Answer:
Measuring distances to stars through stellar parallax. Measuring distances to stars through the moving cluster method. Astronomers measure the temperature of a star by looking at the star's color and its spectrum. The apparent brightness of a star tells how bright it seems to us
Explanation:
Answer:
Analyze the Characteristics of a Star
Explanation:
Surface Temperature
First, you want to determine the color of the star - this can determine the heat and age of the star.
Second, you want to measure the spectrum and get the spectral type.
Chemical Composition
Determine which lines are present in the spectrum.
Luminosity
Measure the apparent brightness and compensate for distance
Radical Velocity
Measure the Doppler shift in the spectrum.
Rotation
Measure the width of spectral lines.
Mass
Measure the period and radial velocity curves of spectroscopic binary stars.
Diameter
1. Measure the way a star’s light is blocked by the Moon.
2. Measure the light curves and Doppler shifts for eclipsing binary stars.
How many atoms are present in 1.8 mol of Ca? Also, how many moles are in 3.4 * 10²⁶ molecules of H2O?
Answer: is this what your looking for?
Explanation: One mole of anything, no matter what the element is, is Avogadro's number, which is 6.02 * 10^23 atoms.
One mole of Calcium is equal to it's atomic weight in grams :
1 mole Ca = 40.08 g = 6.02 * 10^23 atoms
There is a 1000mg in a gram. 1000mg * 40.08g =
=40,080mg of Ca per mole
If you have 8.6mg of Ca that is 8.6mg / 40,080mg = .00021457 of a mole of calcium
so just multiply that by Avogadro's number to give you number of atoms:
.00021457 * 6.02 * 10^23 atoms = 1.292 * 10^20 atoms of Ca
A mole is the amount (10) of material containing [tex]6.02214 * 10^{23}[/tex] particles.
1 mol = [tex]6.02214 * 10^{23}[/tex] particles. This number is also called Avogadro's number
One mole of Calcium is equal to it's atomic weight in grams :
[tex]\text{1 mole Ca} = 40.08 g = 6.02 * 10^{23} \text{ atoms}[/tex]
a) 1g=1000mg
[tex]1000\text{ mg} * 40.08g = 40,080 \text{ mg of Ca per mole}[/tex]
If you have 8.6mg of Ca that is
[tex]\frac{8.6mg}{40,080mg} =0 .00021457 \text{ mole of Ca}[/tex]
In terms of Avogadro number:
[tex]0.00021457 * 6.02 * 10^{23} atoms = 1.292 * 10^{20} \text{ atoms of Ca}[/tex]
b) The number of moles of H₂O will be:
[tex]3.4*10^{26}*6.022*10^{23}\\\\20.47*10^{49} \text{moles}[/tex]
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What volume (in liters, at 253 K and 6.54 atm) of chlorine gas is required to react with 7.89 g of P? 2P(s) + 5Cl2(g) → 5PCl5(s)
Answer:
7.89 grams of phosphorus reacts with 45.15 grams of chlorine
Explanation:
For reacting with 2 mole of P react with 5 mole of Cl2 gas
Molecular weight of phosphorus = 30.97
Molecular weight of 2 mole of phosphorus = 2 * 30.97 = 61.94 grams
Molecular weight of Chlorine molecule = 70.9 grams
Weight of 5 moles of Chlorine molecule = 5 * 70.9 grams = 354.5 grams
61.94 grams of phosphorus reacts with 354.5 grams of chlorine
7.89 grams of phosphorus reacts with 354.5/61.94 * 7.89 grams of chlorine
7.89 grams of phosphorus reacts with 45.15 grams of chlorine
This gland of the endocrine and digestive systems produces insulin to help control the body's sugar levels and enzymes which aid in digestion.
Answer:
Pancreas.
Explanation:
Living systems are self-organized life forms and are known to be very much interactive with their surroundings or environment. Also, living systems are dependent on the flow of information, matter and energy at various levels.
Some examples of living systems in organisms are respiratory system, nervous system, digestive system, and circulatory system.
Additionally, living systems comprises of the following components; cells, organs, muscle, tissues, blood, etc.
An endocrine system refers to a series of ductless glands and organs responsible for the production and secretion of hormones that are used by the body for the performance of various functions such as metabolism, controlling growth, reproduction, mood, sleep, etc. These hormones are secreted directly into the circulatory system (blood) and then transported to the organs and tissues in the body.
Pancreas is one of the glands of the endocrine and digestive systems that produces insulin to help control the body's sugar levels and enzymes which aid in digestion.
Question is in the photo
Answer:
c?
Explanation:
A student adds 5400.0mL of 0.15M NaOH to 201.2mL of 4.0M NaOH. What is the final [NaOH]?
Answer:
0.287 M
Explanation:
Multiply the concentration of each solution by the volume of each (in liters) to get the moles of NaOH in that solution.
0.15 M • 5.4000 L = 0.81 mol NaOH
4.0 M • 0.2012 L = 0.80 mol NaOH
Add the mol of NaOH together to get the total --> 0.81 + 0.80 = 1.61 mol NaOH
Divide by the total volume of solution (5400.0 mL + 201.2 mL = 5,601.2 mL = 5.6012 L)
1.61 mol / 5.6012 L = 0.287 M NaOH
please help me do it dont worry the answers are their just put them in theright place
What is happening when an oxygen molecule is formed from two separate oxygen atoms?
1.Si dos átomos tienen el mismo "Z" pero diferente "A" se trata de : a) Nucleones b) Isótopos c) Mesones
Answer:
Si dos átomos tienen el mismo "Z" pero diferente "A" se trata de Isótopos.
Explanation:
Cada elemento químico se caracteriza por el número de protones de su núcleo, que se denomina número atómico Z. Pero en el núcleo de cada elemento también es posible encontrar neutrones, cuyo número puede variar. La masa atómica (A) se obtiene sumando el número de protones y de neutrones de un núcleo determinado.
Un mismo elemento químico puede estar constituido por átomos diferentes, es decir, sus números atómicos son iguales, pero el número másico es distinto. Estos átomos se denominan isótopos del elemento. Si a un átomo se le añade un neutrón, se convierte en un isótopo de ese elemento químico. En otras palabras, se denomina isótopos a los átomos de un mismo elemento, cuyos núcleos tienen una cantidad diferente de neutrones.
Los isótopos de un elemento tienen las mismas propiedades químicas, pero difieren algo en sus propiedades físicas.
Entonces, si dos átomos tienen el mismo "Z" pero diferente "A" se trata de Isótopos.
Construct an explanation for why the physical properties of the inner core, outer core, and lower mantle are essential for the development of Earth's magnetic field.
Answer:
The hot temperature of inner core and outer core is responsible for the production of magnetic field.
Explanation:
The physical properties of the inner core, outer core, and lower mantle are essential for the development of Earth's magnetic field because the very high temperature of inner core is responsible for the formation of magnetic field. If the inner core is not very hot so the magnetic field will not be generated and our earth's atmosphere will not be save from the solar wind. It can be blown away by the solar wind if this magnetic field is not present so we can conclude that the physical properties of inner core and outer core is important for the production of magnetic field.
Can someone help me out with these chemistry balancing equations questions?
Answer:
C4H6O3 + H2O → 2C2H4O2
C2H4 + 3O2 → 2CO2 + 2H2O
2C4H10 + 13O2 → 8CO2 + 10(H2O)
Explanation:
if i want to make 14 moles of potassium chloride, how many grams of potassium do i need? Show all work. Make sure to include unit and substance
Answer:
The answer is 0.013413582325191. i assume you are converting between moles Potassium Chloride and gram. The molecular formula for Potassium Chloride is KCl. The SI base unit for amount of substance is the mole. 1 mole is equal to 1 moles Potassium Chloride, or 74.5513 grams.
Explanation:
I also really need help on this one.
Answer:
I would say ether the first one or the third one because on those questions you always want to choose the one that gives the most information or sound more believe
Hope this helped
What is the most general name for any single type of matter that is made from a specific arrangement of atoms?
A.
substance
B.
solid
C.
molecule
D.
element
Answer:
The answer is C. substance
Explanation:
I did this on study island and got it right, hope you enjoy.
Exothermic reactions have _____ net bond energy.
A) positive
B) negative
C) neutral
Please help me ........
!!!PLEASE HELP!!!!
What is the molarity of a solution with 0.5 moles of potassium fluoride dissolved to make 50 mL of solution?
A.0.1 mol/L
B.10 mol/L
C.1.72 mol/L
D.1450 mol/L
Answer: B
Explanation: molarity = concentration c= n/V = 0.5 mol/ 0.05 l = 10 mol/l
The molarity of a solution is the number of moles of its solute divided by volume in liters. The molarity of the 50 ml solution containing 0.5 moles of potassium fluoride is 10 M or 10 molar.
What is molarity ?Molarity is a common term used to express the concentration of a solution. It is the ratio of number of moles of solute particles to the volume of solution in liters. Hence, its unit is mol/L or molar.
The molarity of a solution is a colligative quantity as well as temperature dependent.
Given,
no.of moles of potassium fluoride salt in water = 0.5 moles.
volume of solution = 50 ml
1 L = 1000 ml
then 50 ml = 0.05 L.
Molarity = no.of moles of solute/ volume of solution in L
M = 0.5 moles/ 0.05 L
= 10 M.
Therefore, the molarity of the given solution is 10 molar.
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The natural pH of rain water is
acidic
neutral
basic
Please help
Answer:
between 5.0 and 5.5
Explanation:
acidic
Read the sentence from "Black Hole Beginnings."
As more stuff gathers, its combined gravitation grows stronger.
What question should readers ask to determine the effect in the sentence?
How much stuff is combined?
Where does the stuff gather?
Why does the gravitation grow stronger?
What happens when more stuff gathers?
Answer: the answer Is d
Explanation:
The question that readers should ask to determine the effect in the sentence is that what happens when more stuff gathers?
What is a sentence?Sentence is defined as a group of words, usually containing a subject and a verb, expressing a statement, question, instruction, or exclamation, and, when written, starting with a capital letter and ending with a period or other mark, example, Your sentences are too long and complicated.Many sentences written together form a paragraph.
In law, a punishment is which is given by a law court to a person or organization that is guilty of a crime. It is a grammatical unit of one or more words that expresses an independent statement, question, request, command, exclamation, etc.
In print or writing, a sentence typically begins with a capital letter and ends with appropriate punctuation; in speech it displays recognizable, communicative intonation patterns and is often marked by preceding and following pauses.
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What fossil helped support Wegener's hypothesis of continental drift?
A. Gondwanaland
B. Kannemeyerid
C. Mesosaurus
D. Glossopteris
Answer:
Glossopteris
Explanation:
Glossopteris is a fossil fern that helped support Wegener's hypothesis.
Hope this helps! Have a great day!
_____________ is the force or pressure of electricity and is compared to the amount of water pressure in a hose.
Answer:
Voltage.
Explanation:
Voltage is the force or pressure of electricity and is compared to the amount of water pressure in a hose.
Answer:
Voltage is the force or pressure of electricity and is compared to the amount of water pressure in a hose.
which reacts faster, rock salt or grains of salt? Why?
Answer:
salt
Explanation:
because it has a much larger volume ratio
A gas occupies 10.2 L at 0.986 atm. What is the pressure if the volume increases to 16.0 L?
Answer:
0.629 atm
Explanation:
P1V1 = P2V2
P1 = 0.986 atm
V1 = 10.2 L
P2 = ?
V2 = 16.0 L
Solve for P2 --> P2 = P1V1/V2
P2 = (0.986 atm)(10.2 L) / (16.0 L) = 0.629 atm
I NEED THIS ASAP
A truck was carrying a substance in a tank. The molecules of that substance were moving away from each other. The truck parked overnight in a place where energy transferred out of the substance. In the morning, the substance was a gas. How were the molecules moving in the morning? Explain why the molecules were moving that way after energy was transferred out of them.
Answer:
1. In the morning the molecules were moving away from each other with a smaller speed than when the truck was carrying the substance.
2. The reason is that the molecules contain less average kinetic energy, thus their average speed is lower.
Explanation:
Our model of the state (phases) of the substances describes the molecules of solids as not moving away from each other, they are relatively fixed with respect to each other, just vibrating; the molecules of liquids as free to slide pass each other, which permits they to flow, but not moving away from each other; and the the molecules of the gases as moving away from each other, which is the cause of them occupying the whole space of the container that holds them.
According to that, the substance that the truck was carryng was a gas, because the molecules were moving away from each other.
After parking overnight, where energy transferred out of the substance, in the morning, the substance was a gas. Hence, the molecules were moving away from each other too. This answer the first question.
Since energy was transferred out of the substance, in the morning the temperature of the substance decreased (but no enough to make it a liquid). The average kinetic energy of the gases depends only on the temperature. So, the average kinetic energy of the molecules in the morning was smaller than when the truck was carrying the substance. Since the kinetic energy is proportional to the square of the speed of the molecules, the smaller average kinetic energy means that the average speed of the molecules was smaller too. Hence, in the morning the molecules were moving away from each other with a lower speed than when the truck was carrying the substance.
Average kinetic energy is the average sum of all kinetic energy of all the molecules of gases. Therefore, molecules will move at a lesser speed as average kinetic energy will become small.
What is kinetic energy?It is a energy which is possess by a moving object. It is very difficult to find the correct value of kinetic energy so we find average kinetic energy. Which is very easy to calculate as compared to calculating kinetic energy. It is not dependent on the type of gases or mass of gases.
Mathematically, the formula for kinetic energy can be given as
K.E=1/2mv²
Where,
m= mass of object
v= velocity of object
Molecules will move at a lesser speed as average kinetic energy will become small.
Therefore, molecules will move at a lesser speed as average kinetic energy will become small.
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Which part of an atom has most of its mass?
А. electrons
B.neutrons
c.nucleus
D.protons
Answer:
B
Explanation:
Which three of the following are the laws that Mendel discovered?
Law of Heredity
The Law of Segregation
The Law of Dominance
Law of Gravity
The Law of Independent Assortment
Answer:
genetics i.e the law of heredity
Answer:Mendel proposed three laws: Law of Dominance. The Law of Segregation. Law of independent assortment.
Explanation:Gregor Johann Mendel was a scientist who is recognized as the Father and Founder of genetics. Mendel conducted many experiments on the pea plant (Pisum sativum) between 1856 and 1863. He studied the results of the experiments and deducted many observations. Thus, laws of inheritance or Mendel’s laws of inheritance came into existence. Before learning about Mendel’s laws of inheritance, it is important to understand what the experiments performed by Mendel were.
What is the pow of a solution that has a hydroxide ion concentration of 4.82 x 10-6 M?
Answer:
pOH = 5.32
Explanation:
What is the pOH...
The pOH of a solution is defined as:
-log [OH⁻] The -log of hydroxide ion concentration in molarity units
It is used to find pH of a solution because: pH = 14-pOH
Thus, the pOH of the solution of the problem is:
pOH = -log [OH⁻] = -log [4.82x10⁻⁶M]
pOH = 5.32
How many moles are present in 5.24g of H2O?
Answer:
The answer is 18.01528.
We assume you are converting between grams H2O and mole.
Explanation:
Which gas law would apply to the following scenario.
A family is going to a party in the mountains (no change in temperature). It was their job to bring balloons. By the time they arrived 2 of the balloons had
popped,
Gay-Lussac's Law
Boyle's Law
Charles Law
Avogadro's Law
C + 2ZnO → CO2 + 2zn
How many grams of
carbon dioxide will be
produced if 135 grams
of ZnO is completely
reacted?
Answer:
36.5 g CO2
Explanation:
First, Write a Balanced Equation
C + 2 ZnO → CO2 + 2 Zn
Useful Information,
MW of ZnO = 81.41 g
MW of CO2 = 44.01 g
135 g ZnO x (1 mol ZnO / 81.41 g ZnO) x (1 mol CO2/2 mol ZnO) x ( 44.01 g CO2 / 1 mol CO2 ) = 36.5 g CO2
What is the pH of a solution that has [H+] of .0042M?
Answer:
pH = 2.4
Explanation:
pH is defined as the negative log of the hydronium concentration.
Thus, we can plug in the given hydronium concentration:
pH = -log[H⁺] = -log[0.0042] = 2.4 (two significant figures)
The pH of the solution is 2.4.
P.S: Although I referred to [H⁺] as hydronium concentration, it is more accurate to express it as [H₃O⁺], though they are interchangeable and means the same thing.