Answer:
The correct option is A
Explanation:
An independent variable is a variable that is intentionally altered (directly or indirectly) and is not dependent on another variable in the course of an experiment. Unlike the independent variable, the dependent variable depends or is presumed to depend on the altered independent variables.
From the explanation above, it can be deduced that the concentration of the catalase is the independent variable as it was intentionally altered (by using different concentrations) in the course of the experiment. The amount of oxygen given off is the dependent variable here
When water ionizes, it produces equal amounts of hydrogen and hydroxide ions that can reassociation with each other. The pH of water is:
Answer:
Explanation:
ionic product of water Kw = 10⁻¹⁴
[H⁺] [ OH⁻ ] = 10⁻¹⁴
[H⁺] ² = 10⁻¹⁴
[H⁺] = 10⁻⁷
Water dissociates as follows .
H₂O ⇄ H⁺ + OH⁻
10⁻⁷M 10⁻⁷ M
pH = - log [H⁺]
= - log [ 10⁻⁷ ]
= 7 .
So pH of pure water solution = 7 .
The pH of pure water is 7, which is considered neutral because it is neither acidic nor alkaline.
Determining the pH of waterWhen pure water ionizes, it produces equal amounts of hydrogen ions (H+) and hydroxide ions (OH-), according to the equation:
H2O ⇌ H+ + OH-
However, the concentration of H+ and OH- ions in pure water is very low, and the product of their concentrations is always equal to a fixed value at a given temperature. This value is 1 x [tex]10^-14[/tex] at 25°C.
The pH of water is a measure of its acidity or alkalinity, and is defined as the negative logarithm base 10 of the hydrogen ion concentration.
In pure water at 25°C, the hydrogen ion concentration is equal to the hydroxide ion concentration, and both are equal to 1 x [tex]10^-7[/tex] moles per liter.
Therefore, the pH of pure water at 25°C is:
pH = -log[H+]
= -log[1 x [tex]10^-7[/tex]]
= 7
Thus, the pH of pure water is 7, which is considered neutral because it is neither acidic nor alkaline.
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Which substance has AHf defined as O kJ/mol?
A. H20 (s)
B. Ne (I)
C. F2 (g)
D. CO2 (g)
It’s C.
Answer:
(C). is the answer, I think
Fluorine in gaseous form is a substance which has atoms far away from one another has ΔHf as 0 kj/mole.
What is an atom?An atom is defined as the smallest unit of matter which forms an element. Every form of matter whether it is solid,liquid , gas is made up of atoms . Each atom has a nucleus which is composed of protons and neutrons and shells in which the electrons revolve.
The protons are positively charged and neutrons are neutral particles and hence the nucleus is positively charged. The electrons which revolve around the nucleus are negatively charged and hence the atom as a whole is neutral and stable due to presence of oppositely charged particles.
Atoms of the same element are similar as they have number of sub- atomic particles which on combination do not alter the chemical properties of the substances.
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I really need someone to explain how to find the average atomic mass.... the gizmos was really confusing because they also had weighted mass.
Answer:
Option C. 52.057
Explanation:
The following data were obtained from the question:
Isotope >> Mass number > Percentage
A (Cr-50) > 50 >>>>>>>>>> 4.3
B (Cr-52) > 52 >>>>>>>>>> 83.8
C (Cr-53) > 53 >>>>>>>>>> 9.5
D (Cr-54) > 54 >>>>>>>>>> 2.4
Average atomic mass =?
The average atomic mass of chromium, Cr can be obtained as follow:
Average atomic mass = [(Mass of A × A%) /100] + [(Mass of B × B%) /100] + [(Mass of C × C%) /100] + [(Mass of D × D%) /100]
Atomic mass of Cr = [50×4.3)/100] + [52×83.8)/100] + [53×9.5)/100] + [54×2.4)/100]
= 2.15 + 43.576 + 5.035 + 1.296
Atomic mass of Cr = 52.057
Therefore, the atomic mass of chromium, Cr is 52.057
A student measures the mass of a 6.0 cm3 block of brown sugar to be 10.0 g. What is the density of the brown sugar?
Answer:
1.67g/cm3
Explanation:
The formula for density is [tex]d=\frac{m}{v}[/tex] . The m variable stands for mass and the v variable stands for volume.
The mass of the brown sugar is 10.0g and the volume is 6.0cm3, so we can plug those values into the equation.
[tex]d=\frac{10g}{6cm^{3} }[/tex]
[tex]d=1.67[/tex][tex]\frac{g}{cm^{3} }[/tex]
Rounded to 3 significant figures, the density of the block of brown sugar is 1.67 g/cm3. If the mass is in grams and the volume is in cm3, the unit for the final answer is [tex]\frac{g}{cm^{3} }[/tex] (grams per centimetres cubed).
Answer:
16g
Explanation:
Question 1 (True/False Worth 2 points)
(02.02 MC)
Salt dissolving in water is a physical change.
O True
O False
Answer:
True
Explanation:
Any substance dissolving a solid (salt) in liquid (water) is a physical change.
Salt in water, is a physical change because only the state of the matter has changed.
Answer:
true
Explanation:
uwu
Fluorine (a halogen) is______
because it has______
outer shell electrons.
A. Slightly Reactive, 9
B. Very Reactive, 7
C. Very Reactive, 1
D. Inert, 7
Answer:
The correct answer would be B.
Fluorine (a halogen) is very reactive because it has 7 outer shell electrons.
Explanation:
It's located at the top of the Halogen Group in the periodic table and it's the most electronegative element, this makes it very reactive.
I hope this helps you:)
Fluorine (a halogen) is Very Reactive because it has 7 outer shell electrons.Hence, option (D) is correct.
What are Halogen ?The halogens are a group in the periodic table consisting of five or six chemically related elements: fluorine, chlorine, bromine, iodine (I), and astatine.
The artificially created element 117, tennessine, may also be a halogen. In the modern IUPAC nomenclature, this group is known as group 17
Therefore, Fluorine (a halogen) is Very Reactive because it has 7 outer shell electrons. Hence, option (D) is correct.
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HELP PLZ!!! Which must be kept in mind when determining if an explanation is correct? whether people reading the explanation agree the information that is on the Internet that there may be more than one way to interpret data whether a person of authority says it is correct
Answer: C. that there may be more than one way to interpret data
Enge 2020 C is the correct answer
A chemist compresses a 1.8 L sample of carbon dioxide gas at 2.4 atm to a final volume of 1.5 L. Assuming the temperature is constant,what is the final pressure,in arm,exerted by the gas
Answer:
THE PRESSURE EXERTED BY THE GAS IS THEREFORE 2.88 atm.
Explanation:
Boyle's law states that at constant temperature, the volume of a given mass of gas is inversely proportional to the pressure of the gas.
Mathematically, P1 V1 = P2 V2
Write out the values of the variables given:
P1 = 2.4 atm
V1 = 1.8 L
V2 = 1.5 L
P2 = unknown
Re-arranging the variables by making P2 the subject of the equation, we have:
P2 = P1 V1 / V2
P2 = 2.4 * 1.8 / 1.5
P2 = 2.9=88 atm
Hence, the pressure exerted by the gas is therefore 2.88 atm
Limitations of Lewis dot structure
Answer:
Limitations of Lewis structures: resonance structures and violations of the octet rule (odd electron, hypovalent and hypervalent molecules). (1) Shapes of simple molecules with “central” atoms. (2) Configuration: the position of atoms in space about a central atom. The VSEPR theory of configuration.
Limitations of Lewis dot structure are it will not explain the shape and type of attraction force present within the molecule.
What is Lewis dot structure?Lewis dot structure of any molecule gives idea about the total number of valence shell electrons present in any molecule.
Limitations of Lewis dot structure:
In the lewis dot structure we displayed electron as a result of total locate to any atom as occur in ionic bonds or as sharing between two atoms as occur in covalent bond, but these two are not only conditions of the bond formation.By this structure we will not estimate the shape of the given molecule.Type of attraction force is also not deterimed through this.It also fails to explain the resonance structure of molecules.Hence limitations of Lewis dot structure is discussed above.
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How many milliliters of milk are in a 1.000-
gallon jug?
Answer:
3.785e+6
Explanation:
Express the number 0.000746 in scientific notation.
A) 746 x 10-6
B) 7.46 x 102
C) 7.46 x 104
D) 7.46 x 104
E) 0.746 x 10-3
Answer: 7.46 x 10-4
Explanation:You move the decimal place 4 times. For any scientific notation question in the future, look at the answer choices and beside the answer choices work it out. By working it out just take the rounded number (which in this case is 7.46) and go to the decimal and move it however many times it states in the 10 (10-4, move 4).
A balloon is filled to a volume of 1.6 L at 278 K. The balloon is left outside overnight and the temperature has dropped to 253 K. What is the new volume?
Explanation:
Charles' law gives the relationship between the volume and the temperature of the gas. Mathematically,
Volume ∝ Temperature
i.e. [tex]\dfrac{V_1}{V_2}=\dfrac{T_1}{T_2}[/tex]
We have, V₁ = 1.6 L, T₁ = 278 K, T₂ = 253, V₂=?
[tex]V_2=\dfrac{V_1T_2}{T_1}\\\\V_2=\dfrac{1.6\times 253}{278}\\\\V_2=1.45\ L[/tex]
So, the new volume is 1.45 L.
40 000 L + 125 000 L scinetific notation
Hydrogen bonding between water molecules makes them tend to stick together. How does this affect the specific heat (SH) and heat of vaporization (HOV) of water
Answer:
The specific heat and heat of vaporization of water will be very high.
Explanation:
The strength of the hydrogen bonds and the attractions that they create between water molecules makes it much harder for water to increase in temperature.
This is because the bonds need to be broken before the water can vaporize (heat of vaporization) or increase in temperature (specific heat)
Your chemistry lab partner is interested in studying how industrial chemicals can pollute the environment. What type of chemistry would you recommend to your lab partner and which courses should they take in order to study it? Explain your answer.
Answer:
I would recommend them becoming an Analytical Chemist because Analytical Chemists examine and identify various elements and compounds to find out the composition, structure, and nature of substances and they determine the concentration of chemical pollutants in soil, water,and air. I would recommend taking inorganic, organic, analytical, and physical chemistry as well as computer science, physics, and environmental science
convert 104.3 centimeters to millimeters.
Answer:
1043
Explanation:
Convert 104.3 Centimeter to Millimeters (cm to mm) with our conversion calculator and conversion tables. To convert 104.3 cm to mm use direct conversion formula below.
104.3 cm = 1043 mm.
Answer:
1043
Explanation:
Multiply 104.3 by 10
A student is given a mixture of NaCl(s) and NaNO3(s) and is tasked with determining the percent of NaCl in the mixture. The student dissolves 3.613 g of the mixture in 50 mL of DI water. The student then adds excess AgNO3(aq) to precipitate the chloride ion as AgCl(s). The student determines that 2.268 g of AgCl is formed.
Answer:
25.60% of NaCl in the mixture
Explanation:
With the amount of AgCl produced we can now the moles of Cl⁻ = Moles of NaCl. With these moles we can now the mass of NaCl and, as total mass was 3.613g, it is possible to determine mass percent of NaCl in the mixture.
Moles NaCl:
2.268g AgCl * (1mol / 143.32g AgCl) = 0.01582 moles AgCl
Molar mass AgCl 143.32g/mol
0.01582 moles AgCl = Moles Cl⁻ = Moles NaCl
Mass NaCl (Molar mass: 58.44g/mol):
0.01582 moles NaCl * (58.44g / mol) = 0.9248g NaCl in the mixture
Mass percent:
(0.9248g NaCl / 3.613g) * 100 =
25.60% of NaCl in the mixturewhat is burning considered ?
Based on the data provided, do the Super Snail Snacks work? Explain your answer
Answer: No
Explanation: The snacks did not work because the result of the snails either stayed the same, or decreased.
How can matter be classified based on how the atoms are arranged?
Answer: Matter can exist in three different states, solid, liquid, and gas, based on the way the atoms and molecules are arranged inside them. These three states are known as three different states of matter. In solids, atoms or molecules are tightly bound to one another thereby creating a rigid nature.
Scientists in a lab are working with two different samples of the element mercury. They know that the different samples are different isotopes. Which property of the isotopes must be different?
Answer:
the mass number
Explanation:
Isotopes are numerous forms of one single element. In simple terms, atomic weights are different for the isotopes. Isotopes refer to the atoms that have the same number of protons but different neutron numbers. The physical properties of the isotopes vary because these properties also based on mass. These variations can be used to distinguish isotopes of an element from each other by applying methods such as fractional distillation and diffusion.
Answer:
The mass number (D) would be correct.
Explanation:
Water flows over Niagara Falls at the average rate of 2,400,000 kg/s, and the average height of the falls is about 50 m. Knowing that the gravitational potential energy of falling water per second = mass (kg) × height (m) × gravity (9.8 m/s2), what is the power of Niagara Falls? How many 15 W LED light bulbs could it power?
Explanation:
It is given that,
Water flows over Niagara Falls at the average rate of 2,400,000 kg/s
The average height of the falls is 50 m
We need to find the power of Niagara Falls.
The gravitational potential energy of falling water is given by :
P = mgh
Power is rate of doing work i.e.
[tex]P=\dfrac{W}{t}\\\\P=\dfrac{mgh}{t}\\\\P=\dfrac{m}{t}\times gh[/tex]
We have, m/t = 2,400,000 kg/s
So,
[tex]P=2400000\times 9.8\times 50\\\\P=1.176\times 10^9\ W[/tex]
If the number of bulbs are n that could power 15 W LED, the,
[tex]n=\dfrac{1.176\times 10^9}{15}\\\\n=78400000\ \text{bulbs}[/tex]
Describe the walls of Antelope Canyon. · How was Antelope Canyon made? · Why is water vapor invisible? · How is rain formed in desert/canyon?
1. Antelope Canyon was formed by the erosion of Navajo Sandstone.
2. The appearance of water is determined
by the way the water molecules are moving.
3. Moist rising air near the Equator cools and condenses into clouds and, later, rain.
which of the following indicates 4 molecules of water?
Answer:
C
Explanation:
Step 1: Solve
We know water has the formula of H20, if we have more molecules of water we don't touch the subscripts because that would change the substance so we can only add coefficients to the formula
Why did a drop of water need to be added in order to initiate the reaction? Select one: a. because the water is needed to wet the chlorine gas so the reaction could occur b. because the water is needed to cool off the reaction so the flask will not explode c. because the water is needed to wet the sand and keep the reaction safe d. because the water is needed to remove a coating on the surface of the metal. It's not A
Answer:
c
Explanation:
because the water is needed to wet the sand to keep d reaction safe
Is Plutonium an element, compound, solution* or heterogeneous mixture.
Answer:
Its an element.
Explanation:
94 on the periodic table
A/An _______ indicates the ratio of atoms in a molecule.
Answer:
A molecular formula indicates the ratio of atoms in a molecule.
Explanation:
A molecular formula or chemical formula is a representation or indication of the number of atoms in a particular compound or molecule have in a specific specific proportion.
These are represented by the symbols of elements, numbers of atoms present and sometime other symbols. For example in water molecule there is one atom of oxygen and two hydrogen atoms.
Thus, the correct answer is : molecular formula
(10)
Which of the following atoms will not form cation or anion
a. A (Atomic No. 16)
b. B (Atomic No. 17)
CC (Atomic No. 18)
d. D (Atomic No. 19)
Answer:
I think it is b. B (Atomic No. 17)
Describe the best method for separating a mixture of sand, salt, and steel shavings by placing the steps below in the correct order.
Iron is magnetic and the other two not, which means a magnet could be used to attract the iron filings out of the mixture, leaving the salt and sand. Salt is water soluble, while sand is not. This means the two can be mixed in water and stirred. The salt will dissolve and the sand will not.
Answer:
4,3,1,2
Explanation:
just did it on edge :)
Portland cement concrete (PCC) has a density of 150 lb/ft3. How many kilograms of PCC are required to cast a cylindrical column 1.15 m in diameter and 7.8 m in height? (1 kg = 2.205 lb, 1 inch = 2.54 cm)
Answer:
Mass, m = 19466.7 kg
Explanation:
Given that,
Portland cement concrete (PCC) has a density of 150 lb/ft³
We need to find how many kilograms of PCC are required to cast a cylindrical column 1.15 m in diameter and 7.8 m in height.
Since, 1 kg = 2.205 lb
1 lb/ft³ = 16.018 kg/m³
150 lb/ft³ = 2402.77 kg/m³
Density, [tex]d=\dfrac{m}{V}[/tex]
m is mass of PCC in kg and V is volume of cylinder
[tex]m=d\times V[/tex]
[tex]m=d\times \pi r^2 h\\\\m=2402.77\times \pi \times (1.15/2)^2\times 7.8\\\\m=19466.70\ kg[/tex]
So, the mass of PCC required is 19466.7 kg.