In a controlled experiment, the factor tested is called the [tex]\boxed{{\text{B}}{\text{. independent variable}}}[/tex].
Further Explanation:
A procedure that is performed in order to support, disprove or validate a hypothesis is known as an experiment. A hypothesis is an idea or thought that needs to be tested with the help of experiments.
Types of experiments:
1. Controlled experiments
The type of experiment that is used for comparing the results of experimental samples with the control samples is called a controlled experiment. Such experiments involve a drug trial. The experimental group will be the one that receives the drug and the other one receiving regular treatment will be the controlled group. The experimental group is also known as the treatment group. Another example of controlled experiments is the protein assay.
2. Natural experiments
These are also called quasi-experiments. These are performed by exposing individuals to the conditions that are governed by nature. Experiments involving weather changes and natural disasters are examples of natural experiments.
3. Field experiments
These are quite different from the experiments performed in the laboratory. Such experiments are usually performed in social studies. These have higher external validity as compared to normal lab experiments. Economic analysis of health and education are some examples of such experiments.
The variable that can be changed by the investigator is called the independent variable while the variable is the one that is affected by the changes in experimental conditions. All the variables in a controlled experiment are kept constant; except for the factor that is to be tested. Such a factor is called the independent variable or the experimental variable.
Learn More:
What is the main purpose of conducting experiments? https://brainly.com/question/5096428 What is the percentage error in the experiment? https://brainly.com/question/11181911
Answer Details:
Grade: Senior School
Chapter: Keys to studying chemistry
Subject: Chemistry
Keywords: experiment, hypothesis, controlled experiment, natural experiment, field experiments, dependent variable, independent variable, quasi-experiments.
Determine the [oh] concentration in a 0.169 m ca(oh)2 solution. 0.338 m 0.169 m 5.92 x 10-14 m 2.96 x 10-14 m 0.298 m
The [OH-] concentration in the 0.169 M Ca(OH)2 solution is 0.0088 M. The pOH of the solution is 2.055, and the pH is 11.945.
Explanation:We begin by determining the concentration of hydroxide ions, [OH-], in the Ca(OH)2 solution. Since Ca(OH)2 is a strong base, there are two OH ions for every formula unit dissolved, so the concentration of OH- is 2 times the concentration of Ca(OH)2. Therefore, [OH-] = 2 × 0.0044 M = 0.0088 M.
The concentration of hydroxide ions can be used to calculate the pOH of the solution. The pOH is obtained by taking the negative logarithm of [OH-]. In this case, pOH = -log(0.0088) = 2.055.
To calculate the pH of the solution, subtract the pOH from 14. pH = 14 - 2.055 = 11.945.
The Valence Electrons of an Atom of Which Element would feel a Greater Effective Nuclear Charge than the Valence?
The Valence Electrons of an Atom of which element would feel a greater effective Nuclear Charge than the valence electrons of a Boron (B) atom?
Aluminum (Al)
Beryllium (Be)
Hydrogen (H)
Carbon (C)
Carbon's valence electrons feel a greater effective nuclear charge than those of a Boron atom because Carbon has one more proton without significantly increasing the shielding effect, leading to a stronger pull on the valence electrons.
Explanation:The question asks which element's valence electrons feel a greater effective nuclear charge than those of a Boron (B) atom. To answer this, one must understand how shielding and effective nuclear charge work. As we go from left to right across a period in the periodic table, while the number of core electrons remains the same, the nuclear charge increases. This means the valence electrons feel a stronger pull from the nucleus since they are not effectively shielded by the same number of core electrons. Comparing Boron with Aluminum (Al), Beryllium (Be), Hydrogen (H), and Carbon (C), we find that Carbon, having one more proton than Boron, does not increase the shielding effect significantly, which leads to its valence electrons feeling a greater effective nuclear charge than Boron's. Therefore, Carbon (C) is the correct response.
Predict how the addition of a catalyst would affect the rate of the reaction below, and explain your prediction. h2 (g) + i2 (g) 2hi
Explanation:
A catalyst helps in increasing the rate of a chemical reaction without itself getting consumed in the reaction.
Basically, a catalyst decreases the activation energy so that reactant molecules can easily participate in the reaction.
For example, when a catalyst is added to [tex]H_{2}(g) + I_{2}(g) \rightarrow 2HI[/tex] then there will be a decrease in activation energy and both reactants (hydrogen and iodine) can easily participate in the chemical reaction.
As a result, formation of product (HI) becomes faster.
Thus, we can conclude that a catalyst helps in increasing the rate of a reaction.
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 = ?
Final answer:
To calculate the net equilibrium constant for the dissolution of silver chloride in ammonia, the individual constants for the dissolution of AgCl and the formation of [tex][Ag(NH_3)_2]^+[/tex] are multiplied, yielding Knet = 2.4 x 10^-3.
Explanation:
The solubility of silver chloride (AgCl) in ammonia solution can be analyzed using the concept of equilibrium constants. The equilibrium constant (K) for the dissolution of AgCl in water is given as 1.6 x 10-10, and the formation constant (K2) of the complex ion [tex][Ag(NH_3)_2]^+[/tex] is 1.5 x 107. To find the net equilibrium constant (Knet) for the overall reaction where AgCl dissolves in the presence of NH3 to form the complex ion and release Cl-, we can multiply the individual constants: K1 * K2. Thus, Knet = (1.6 x 10-10)(1.5 x 107) = 2.4 x 10-3.
What is the H+ if the pH of a solution is 1.65?
Answer:
[H⁺] = 2.2 × 10⁻²
Explanation:
pH = -log [H⁺]
10∧-pH = [H⁺]
[H⁺] = 10⁻¹°⁶⁵
[H⁺] = 0.0224
[H⁺] = 2.2 × 10⁻²
So the concentration of hydrogen in solution of 1.65 pH is 2.2 × 10⁻².
Nuclear fusion of hydrogen into helium occurs in the
Nuclear fusion of hydrogen into helium occurs in the core of stars, specifically in their stellar cores.
This process is known as stellar nucleosynthesis and is the primary source of energy production in stars. The intense heat and pressure in the core of a star allow hydrogen nuclei (protons) to overcome their mutual electrostatic repulsion and undergo fusion reactions. It results in the formation of helium nuclei.
The most common fusion reaction in stars is the proton-proton chain, which involves a series of steps leading to the conversion of four hydrogen nuclei into one helium nucleus.
Learn more about nuclear fusion, here:
https://brainly.com/question/14019172
#SPJ6
Constance is making a vegetable soup that contains carrots, beans, water, salt, pepper, bits of ham, and onions. the soup has to cook for 4 hours. while the soup is cooking, what will happen to some of the minerals that are in its ingredients?
Cooking can alter the structure of proteins and destroy certain vitamins in the soup ingredients, while salt acts as a preservative to prevent bacterial growth.
Explanation:When the soup is cooking, some of the minerals in its ingredients may undergo changes. For example, cooking can alter the structure of proteins in the ham and vegetables, making them easier to digest. However, cooking can also destroy certain vitamins, such as vitamins B and C in vegetables. Additionally, salt, which is a mineral, is used as a preservative in the soup, preventing the growth of bacteria by dehydrating them through osmotic pressure.
QUESTION 5
In their compounds, metals:
are assigned positive oxidation numbers
are assigned negative oxidation numbers
are assigned oxidation numbers of zero
can be assigned any oxidation number that balances the equation
QUESTION 6
In the reaction, Zn (s) + Fe+2 (aq) Imported Asset Zn+2 (aq) + Fe (s), the oxidizing agent is:
the Zn
the Fe
the Zn+2
the Fe+2
In compounds, metals have positive oxidation numbers; for instance, iron has a +2 oxidation number in FeO. In the reaction Zn + Fe2+ → Zn2+ + Fe, Fe2+ is the oxidizing agent as it gains electrons and is reduced.
In their compounds, metals are generally assigned positive oxidation numbers because they tend to lose electrons and form cations. For example, in FeO, iron has an oxidation number of +2 (Fe2+), correctly balancing the -2 charge from oxygen to result in a neutral compound.
Regarding the reaction Zn (s) + Fe2+ (aq) → Zn2+ (aq) + Fe (s), the oxidizing agent is the species that is reduced by gaining electrons. In this case, Fe2+ is the oxidizing agent because it gains electrons from Zn to form Fe (s). The Zn is oxidized to Zn2+, making it the reducing agent.
Brainliest if answered in the next 5 minutes.
Identify the balanced combination equation.
Cl2O5 + H2O ⟶ 2HClO3
2Fe(OH)3 ⟶ Fe2O3 + 3H2O
Cl2O5 + 3H2O ⟶ HClO3
2Fe(OH)3 ⟶ 2FeO3 + 3H2O
Answer: The correct answer is [tex]Cl_2O_5+H_2O\rightarrow 2HClO_3[/tex]
Explanation:
Combination reaction is defined as the type of reaction in which teo smaller compounds join or combine together to form a large compound.
General representation is given by:
[tex]A+B\rightarrow AB[/tex]
A balanced chemical equation always follow law of conservation of mass. The law states that the total number of individual atoms on the reactant side is always equal to the total number of atoms on the product side.
From the given options:
The equation that is an example of balanced combination reaction is
[tex]Cl_2O_5+H_2O\rightarrow 2HClO_3[/tex]
What observations would lead you to believe that the ink is actually a mixture?
Describe one chemical property of Group 1 metals that results from the atoms of each metal having only one valence electron.
A chemical property of Group 1 metals that results from the atoms of each metal having only one valence electron is electronegativity.
Group 1 elements are also known as alkali metals. They include sodium, lithium, potassium, cesium, francium, and rubidium. They can be found in seawater.
A chemical property of Group 1 metals that results from the atoms of each metal having only one valence electron is electronegativity. This means the tendency for the atoms to be able to attract electrons.
Read related link on:
https://brainly.com/question/2827543
What is the concentration of hydroxide ions in a solution with a pH of 5.24?
5.75 × 10-6
1.74 × 10-9
1.55 × 10-7
4.54 × 10-4
Answer:
The concentration of hydroxide ions in a solution with a pH of 5.24 is [tex]1.74\times 10^{-9} M[/tex].
Explanation:
The pH of the solution is defined as negative logarithm of [tex]H^+[/tex] ions in solution.
[tex]pH=-\log[H^+][/tex]
The pH of the solution = 5.24
Sum of pH and pOH is equal to 14.
[tex]pH+pOH=14[/tex]
[tex]pOH=14-pH=14-5.24=8.76[/tex]
[tex]pOH=-\log[OH^-][/tex]
[tex]8,76=\log[OH^-][/tex]
[tex][OH^-]=1.7378\times 10^{-9}\approx=1.74\times 10^{-9} M[/tex]
The concentration of hydroxide ions in a solution with a pH of 5.24 is [tex]1.74\times 10^{-9} M[/tex].
Which best describes how the current scientific model of the atom was developed the model was the result of hundreds of years of experiments recent experiments in a valid in most of the book of last 200 years most of the discoveries from the early nineteen-hundreds was shown to be incorrect new experiments for ignored or they did not agree with the accepted Theory
Answer:
The model was the result of hundreds of years of experiments. however we have had modifications.
Explanation:
What volume of 0.0250 m calcium hydroxide is required to neutralize 33.50 ml of 0.0200 m nitric acid?
How is the volatility of a substance related to the intermolecular forces present within the substance? how is the volatility of a substance related to the intermolecular forces present within the substance? the weaker the intermolecular forces, the more likely it is that molecules are to evaporate at a given temperature, making the liquid more volatile. the volatility of a substance does not depend on the intermolecular forces present within the substance. the stronger the intermolecular forces, the more likely it is that molecules are to evaporate at a given temperature, making the liquid more volatile?
The less volatile a chemical is, the stronger the intermolecular interactions must be overcome before they can be overcome using energy or temperature.
What is intermolecular interaction ?Intermolecular forces, such as the electromagnetic forces of attraction or repulsion that act between atoms and other kinds of nearby particles, such as atoms or ions, mediate interactions between molecules.
Intermolecular forces come in five flavors: ion-induced dipole forces, dipole-induced dipole forces, induced dipole forces, and dipole-dipole forces. Ions and polar (dipole) molecules are held together by ion-dipole forces.
Ionic bonds, hydrogen bonds, Van der Waals dipole-dipole interactions, and Van der Waals dispersion forces are the four main intermolecular force.
Thus, The weaker the intermolecular interactions, the less energy is needed to overcome them and convert the substance from liquid to vapor or gas.
To learn more about intermolecular interaction, follow the link;
https://brainly.com/question/14894882
#SPJ2
How is the rate of evaporation of a liquid affected by (a) temperature, (b) the surface area of liquid exposed to air, (c) intermolecular forces??
Final answer:
The rate of evaporation is higher with increased temperature, greater surface area, and weaker intermolecular forces; temperature rise decreases the surface tension of water.
Explanation:
The rate of evaporation of a liquid is influenced by several factors. Let us look at these factors one by one:
Temperature: As temperature increases, the average kinetic energy of the molecules also increases. This means more molecules have sufficient energy to overcome the intermolecular forces and escape into the gas phase, thus increasing the rate of evaporation.
Surface Area: The greater the surface area exposed to air, the more molecules are available to evaporate at any given time, leading to a higher rate of evaporation.
Intermolecular Forces: Stronger intermolecular forces make it more difficult for molecules to escape into the gas phase, resulting in lower rates of evaporation. Conversely, weaker intermolecular forces enhance the rate of evaporation.
If we specifically look at how temperature affects surface tension, we note that an increase in temperature will generally result in a decrease in the surface tension of water. This happens because as the temperature rises, the molecules have more kinetic energy, which disrupts the cohesive intermolecular forces between water molecules, thus decreasing surface tension.
Calculate the pressure in atmospheres exerted by 10.0moles of hydrogen gas at 293 kelvins if it is stored in a 7.50 liter container. Your value should be a decimal number written to three significant figures. Given: R= 0.08205 liter x atmosphere/mole x kelvin
Answer:
The correct answer is 32.1 atm. If you rearrange the ideal gas law equation to find pressure (P) and substitute the known values for the rest of the variables (n, T, and V), we get pressure equal to 32.1 atm.
Explanation:
I don't cap. Anyways good luck! I believe in you!
A chemist dissolves 192.mg of pure sodium hydroxide in enough water to make up 150.ml of solution. calculate the ph of the solution.
An organic compound in which a carbonyl group is bonded to two different carbon atoms is a(n) amide. aldehyde. ketone. ester.
Answer: ketone
Explanation:
Functional groups are specific group of atoms within molecules that are responsible for the characteristic chemical reactions of those molecules.
1. Amides have functional group [tex]-O=C-NH_2[/tex].
Example: Ethanamide with molecular formula [tex]CH_3CONH_2[/tex]
2. Aldehydes have functional group [tex]-O=CH[/tex].
Example: Ethanal with molecular formula [tex]CH_3CHO[/tex]
3. Ketones have functional group [tex]-C=O[/tex].
Example: Propanone with molecular formula [tex]CH_3COCH_3[/tex]
4. Esters have functional group [tex]-O=C-OR[/tex].
Example: methyl ethanoate with molecular formula [tex]CH_3COOCH_3[/tex]
What is the molar mass of (NH4)2O? Explain how you calculated this value.
The molar mass of (NH₄)₂O (ammonium oxide) is 52.10 g/mol.
To calculate the molar mass of (NH₄)₂O (ammonium oxide), we need to determine the total sum of the atomic masses of all the atoms in the chemical formula.
The atomic masses are as follows:
N (Nitrogen) = 14.01 g/mol
H (Hydrogen) = 1.01 g/mol
O (Oxygen) = 16.00 g/mol
Now, let's calculate the molar mass of (NH₄)₂O:
Molar mass of (NH₄)₂O = (2 x N) + (8 x H) + (1 x O)
Molar mass of (NH₄)₂O = (2 x 14.01 g/mol) + (8 x 1.01 g/mol) + (1 x 16.00 g/mol)
Molar mass of (NH₄)₂O = 28.02 g/mol + 8.08 g/mol + 16.00 g/mol
Molar mass of (NH₄)₂O = 52.10 g/mol
So, the molar mass of (NH₄)₂O (ammonium oxide) is approximately 52.10 g/mol.
To know more about molar mass here
https://brainly.com/question/31545539
#SPJ6
what is the percent composition in chloric acid (HClO3)?
Which of the following changes requires an oxidizing agent?
O2 yields 2O2-
SO3 yields SO42-
2F- yields F2
MnO2 yields Mn2+
Answer : The correct option is, [tex]2F^-\rightarrow F_2+2e^-[/tex]
Explanation :
Oxidation reaction : It is defined as the reaction in which a substance looses its electrons. In the oxidation reaction, the oxidation state of an element increases. Or we can say that in oxidation, the loss of electrons takes place.
Oxidizing agent : It is defined as the substance which has ability to oxidize the other substances by gaining electrons.
Reduction reaction : It is defined as the reaction in which a substance gains electrons. In the reduction reaction, the oxidation state of an element decreases. Or we can say that in reduction, the gain of electrons takes place.
Reducing agent : It is defined as the substance which has ability to reduce the other substances by losing electrons.
From the given options, we conclude that
(1) [tex]O_2+4e^-\rightarrow 2O^{2-}[/tex]
(2) [tex]SO_3+H_2O\rightarrow SO_4^{2-}+2H^+[/tex]
(3) [tex]MnO_2+4H^++2e^-\rightarrow Mn^{2+}+2H_2O[/tex]
The reaction 1, 2 and 3 shows the reduction reaction. So, it requires a reducing agent.
(4) [tex]2F^-\rightarrow F_2+2e^-[/tex]
The reaction 4 shows the oxidation reaction. Therefore, it requires an oxidizing agent.
Therefore, the correct option is, [tex]2F^-\rightarrow F_2+2e^-[/tex]
Water beads up on waxy surfaces because of a ___________ degree of adhesion with the surface?
high
low
the correct answer is low
What elements make up molecules of sugar?
A certain weak acid, ha, has a ka value of 8.4×10−7. calculate the percent ionization of ha in a 0.10 m solution
To
determine the percent ionization of the acid given, we make use of the acid
equilibrium constant (Ka) given. It is the ratio of the equilibrium
concentrations of the dissociated ions and the acid. The dissociation reaction
of the HF acid would be as follows:
HA = H+ + A-
The acid equilibrum constant would be expressed as follows:
Ka = [H+][A-] / [HA] = 8.4 x 10^-7
To determine the equilibrium concentrations we use the ICE table,
HF
H+ A-
I 0.10 0
0
C -x +x
+x
---------------------------------------------
E 0.10-x x
x
8.4 x 10^-7= [H+][A-] / [HA]
8.4 x 10^-7 = [x][x] / [0.10-x]
Solving for x,
x = 0.0002894 = [H+] = [A-]
percent ionization = 0.0002894 / 0.10 x 100 = 0.289%
An elixir of ferrous sulfate contains 220 mg of ferrous sulfate in each 5 ml. if each milligram of ferrous sulfate contains the equivalent of 0.2 mg of elemental iron, how many milligrams of elemental iron would be represented in each 5 ml of the elixir?
Each 5 ml of the ferrous sulfate elixir contains 44 milligrams of elemental iron.
Explanation:The question is asking for the amount of elemental iron in 5 ml of ferrous sulfate elixir. Given that each milligram of ferrous sulfate contains 0.2 mg of elemental iron and there's 220 mg of ferrous sulfate present in every 5 ml, a simple multiplication would give the quantity of elemental iron in each 5 ml of the elixir.
Formula: Ferrous Sulfate (mg) x Elemental Iron/Ferrous Sulfate = Elemental Iron (mg)
Using the given values, it goes as follows: 220 mg x 0.2 = 44 mg. Consequently, each 5 ml of the elixir contains 44 milligrams of elemental iron.
Learn more about elemental iron content here:https://brainly.com/question/33060172
#SPJ12
What is the only subatomic particle that is directly involved in the chemical reactions?
Matter appears to be conserved in chemical reactions but not in nuclear reactions because:
A. the law of conservation of matter only applies to a limited number of chemical and nuclear reactions
B. the law of conservation of mass-energy applies only to nuclear reactions
C. in nuclear reactions, particles move too quickly to have their masses measured
D. in nuclear reactions the changes in mass are large enough to be detected
I think it's A? Just tell me if I'm right, and if I'm wrong, point me in the right direction :)
What is the molarity of a sodium hydroxide solution if 35.4 ml of this solution is neutralized by 24.2 ml of 1.19 m sulfuric acid solution?
The molarity of the sodium hydroxide solution is approximately 0.818 M.
Explanation:To determine the molarity of the sodium hydroxide solution, we can use the equation for the reaction between sodium hydroxide and sulfuric acid: 2NaOH + H₂SO4 → Na₂SO4 + 2H₂O. From the balanced equation, we can see that the ratio of NaOH to H₂SO4 is 2:1. Thus, if 24.2 mL of 1.19 M sulfuric acid solution neutralizes 35.4 mL of the sodium hydroxide solution, we can set up the following equation:
Molarity of NaOH × Volume of NaOH = Molarity of H₂SO4 × Volume of H₂SO4
Molarity of NaOH × 35.4 mL = 1.19 M × 24.2 mL
Rearranging the equation, we get:
Molarity of NaOH = (1.19 M × 24.2 mL) / 35.4 mL
Calculating the molarity of NaOH, we find that it is approximately 0.818 M.
The national drug code number (NDC) of the drug is included in this section of a drug monograph