / 0.17
x² = [tex]2.8647* 10^-^1^6[/tex]
x = [tex]1.691*10^-^8[/tex] M
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alcohol has a polar area at the top of the molecule and a large area that is not polar. the entire water molecule is polar. explain how these differences in polarity between alcohol and water can help explain why water evaporates more slowly than alcohol?
Water evaporates more slowly than alcohol because water has more surface tension and more cohesive force than alcohol, So it takes more time for water to evaporate than for alcohol.
In alcohol, only O-H present is hydrophilic i.e. polar. Apart from this alcohol has a large hydrocarbon group i.e. C-H present in it, which is non-polar in nature. As a result, the attractive force between the atoms in alcohol is less. As a result, during boiling, the bonds between the atoms vibrate and break quickly. So alcohol evaporates faster.
In water, the entire molecule is polar. So there exists a strong attractive force between them. So the cohesive force is more in the case of water as compared to that of alcohol. As water is boiled the O-H bonds start to vibrate, since the bond is stronger, it requires higher energy for boiling. Thus it evaporates slower.
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What type of reaction does this model represent?
1. single replacement
2. double replacement
3. Decomposition
4. double displacement
Answer:
1. single replacement
Explanation:
Single replacement can be represented by AB+C ⇄B+AC, which matches the picture
Double replacement and double displacement are the same kind of reaction and can be represented by AB+CD ⇄BD+AC
Decomposition reaction can be represented by AB ⇄A+B
1. Which graph represents the endothermic reaction?
2. Which graph represents the exothermic reaction?
consider the reaction 4 ko2(s) 2 co2(g) → 2 k2co3(s) 3 o2(g). how much oxygen is produced at stp if 10.5 moles of carbon dioxide are used at stp?
In the given reaction, 4 moles of KO2 react to produce 3 moles of O2. Therefore, if 10.5 moles of carbon dioxide (CO2) are used at STP, an equal amount of oxygen (O2) is produced. Hence, 10.5 moles of O2 will be generated.
According to the balanced chemical equation, the reaction 4 KO2(s) + 2 CO2(g) → 2 K2CO3(s) + 3 O2(g) shows that for every 4 moles of KO2, 3 moles of O2 are produced. Therefore, the molar ratio between KO2 and O2 is 4:3.
Since 10.5 moles of CO2 are used, we can use the stoichiometry of the reaction to determine the amount of O2 produced. As the reaction equation does not involve CO2, the amount of CO2 used does not directly affect the production of O2. Thus, 10.5 moles of CO2 will yield an equal amount of O2, resulting in 10.5 moles of O2 being produced at STP.
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why was there no reaction seen between barium nitrate and sodium chloride?
Barium nitrate and sodium chloride do not react with each other because both of them are soluble in water. The chemical equation for the reaction between barium nitrate and sodium chloride is given below.
Ba(NO₃)₂ + 2NaCl → BaCl₂ + 2NaNO₃
The reaction between barium nitrate and sodium chloride is a double displacement reaction, where barium cation is exchanged with sodium cation and nitrate anion is exchanged with chloride anion. But the reaction does not occur due to the solubility of barium nitrate and sodium chloride in water.The solution of barium nitrate and sodium chloride will remain clear and colorless with no precipitation forming. In fact, it is a method of testing the presence of sulfate ions in a solution. A small amount of barium nitrate is added to the solution to form barium sulfate. Since barium sulfate is insoluble, it forms a white precipitate.
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3. How much energy is needed to raise 45 grams of water from 40°C to 115 °C?
The specific heat capacity of ice is 2.06 J/g °C
The specific heat capacity of water is 4.18 J/g °C
The specific heat capacity of steam is 2.02 J/g °C
The heat of fusion of water is 334 J/g
The heat of vaporization of water is 2260 J/g.
Answer:
Q = 114349.5 J
Explanation:
Hello there!
In this case, since this a problem in which we need to calculate the total heat of the described process, it turns out convenient to calculate it in three steps; the first one, associated to the heating of the liquid water from 40 °C to 100 °C, next the vaporization of liquid water to steam at constant 100 °C and finally the heating of steam from 100 °C to 115 °C. In such a way, we calculate each heat as shown below:
[tex]Q_1=45g*4.18\frac{J}{g\°C}*(100\°C-40\°C)=11286J\\\\Q_2=45g* 2260 \frac{J}{g} =101700J\\\\Q_3=45*2.02\frac{J}{g\°C}*(115\°C-100\°C)=1363.5J[/tex]
Thus, the total energy turns out to be:
[tex]Q_T=11286J+101700J+1363.5J\\\\Q_T=114349.5J[/tex]
Best regards!
Select all that apply.
Which of the following are density labels?
Okg
L
09
m
og
mL
g
What is an example of an organism that undergoes binary fission?
Unicellular organisms such as amoeba and leishmania undergo binary fission.
What is binary fission?Binary fission can be described as a form of asexual reproduction where an organism divides into two, each part having one copy of genetic material.
Binary fission can be described as a kind of asexual reproduction observed in prokaryotes and a few single-celled eukaryotes. In asexual reproduction, there is a separation of the parent cell into 2 new daughter cells. This process occurs with the division and duplication into two parts.
Binary fission is a primary of reproduction in prokaryotic organisms. Binary Fission happens without spindle apparatus formation in the cell. The single DNA molecule starts replication and attaches each copy to parts of the cell membrane.
Prokaryotes and eukaryotes such as euglena reproduce via binary fission. This process is rapid, and its speed varies in species. The time needed by bacteria to double the cells it has is called known as doubling time.
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What do you divide the mass by to get the concentration of a solute?
You divide by the mass of the solution.
Percent by mass is the mass of the solute divided by the mass of the solution, multiplied by 100.
Example:
You dissolve a 4.00 g sugar cube in 350 mL of tea at 80 °C. The density of water at 80 °C is 0.975 g/mL. What is the percent by mass of sugar in the solution?
Solution
Step 1 — Determine mass of the solute.
The solute is the sugar cube. Mass of solute = 4.00 g.
Step 2 — Determine mass of solvent.
The solvent is the 80 °C water. Use the density of the water to find the mass.
mass of solvent = 350 mL ×
0.975
g
1
mL
= 341 g
Step 3— Determine the total mass of the solution
mass of solution = mass of solute + mass of solvent = 4.00 g + 341 g = 345 g
Step 4 — Determine percent composition by mass of the sugar solution.
% by mass =
mass of solute
mass of solution
× 100 % =
4.00
g
345
g
× 100 % = 1.159 %
The percent composition by mass of the sugar solution is 1.159 %.
How does this equation show that transmutation has taken place? 238 U – 334 Th + He 92 O A. The numbers of neither nucleons nor atoms are conserved. B. One element changes into another. O C. Atoms of different elements are present. O D. The number of nucleons is not conserved.
Answer:
B. One element changes into another.
Explanation:
We can see from the equation that uranium is changed to thorium and helium. Transmutation is the process by which one element is changed to another through radioactive decay, nuclear bombardment, or other similar processes.
Answer:b
Explanation:
draw the major e2 reaction product formed when (1r,2s,4s)‑2‑chloro‑4‑methyl‑1‑(propan‑2‑yl)cyclohexane reacts with hydroxide ion in dmso. chirality is graded.
The major E2 reaction product formed when (1R,2S,4S)-2-chloro-4-methyl-1-(propan-2-yl)cyclohexane reacts with hydroxide ion in DMSO is (1S,2R,4S)-2-methyl-1-(propan-2-yl)cyclohexene.
In an E2 (elimination) reaction, a hydrogen atom and a leaving group are removed from adjacent carbon atoms, resulting in the formation of a double bond. In this case, the leaving group is the chloride ion (Cl-) and the hydrogen atom is removed from the carbon adjacent to the chlorine atom.
The given starting compound, (1R,2S,4S)-2-chloro-4-methyl-1-(propan-2-yl)cyclohexane, has a chiral center at carbon 2, which is marked as (S). When the hydroxide ion (OH-) attacks the carbon adjacent to the chlorine atom, the chlorine leaves and a hydrogen from the adjacent carbon is also removed. The resulting product is (1S,2R,4S)-2-methyl-1-(propan-2-yl)cyclohexene.
It's important to note that the stereochemistry of the starting compound and the resulting product is represented by the (R) and (S) designations, indicating the arrangement of the substituents around the chiral carbon atoms.
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a. Identify the different parts of the chemical equation below. (2 points) A(s) B(l) C(g) D(aq) 1. A: _________________________
2. B: _________________________
3. C: _________________________
4. D: _________________________
5. (s): _________________________
6. (l): _________________________
7. (g): _________________________
The different parts of the chemical equation below are identified as follows:
1. A: Solid
2. B: Liquid
3. C: Gas
4. D: Aqueous
5. (s): Solid
6. (l): Liquid
7. (g): Gas
A chemical equation is a symbolic representation of a chemical reaction where reactants are written on the left side and products on the right side. These reactants and products are identified with their respective states such as solid, liquid, gas, and aqueous.
The symbols for the physical states of the reactants and products are included in parentheses, alongside their respective chemical formulas.
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Pls someone help me hurry pls someone?????
Answer:
Becxause there is no whee5r else for the flame to go out fromk
Explanation:
NaCl
Na = 1
Cl=1
Answer:
19. because fire needs oxygen or air to keep the fire burning.
20.A molecule of sodium chloride, NaCl, consists of one atom each of sodium and chlorine. Hence, each molecule of NaCl has 2 atoms total. Similarly, we can calculate the total number of atoms in 1 mole of sodium chloride. Since 1 molecule contains 1 atom each of Na and Cl, 1 mole of NaCl will contain 1 mole each of Na and Cl.
Explanation:
Hope this helps!
What type pf asexual reproduction produces the most offspring?
Binary Fission
Budding
Sporulation
thats kinda hot not even gon'
The characteristics of metallic bonds fit nicley into a predictable pattern. True or False?
Answer:
True
Explanation:
DON'T GIVE BRAINLIEST TO THE FILE EXPLOITER!!!!
Calculate the value of the equilibrium constant, kp, at 298k. N2(g) + 2NO2(g) ↹ 2NO2(g) from the following Kp values at 298 K
N2(g) + O2(g) ↹ 2NO(g), Kp = 4,0 x 10^-31 2NO(g) + O2(g) ↹ 2 NO2(g), Kp = 2.4 x 10^12
After considering the given data we conclude that the value of the equilibrium constant, Kp, for the reaction [tex]N_2(g) + 2NO_2(g)--- > 2NO_2(g)[/tex] at 298 K is [tex]4.8*10^{-17}[/tex].
To evaluate the value of the equilibrium constant, Kp, for the reaction [tex]N_2(g) + 2NO_2(g)--- > 2NO_2(g)[/tex] at 298 K, we can apply the following steps:
Write the balanced chemical equation for the reaction.
[tex]N_2(g) + 2NO_2(g) - - - > 2NO_2(g)[/tex]
Write the expression for Kp for each of the two reactions given.
[tex]Kp_1 = [NO]^2/[N_2][O_2][/tex]
[tex]Kp_2 = [NO_2]^2/[NO]^2[O_2][/tex]
Here,[tex][NO], [N_2], [O_2], and [NO_2][/tex]are the partial pressures of the respective species at equilibrium.
Stage the given values of [tex]Kp_1[/tex] and [tex]Kp_2[/tex] into the expression for Kp for the desired reaction.
[tex]Kp = Kp_2/Kp_1 = ([NO_2]^2/[NO]^2[O_2])/([NO]^2/[N_2][O_2]) = ([NO_2]^2[N_2])/[NO]^4[/tex]
Restructure the expression for Kp to solve for the unknown partial pressure of [tex]NO_2[/tex].
[tex][NO_2]^2 = Kp[NO]^4/[N_2][/tex]
Stage the given values of [tex]Kp_1[/tex] and [tex]Kp_2[/tex], and the given partial pressures of N2 and O2, into the expression for [NO].
[tex][NO] = \sqrt(Kp_1[N_2][O_2])[/tex]
Stage the calculated value of [NO] into the expression for[tex][NO_2][/tex] to obtain the equilibrium partial pressure of [tex]NO_2[/tex].
[tex][NO_2]^2 = Kp[NO]^4/[N_2][/tex]
[tex][NO_2]^2 = (2.4*10^{12} )(4.0*10^{-31} )([N_2][O_2])^2/[N_2][/tex]
[tex][NO_2]^2 = 9.6*10^{-19} [N_2][O_2]^2[/tex]
[tex][NO_2] = \sqrt(9.6*10^{-19} [N_2][O_2]^2)[/tex]
[tex][NO_2] = 3.1*10^{-10} atm[/tex]
Stage the evaluated values of [NO] and[tex][NO_2][/tex] into the expression for Kp to obtain the equilibrium constant.
[tex]Kp = ([NO_2]^2[N_2])/[NO]^4[/tex]
[tex]Kp = (9.6*10^{-19} )(3.1*10^{-10} )^2/[/\sqrt(4.0*10^{-31*1} atm)]^4[/tex]
[tex]Kp = 4.8*10^{-17}[/tex]
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What is the hybridization of bromine in each of thefollowing:
a)BrF3
b)BrO2-
c)BrF5
The bromine atom in BrF3 is sp3d hybridized, in BrO2- it is sp3 hybridized, and in BrF5 it is sp3d2 hybridized.
The hybridization of bromine in each of the following compounds is as follows:
a) BrF3:
The central atom, bromine (Br), in BrF3 undergoes sp3d hybridization. It forms three sigma bonds with three fluorine atoms and has two lone pairs of electrons. The three sigma bonds are formed by overlapping of the sp3d hybrid orbitals of bromine with the 2p orbitals of the fluorine atoms.
b) BrO2-:
The central atom, bromine (Br), in BrO2- undergoes sp3 hybridization. It forms two sigma bonds with two oxygen atoms and has two lone pairs of electrons. The two sigma bonds are formed by overlapping of the sp3 hybrid orbitals of bromine with the 2p orbitals of the oxygen atoms.
c) BrF5:
The central atom, bromine (Br), in BrF5 undergoes sp3d2 hybridization. It forms five sigma bonds with five fluorine atoms and has one lone pair of electrons. The five sigma bonds are formed by overlapping of the sp3d2 hybrid orbitals of bromine with the 2p orbitals of the fluorine atoms.
Hybridization is a concept used to describe the mixing of atomic orbitals to form new hybrid orbitals in a molecule. It helps to explain the molecular geometry and bonding in the molecule. The hybridization of an atom depends on the number of sigma bonds it forms and the number of lone pairs of electrons it possesses.
In summary, the bromine atom in BrF3 is sp3d hybridized, in BrO2- it is sp3 hybridized, and in BrF5 it is sp3d2 hybridized. The hybridization of bromine determines the shape and geometry of the molecules and provides insights into the nature of their chemical bonding.
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Here is the skeleton reaction for combustion of methane (natural gas)
CH4+O2→CO2+H2O
What are the reactants of this reaction?
Please help me :(
Answer:
CH4 and O2
Explanation:
The reactants of a chemical reaction are those that are on the left side of the chemical equation. In this case, methane (CH4) and oxygen (O2) which are on the left side, are the reactants.