There are________
neutrons in the stable isotope of rhenium (Re-
185)
A.134
B.90
C.125
D.110
There are 110 neutrons in the stable isotope of rhenium. The correct option is D.
What are neutrons?A neutron is a subatomic particle that exists in the nucleus of all atoms except simple hydrogen. The name of the particle comes from the fact that it has no electrical charge; it is neutral. Neutrons have a very high density.
With the exception of the single-proton hydrogen nucleus, nuclei require neutrons to be stable. Neutrons are abundantly produced during nuclear fission and fusion.
Through mainly the process of fission, fusion, as well as neutron capture processes, they are a major contributor to the nucleosynthesis of chemical elements within stars.
The element rhenium-185 is made up of 75 protons, 110 neutrons, and 75 electrons. The element rhenium-187 is made up of 75 protons, 112 neutrons, and 75 electrons.
Thus, the correct option is D.
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how many atoms are in 2 miles of h2o
Answer:
one mole of water contains 6.02 x 1023 MOLECULES of water.
But each molecule of water contains 2 H and 1 O atom = 3 atoms, so there are approximately 1.8 x 1024 atoms in a mole of water.
Explanation:
hope it helps you paigegeorge
Which of the following is considered an ionic solid? a) (NH4)2CO3 b) CBr4 c) SeBr2 d) XeF4 e) None of the above is an ionic solid.
Answer: NH4)2CO3
Explanation:
Ionic solids are the solids that are simply held together by ionic bonds. Ionic bonds are lattices that are typically made up of oppositely charged ions and they usually possess a high melting point.
An example of ionic bond is NH₄)₂CO₃ which is referred to as Ammonium carbonate. This is a salt and it readily degrades upon heating to carbon dioxide and gaseous ammonia.
The flask contains 10.0 mL of HCl and a few drops of phenolphthalein indicator. The buret contains 0.160 M NaOH. It requires 18.2 mL of the NaOH solution to reach the end point of the titration. A buret filled with a titrant is held above a graduated cylinder containing an analyte solution. What is the initial concentration of HCl
Answer:
Approximately [tex]0.291\; \rm M[/tex] (rounded to two significant figures.)
Explanation:
The unit of concentration [tex]\rm M[/tex] is the same as [tex]\rm mol \cdot L^{-1}[/tex] (moles per liter.) On the other hand, the volume of both the [tex]\rm NaOH[/tex] solution and the original [tex]\rm HCl[/tex] solution here are in milliliters. Convert these two volumes to liters:
[tex]V(\mathrm{NaOH}) = 18.2\; \rm mL = 18.2 \times 10^{-3}\; \rm L = 0.0182\; \rm L[/tex].[tex]V(\text{$\mathrm{HCl}$, original}) = 10.0\; \rm mL = 10.0\times 10^{-3}\; \rm L = 0.0100\; \rm L[/tex].Calculate the number of moles of [tex]\rm NaOH[/tex] in that [tex]0.0182\; \rm L[/tex] of [tex]0.160\; \rm M[/tex] solution:
[tex]\begin{aligned} n(\mathrm{NaOH}) &= c(\mathrm{NaOH})\cdot V(\mathrm{NaOH})\\ &= 0.160\; \rm mol \cdot L^{-1} \times 0.0182\; \rm L \approx 0.00291\; \rm mol\end{aligned}[/tex].
[tex]\rm HCl[/tex] reacts with [tex]\rm NaOH[/tex] at a one-to-one ratio:
[tex]\rm HCl\; (aq) + NaOH\; (aq) \to NaCl\; (aq) + H_2O\; (l)[/tex].
Coefficient ratio:
[tex]\displaystyle \frac{n(\mathrm{HCl})}{n(\mathrm{NaOH})} = 1[/tex].
In other words, one mole of [tex]\rm NaOH[/tex] would neutralize exactly one mole of [tex]\rm HCl[/tex]. In this titration, [tex]0.291\; \rm mol[/tex] of [tex]\rm NaOH\![/tex] was required. Therefore, the same amount of [tex]\rm HC[/tex] should be present in the original solution:
[tex]\begin{aligned}&n(\text{$\mathrm{HCl}$, original})\\ &= n(\mathrm{NaOH})\cdot \frac{n(\mathrm{HCl})}{n(\mathrm{NaOH})} \\ &\approx 0.00291\; \rm mol \times 1 = 0.00291\; \rm mol\end{aligned}[/tex].
Calculate the concentration of the original [tex]\rm HCl[/tex] solution:
[tex]\displaystyle c(\text{$\mathrm{HCl}$, original}) = \frac{n(\text{$\mathrm{HCl}$, original})}{V(\text{$\mathrm{HCl}$, original})} \approx \frac{0.00291\; \rm mol}{0.0100\; \rm L} \approx 0.291\; \rm M[/tex].
A cannonball made of iron has a volume of 110. cm3. What is the mass, in kilograms, of the cannonball?
Answer:
1 cubic centimeter (cu cm) = 0.001 kilogram (kg)
110cm³ =110*0.001=0.11kg
Explanation:
The volume has been the space occupied by the object and substances and uses the derived units. The mass of the iron ball with a volume of 110 cubic centimeters is 0.11kg.
What is volume?
Volume has been the three-dimensional space that an object has been using in space. The volume can be measured differently for the various states of matter in various units. Volume is the physical parameter to measure the states of matter.
The estimation of the volume can be given by density or mass and has been expressed by the various units like liters, milliliters, cubic meters, cubic centimeters, kiloliters, cubic decimeters, gallons, etc.
The unit cubic centimeter can be converted into kilogram (kg) as:
1 cubic centimeter = 0.001 kilogram
Given,
The volume of a cannonball made of iron = 110 cubic centimeters
The unit conversion from cubic centimeter to kg is shown as:
1 cubic centimeter = 0.001 kg
110 cubic centimeters = 0.11 Kg
Therefore, 0.11 kilogram is the mass of a cannonball made of iron.
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What determines the shape and function of a protein?
The shape and function of a protein are primarily determined by its three-dimensional structure, which is a result of its primary, secondary, tertiary, and quaternary structures.
Primary Structure: The primary structure of a protein is the linear sequence of amino acids that make up the polypeptide chain. The sequence is dictated by the genetic information encoded in the DNA of the gene that corresponds to the protein. Each amino acid in the sequence is represented by a specific codon in the DNA, and this sequence of amino acids forms the backbone of the protein.
Secondary Structure: The secondary structure refers to the local spatial arrangement of the polypeptide backbone, which is stabilized by hydrogen bonds between amino acids. The two most common secondary structures are alpha-helices and beta-sheets. These structures are important for the stability and folding of the protein.
Tertiary Structure: The tertiary structure is the three-dimensional folding of the entire polypeptide chain, including the secondary structure elements. Various interactions, such as hydrogen bonds, disulfide bridges, ionic interactions, hydrophobic interactions, and van der Waals forces, play a crucial role in stabilizing the tertiary structure. This folding brings distant parts of the polypeptide chain close together, contributing to the unique shape of the protein.
Quaternary Structure: Some proteins are composed of multiple polypeptide subunits, and the way these subunits come together forms the quaternary structure of the protein. The interactions between the individual subunits contribute to the overall structure and function of the complex protein assembly.
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Which of the following is a buffer system?
A. NaCl and NaNO3
B. H2CO3 and KHCO3
C. HCl and NaOH
D. H2O and HCl
E. NaCl and NaOH
Answer:
B. H2CO3 and KHCO3
Explanation:
The buffer system is a system in which the solution deny for change in the ph level i.e. at the time when the acid is added to it. It can be made either in a weak acid and salt or can be a weak base and its salt. Now when the acid is added to a buffer so the ratio is not impacted due to which it does not change sufficient for pH level
As per the given options, the third one is correct as the H2CO3 denotes a weak acid and the KHCO3 represents the salt. And these two solution does not create any change in the level of pH
Therefore the option B is correct
What is 2.1 x 10^6 + 6.2 x 10^7 in scientific notation
Answer:
2100000 + 62000000
Explanation:
You move the decimal place to the right or left acording to the exponent (right if the exponent in positive, left of the exponent in negative.) Ex: if you're solving for 6.2*10^7 you move the decimal 7 places to the right.
Hope this helped,
-Kiddoo :)
You bought a new car and estimated that your monthly payment would be $312. However, your actual payment amount is $325. How much error was in your estimate?
Oxalic acid, H2C2O4*2H2O (molar mass = 126.07 g/mol) is oftenused as a primary standard for the standardization of a NaOHsolution. If 0.147 g of oxalic acid dihydrate is nutralizedby 23.64mL of a NaOH solution, what is the molar concentration ofthe NAOH solution? Oxalic acid is a diprotic acid. (What is thebalanced equation?)
Answer:
0.09865M of NaOH
Explanation:
As a diprotic acid, 1 mole of oxalic acid reacts with 2 moles of NaOH as follows:
H2C2O4 + 2 NaOH → 2 H2O + Na2C2O4
With the mass of the acid and its molar mass we can obtain the moles of oxalic acid. Twice these moles are the moles of NaOH in the solution. As you required 23.64mL = 0.02364L of the NaOH, you can knkow molarity, thus:
Moles Oxalic acid:
0.147g * (1mol / 126.07g) = 1.166x10⁻³ moles Oxalic acid.
Moles NaOH:
1.166x10⁻³ moles Oxalic acid * (2 moles NaOH / 1 mole H2C2O4) = 2.332x10⁻³ moles NaOH
Molarity:
2.332x10⁻³ moles NaOH / 0.02364L =
0.09865M of NaOHA state of dynamic equilibrium, Ag2CO3(s) 2Ag^+(aq) + CO3^2-, exists in solution.
What shift occurs in the equilibrium if HCl (aq) is added to the system? Explain please
Answer:
The equilibrium will shift to the right producing more Ag⁺ and CO₃²⁻
Explanation:
In the equilibrium:
Ag₂CO₃(s) ⇄ 2Ag⁺(aq) + CO₃²⁻(aq)
The change in concentration of Ag⁺ or CO₃²⁻ will shift the equilibrium
The addition of HCl(aq) (Dissociates in H⁺ and Cl⁻ ions) produce the formation of AgCl. The reaction is:
Ag⁺(aq) + Cl⁻(aq) ⇄ AgCl(s)
That means the addition of HCl decrease concentration of Ag⁺.
Based on LeChatelier's principle: As the Ag⁺ decreases, the equilibrium will decrease amount of Ag₂CO₃ producing more Ag⁺ and CO₃²⁻. That is:
The equilibrium will shift to the right producing more Ag⁺ and CO₃²⁻find the R when p=6000,T=3 yrs 6 month ,I=1155
R= 1155×100/6000×3/12
R= 1155×2/3
R=770E
1
1 point
Which of the following is an elemental substance?
Select all the correct answers.
Mercury
2
Oxygen (O2)
3
Platinum
Chlorine (C12)
Carbon Dioxide (CO2)
Answer:
oxygen and Carbon dioxide
In a compound the elements are _____ together, whereas in a mixture the substances are blended together.
Answer:
bonded
Explanation:
Compounds are two elements bonded together.
A mixture is multiple substances blended together. The substances aren't bonded together and can easily be extracted from each other.
In which of does the convection only occur in
A. Gases
B. Fluids
C. Liquids
D. Solids
Answer:
B. Fluids
I hope this helps!
Answer:
B
Explanation:
Exactly how many -OH groups are found in a 6 carbon alditol?
Answer:
The number of OH group found in found in a 6 carbon alditol is 6
Explanation:
The structure of a 6 carbon alditol is shown on the first uploaded image
Which statement correctly compares an atom of an alkali metal with an atom of the alkaline earth metal next to it on the periodic table? aThe alkali metal atom forms a +1 ion, while the alkaline earth metal atom forms a +2 ion. bThe alkali metal atom forms a +2 ion, while the alkaline earth metal atom forms a +1 ion. cThe alkali metal atom has one less shell of electrons than the atom of the alkaline earth metal. dThe alkali metal atom has one more shell of electrons than the atom of the alkaline earth metal.
The atom of alkaline earth metal has one more proton and one more electron than the alkali metal that is next to it to the left on the periodic table. Then the atomic number of the alkali metal is one unit less than the atomic number of the alkaline earth metal next to it
Answer:
A) The alkali metal atom forms a +1 ion, while the alkaline earth metal atom forms a +2 ion.
Explanation:
Let's evaluate each answer.
A: The alkali metal atom forms a +1 ion, while the alkaline earth metal atom forms a +2 ion.
This means that the alkali metal atom has to lose 1 valence electron to form a +1 ion while the alkaline earth metal atom has to lose 2 valence electrons to form a +2 ion. This is accurate because alkali metal atoms have 1 valence electron while alkaline earth metal atoms have 2, so the statement is correct.
B: The alkali metal atom forms a +2 ion, while the alkaline earth metal atom forms a +1 ion.
This would mean that the alkali metal atom has to lose 2 valence electrons to form a +2 ion, while the alkaline earth metal has to lose 1 valence electron to form a +1 ion. This is incorrect because alkali metal atoms only have 1 valence electron and will become a +1 ion when losing that electron, while alkaline earth metals have 2 valence electrons and will form a +2 ion upon losing them.
C: The alkali metal atom has one less shell of electrons than the atom of the alkaline earth metal.
This would mean that the alkali metal atom would be located one period higher up than the alkaline earth metal atom. This is untrue, because the question states that the alkali metal atom is located directly next to the alkaline earth metal atom, so they have the same amount of electron shells.
D: The alkali metal atom has one more shell of electrons than the atom of the alkaline earth metal.
This would mean that the alkali metal atom would be located one period lower on the periodic table than the alkaline earth metal atom. Similar to the previous statement, this is untrue because the question states that they are located directly next to each other, or on the same period.
(Also, I just took this quiz and e2020 says it's right.)
1
Select the correct answer.
Which statement about the relationship between laws, hypotheses, and theories is true?
A.
Laws that remain true over an extended period of time are considered theories.
B.
A theory that holds true for a long time is considered a law.
C.
If a law is not contradicted after a lot of testing, it may be considered a hypothesis.
D.
If a hypothesis is not contradicted after a lot of testing, it may be considered a law.
Answer:
the answer is D
Explanation:
Over the course of many years, a rural farm town becomes more urban. Which of the following will most likely happen in the town as a result of this urbanization?
Answer:
Explanation:
Rivers may be contaminated by sewage.
I do hope I helped you! :)
Consider a closed container of gas that is a mixture of 30% CO2 and 70% N2 at room temperature 20°C. The gases are in thermal equilibrium with one another. a) Which has the higher kinetic energy, the average CO2 or N2 molecule? b) What is that root-mean-square velocity of a CO2 molecule? For reference, a carbon atom has 6 protons, a nitrogen atom has 7 protons, and an oxygen atom has 8 protons.
Answer:
a. the kinetic energy will be the same.
b. [tex]\mathbf{\overline v = 407.65 \ m/s}[/tex]
Explanation:
The kinetic theory deals with how the arrangement of particles of a substance determines the properties that substance will possess and the state in which it is likely to be found under a given set of conditions. From the postulates of the kinetic theory of gases, The average kinetic energy of the gas molecules is a measure of the temperature of the gas molecules, This implies that the kinetic energy is dependent on the temperature.
i.e
[tex]K.E = \dfrac{3}{2} \ KT[/tex]
where ;
K = Boltzmann Constant
Since the given gases are in thermal equilibrium, therefore, the kinetic energy will be the same.
b).
The root mean square velocity of CO2 molecule is represented by the equation :
[tex]\overline v = \sqrt{\dfrac{3RT}{M_m}}[/tex]
[tex]\overline v = \sqrt{\dfrac{3\times 8.314 \ J/K /mole \times (293.15 \ K ) }{44 \times 10^{-3} \ kg / mol}}[/tex]
[tex]\overline v = \sqrt{\dfrac{7311.7473 }{44 \times 10^{-3} }}[/tex]
[tex]\overline v = \sqrt{166176.075 \ m/s}[/tex]
[tex]\mathbf{\overline v = 407.65 \ m/s}[/tex]
Which statement describes a property that is unique to metalloids?
Metalloids are shiny.
Metalloids are semiconductive.
Metalloids are solid.
Metalloids are brittle.
Answer:
Metalloids are semiconductive.
Explanation:
Answer: Metalloids are semiconductive.
3-An analysis that determines the relative amounts of analytes in numerical terms
A) Quantitative Analysis
B) Qualitative Analysis
C)Quantitative Synthesis
D) Qualitative Synthesis
Q1-(30 Marks) Choose the correct answer
Answer:
A.
Explanation:
Quantitative analysis.
which alkene represents the correct starting material phg?
Explanation:
The pH is larger than 7.
The relationship between pH and pOH is
pH + pOH = 14
if something is base, it's pH is greater than 7.
it's pOH is between 0 and 7.
Decaying plants and animals are important to an ecosystem because they
A.
cause disease in living organisms.
B.
reduce soil erosion.
C.
recycle oxygen to the air.
D.
return nutrients to the soil.
Answer:
The option D is correct answer.
Decaying pants and animals are important to the ecosystem as they return the nutrients to the soil.
What is an ecosystem?Ecosystem is defined as a system which consists of all living organisms and the physical components with which the living beings interact. The abiotic and biotic components are linked to each other through nutrient cycles and flow of energy.
Energy enters the system through the process of photosynthesis .Animals play an important role in transfer of energy as they feed on each other.As a result of this transfer of matter and energy takes place through the system .Living organisms also influence the quantity of biomass present.By decomposition of dead plants and animals by microbes nutrients are released back in to the soil.
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Part Of flowers that contains pollen is
Please answer right
Answer:
its the stamen, it also supports the Anther.
Answer:
The Stamen
Explanation:
The stamen is a slender filament supporting the anther, it is what produces and holds pollen in flowers.
can some one help The function of the cell wall in a plant cell is Question 2 options: Allowing material to pass in and out of the cell Uses carbon dioxide, water and energy from the sun to make sugar Breaks sugar down into ATP which the cell can use for energy Provides support and protection for the cell
Answer:
the protection one
Explanation:
the cell wall acts a barrier
What is an example of a physical change?
A. having less ash than the paper that was burned to form it
B. ice forming and then melting back into water
C. rust having a different identity than the iron it forms on
D. the irreversible reaction of vinegar and baking soda
What one would you guys choose?
Answer:
B is correct answer
Explanation:
Answer:
B.
Explanation:
The density of silver is 10.5 g/cm3. What is the mass (in kilograms) of a cube of silver that measures 0.94 m on each side?
Answer:
8721.132 Kg.
Explanation:
The following data were obtained from the question:
Density (D) of silver = 10.5 g/cm³
Length (L) of silver = 0.94 m
Mass (m) of silver =.?
Next, we shall determine the volume of silver. This can be obtained as follow:
Volume = Length × Length × Length
Volume = L × L × L
Volume = L³
Length (L) of silver = 0.94 m
Volume (V) of silver =?
Volume (V) of silver = 0.94³
Volume (V) of silver = 0.830584 m³
Next, we shall convert 0.830584 m³ to cm³. This can be obtained as follow:
1 m³ = 1×10⁶ cm³
Therefore,
0.830584 m³ = 0.830584 m³ / 1 m³ × 1×10⁶ cm³
0.830584 m³ = 830584 cm³
Therefore, 0.830584 m³ is equivalent 830584 cm³.
Thus, the volume of the silver is 830584 cm³.
Next, we shall determine the mass of the silver. This can be obtained as follow:
Density (D) of silver = 10.5 g/cm³
Volume of the silver = 830584 cm³.
Mass of silver =.?
Density = mass /
10.5 = mass of silver /830584
Cross multiply
Mass of silver = 10.5 × 830584
Mass of silver = 8721132 g
Finally, we shall convert the mass of silver, 8721132 g to kilogram (kg). This can be obtained as follow:
1000 g = 1 Kg
Therefore,
8721132 g = 8721132 g / 1000 g × 1 Kg
8721132 g = 8721.132 Kg
Therefore, the mass of each cube of silver is 8721.132 Kg
PLEASE HELP ME, I HAVE NO IDEA HOW TO DO THIS :(
Lol . same here. If u get any ideas please let me know
Answer:
See the picture you have to write like this
1- Science that deals with the identification and quantification of the components of material systems
A)Analytical Science
B)Biochemistry
C)Organic Chemistry
D) Inorganic Chemistry
Q1-(30 Marks) Choose the correct answer
Answer:
Analytical science
Explanation: