Answer:
A-210, n-125
A-207, n-122
A-209, n-124
Explanation:
The mass number is the sum of the number of protons and neutrons in the nucleus of an atom.
Astatine has an atomic number of 85, this is the number of protons in its nucleus. We must subtract the given number of neutrons in each option from the mass number and consider the difference. If the difference between the mass number and number of neutrons is exactly 85, then that option represents one of the isotopes of astatine.
Strontium consists of four isotopes with masses of 84 (abundance 0.50%), 86 (abundance of
9.9%), 87 (abundance of 7.0%), and 88 (abundance of 82.6%).
Calculate the atomic mass of
strontium.
Answer:
M = 87.71 amu
Explanation:
The masses of 4 isotopes of Strontium with abundance is as follows :
84 (abundance 0.50%), 86 (abundance of 9.9%), 87 (abundance of 7.0%), and 88 (abundance of 82.6%). Let M is the atomic mass of Strontium. So,
[tex]M=0.50\%\ \text{of}\ 84+9.9\%\ \text{of}\ 86+7\%\ \text{of}\ 87+82.6\%\ \text{of}\ 88\\\\M=\dfrac{0.5}{100}\times 84+\dfrac{9.9}{100}\times 86+\dfrac{7}{100}\times 87+\dfrac{82.6}{100}\times 88\\\\M=87.71\ \text{amu}[/tex]
So, the atomic mass of Strontium is 87.71 amu.
When an organic molecule loses hydrogen atoms it is said to be:_______.
A) reduced
B) oxidized
C) both oxidized and reduced
D) neither oxidized nor reduced
When a saturated hydrocarbon loss a hydrogen involve an unsaturation it oxidises. Thus, when an organic molecule loses hydrogen atoms it is said to be oxidised.
What is oxidation?Oxidation is the process of loss of electron or loss of hydrogen to change into the higher oxidation state. It can also said that reaction with oxygen is oxidation.
The gain of one or more electrons or hydrogen atoms is called reduction . Reduction make a reactant species in lower oxidation state. The species which is reduced is called reductant and the species which is oxidised is called oxidant.
The group or atom which accepts a hydrogen or electrons from other species and oxidise them is called oxidising agents and the groups which give off their hydrogen or electron to other to reduce them is called reducing agents.
Hence, when an organic molecule loses hydrogen atoms it is said to be oxidised.
To find more on oxidation, refer here:
https://brainly.com/question/9496279
#SPJ5
Which metal ions can be precipitated out of solution as chlorides?a. Ag+, Hg2+, Co2+b. Cu2+, Cd2+, Bi3+ c. Ag+, Hg22+, Pb2+ d. Na+, K+, Mg2+
Answer:
Explanation:
In the qualitative analysis of metal salts , we see that in group I , metal chlorides are precipitated out . It is so because their metal chlorides are insoluble in water .
In this group following metal ions are present
Ag+,
Hg₂²⁺
Pb²⁺
Which energy output objects work with the solar panels?
Answer:
In this simulation, you will be able to “see” several different forms of energy and the changes(transfers) that can occur between them.You are also able to work with a system where you canmanipulate the energy input, observe the process of electrical energy generation and manipulatethe output.Click on the “Energy Systems” tab.We will do all of our work here. Be sure to clickthe “Energy Symbols” box so the different types of energy will be visible throughout the process
We have that for the Question "Which energy output objects work with the solar panels" it can be said that the energy output object that works with the solar panels is the
Inverter
From the question we are told
Which energy output objects work with the solar panels?
Generally
Inverter
A Inverter is a device used in a solar installation system,with its primary work being conversion from DC(Direct current) to AC(Alternating Current)
When the panel traps solar energy using photoelectric cells and transfers them to the Inverter converts the DC charge to AC in order to charge the batteryTherefore
the energy output object that works with the solar panels is the
Inverter
For more information on this visit
https://brainly.com/question/12534911?referrer=searchResults
What are the boiling points and freezing points (in oC) of a solution of 50.3 g of I2 in 350 g of chloroform? The kb = 3.63 oC/m, the kf = 4.70 oC/m for CHCl3, and the molar mass of I2 is 253.8 g/mol. The normal boiling point for CHCl3 is 61.2 oC, and the normal freezing point for CHCl3 is -63.5 oC.
Answer:
Boiling point: 63.3°C
Freezing point: -66.2°C.
Explanation:
The boiling point of a solution increases regard to boiling point of the pure solvent. In the same way, freezing point decreases regard to pure solvent. The equations are:
Boiling point increasing:
ΔT = kb*m*i
Freezing point depression:
ΔT = kf*m*i
ΔT are the °C that change boiling or freezing point.
m is molality of the solution (moles / kg)
And i is Van't Hoff factor (1 for I₂ in chloroform)
Molality of 50.3g of I₂ in 350g of chloroform is:
50.3g * (1mol / 253.8g) = 0.198 moles in 350g = 0.350kg:
0.198 moles / 0.350kg = 0.566m
Replacing:
Boiling point:
ΔT = kb*m*i
ΔT = 3.63°C/m*0.566m*1
ΔT = 2.1°C
As boiling point of pure substance is 61.2°C, boiling point of the solution is:
61.2°C + 2.1°C = 63.3°C
Freezing point:
ΔT = kf*m*i
ΔT = 4.70°C/m*0.566m*1
ΔT = 2.7°C
As freezing point is -63.5°C, the freezing point of the solution is:
-63.5°C - 2.7°C = -66.2°C
A chef is testing out new iron cookware. He knows that iron has a specific heat of
445 J/kg°C. He heats a 2 kg iron skillet on stove for 5 minutes and finds that the
temperature of the iron skillet has increased by 250°C. What change in
temperature will the Chef observe when he heats his 4 kg iron skillet on the same
stove for the same amount of time?
A. An increase of 125°C
B. An increase of 250°C
C. An increase of 325°C
O D. An increase of 445°C
He knows that iron has a specific heat of 445 J/kg°C. He heats a 2 kg iron skillet on stove for 5 minutes and finds that the temperature of the iron skillet has increased by 250°C An increase of 250°C change in temperature will the Chef observe when he heats his 4 kg iron skillet on the same stove for the same amount of time.
What is specific heat ?Specific heat can be defined as the measurable amount of heat needed to increase the temperature of one gram of a substance by one degree Celsius of temperature.
The units of specific heat can be represented as calories or joules per gram per Celsius degree where as 1 calorie per gram per Celsius degree.
Specific heat capacity= Heat quantity/ mass × change in temperature.
Learn more about specific heat, here:
brainly.com/question/15177263
#SPJ2
ITS TALKING ABOUT PHOTOSYNTHESIS
Xylem helps plants deliver water and nutrients to the
entire plant. What human body system is this like?
The the two important transport tissues in plants are xylem and phloem. The human body system which is like xylem is circulatory system.
What is xylem?An important transport tissue which is found in the vascular plants along with the phloem is defined as the xylem. The major role of xylem is to transport all the essential nutrients and water to leaves and stems from the roots.
There are mainly two types of xylem, they are primary and secondary. The xylem which is found during the primary growth of the plant is called the primary xylem and the secondary xylem is found in the plant's secondary growth.
The xylem transport the substances through passive transport which does not need any external energy. The vessel elements present in the xylem are found to be similar to the blood vessels in the human body.
The blood vessels of the circulatory system carries nutrients to all the organs and removes wastes from the organs. The arteries carry blood away from the heart and veins carry blood to the heart.
Thus the blood vessels in the circulatory system is analogous to the Xylem.
To know more about the xylem, visit;
https://brainly.com/question/10662190
#SPJ5
Express a length of 13.63 m in centimeters.
Answer in units of cm.
Answer:
1363cm
Explanation:
1m=100cm
13.63m= 13.63•100cm
13.63m=1363cm
How does the number of valence electrons in atoms of metalloids explain why metalloids are semiconductors?
A.They have one or two valence electrons, so they cannot lose electrons easily.
B.They have one or two valence electrons, so they can lose or gain electrons.
C.They have three to six valence electrons, so they cannot lose electrons easily.
D.They have three to six valence electrons, so they can lose or gain electrons.
sorry its supposed to say physics not chemistry at the top -_-
Answer:
They have three to six valence electrons, so they can lose or gain electrons.
Explanation:
just took the quiz
Metalloids are metal like elements showing intermediate properties of gases and metals. They have three to six valence electrons, so they can lose or gain electrons. That's why they are conducting.
What are metalloids?Metalloids are elements showing properties intermediate to that of metals and non-metals. They are located in the periodic table in between metals and nonmetals.
Metalloids appear as metals. They are shiny and conducting. However, their conductivity is low compared to metals and they are classified as semiconductors and they are all brittle in nature.
Boron, silicon, germanium, arsenic etc. examples of metalloids. They contains three to six valence electrons which can be delocalized or lost from the atoms.
These elements can lose electrons as well they can gain more electrons as per the bonding type. The delocalized valence electrons make them conducting. Hence option D is correct.
To find more about metalloids, refer the link below:
https://brainly.com/question/6422662
#SPJ6
A solute added to a solvent raises the boiling point of the solution because: Select one: a. The solute particles raise the solvent's vapor pressure, thus requiring a higher temperature to cause boiling. b. The temperature to cause boiling must be great enough to boil not only the solvent but also the solute. c. The solute increases the volume of the solution, and an increase in volume requires an increase in the temperature to reach the boiling point (derived from PV
Answer:
See the answer below
Explanation:
The correct answer would be that the solute particles lower the solvent's vapor pressure, thus requiring a higher temperature to cause boiling.
Dissolving a solute particle in a solvent leads to a decrease in the vapor pressure of the solvent above the resulting solution when compared to the pure solvent. The lower the vapor pressure of a liquid, the higher the temperature required for the liquid to boil and vice versa. Hence, a higher temperature would be needed to boil a solvent with dissolved solutes.
What does it mean to be "moderated by water"?
water is watching over you
Answer:
it means the higher the water content in the air, the more moderate (less extreme) the climate is.
Why does density increase with more helium
Answer:
density increases with more helium because of its molar mass
GOLF BALL PROPERTIES 1. Gabriel uses these numbers to find the density of the golf balls. Water has a density of 1.0 g/cm3. Which ball will float? (D = m/V) Ball Mass (g) 22 18 Volume (cm) 20 20 a) Ball A b) Ball B c) Ballc d) Ball D 30 OA 20 20 33
Answer:
ball B
Explanation:
Ball B with a density of 0.9 g/cm³ will float in water.
Option B is the correct answer.
What is density?Density is mass per unit volume.
Its unit is given as g/cm³.
We have,
The density of Ball A.
= 22 g / 20 cm³
= 1.1 g/cm³
The density of Ball B.
= 18 g / 20 cm³
= 0.9 g/cm³
Now,
Since the density of water is 1.0 g/cm³,
The ball that will float is the one with a density of less than 1.0 g/cm³.
Therefore,
Ball B with a density of 0.9 g/cm³ will float in water.
Learn more about density here:
https://brainly.com/question/29775886
#SPJ5
what is the scientific name for the chemical formula know as P2Os
Explanation:
I know only P2O5 = Phosphorus pentoxide
Which is not a compound
A.Sugar
B.Water
C.Gold
D.Silicon dioxide
Answer:
C
Explanation:
thats my guess but im not completely sure
The correct chemical equation for the reaction of sodium bromide and lead nitrate is: _________.
a. NaBr(aq) + Pb(NO3)2aq) ---------->PbBr2ts) + NaNO3(aq)
b. NaBr(aq) + Pb(NO3)2----------> PbBr2(aq) + NaNO3(s)
c. 2 NaBr(aq) + Pb(NO3)2(aq)---------> PbBr2(aq) + NaNO3(s)
d. 2 NaBr(aq) + Pb(NO3)2(aq)---------> PbBr2 + NaNO3(aq)
Answer : The correct chemical equation is:
[tex]2NaBr(aq)+Pb(NO_3)_2(aq)\rightarrow PbBr_2(s)+2NaNO_3(aq)[/tex]
Explanation :
Balanced chemical equation : It is defined as the equation in which the atoms of individual elements present of reactant side must be equal to the product side.
According to the question, when sodium bromide reacts with lead nitrate then it reacts to give sodium nitrate and lead bromide as a products.
The balanced chemical equation will be:
[tex]2NaBr(aq)+Pb(NO_3)_2(aq)\rightarrow PbBr_2(s)+2NaNO_3(aq)[/tex]
How did the US government change its policy toward Native American land during the 1850s?
They began to designate all land on the Great Plains as reservation land
They created new treaties and reservations that defined specific boundaries for each tribe
They began to allow Native Americans to hunt on their traditional lands
The started forbidding settlers from claiming any land on the Great Plains
Reduced grazing lands
• Hunting for sport and
Answer:
The correct answer is B) They created new treaties and reservations that defined specific boundaries for each tribe
Explanation:
One of such acts which was used to reallocate the Native American Land was the General Allotment (Dawes) Act of 1887.
It gave permission to the Federal Government to modify the size and ownership structure of land belonging to the Native Americans. The end result was that the total amount of land originally belonging to the Native Americans reduced drastically over the next 500 years.
Cheers!
Q2. The table gives the composition of three particles.
number of
number
of
number of
electrons
particle
neutrons
protons
A
15
15
16
B
15
18
16
A
с
15
15
17
(a) What is the evidence in the table for each of the following?
Particle A is an atom.
[1]
R.A.
Answer:
The proton and electrons are equal,
15protons and 15electrons
Explanation:
An atom is the smallest electrical neutral particle of an element so it means that every atom have same number of protons and electrons.
Atom A has five protons, four neutrons, and five electrons. Atom
B has five protons, six neutrons, and five electrons.
Are atoms A and B isotopes of the same element? Explain how
you know.
SELECT AN ANSWER
They are of the same element because
they have a different number of neutrons.
They are of the same element because
they have the same number of protons and
electrons, but a different number of
neutrons.
They are of the same element because
they have the same number of protons and
neutrons, but a different number of
electrons.
They are of the same element because
they have the same number of protons.
SUBMIT
Answer:
they are the same element because they have the same number of protons and electrons,but a different number of neutrons
1. The process of photosynthesis requires a source of carbon dioxide.
HYPOTHESIS: Increasing the concentration of carbon dioxide available to aquatic plants will increase
the rate of photosynthesis, as measured by the number of oxygen bubbles produced.
Independent variable:
Dependent variable:
Answer:
The rate of photosynthesis is the dependent and concentration of carbon dioxide is the independent
Explanation: The rate of photosynthesis depends on how much carbon dioxide is being supplied which makes it the dependent variable.
Hope this helped! :)
Scientific notation for 782,000 g
Answer:
7.82*10^5
Explanation:
In scientific notation, there is only one number before the decimal and two numbers after, anything after that is counted towards the exponent next to the 10.
Because you move the decimal to the left 5 times to get one number before the decimal (7) your exponent is 5
Hope this helped,
-Kiddoo :)
Are all molecules of a particular substance alike?
Answer:
Yes.
Explanation:
Yes, all molecules of a particular substance are similar or alike if the substance has similar shape and structure. Molecule is made up of two or more atoms having no charge on them and the atoms present in it make bonds with each other. For example, water is made of similar molecules i. e. two hydrogen atom and one oxygen atom bonded together with a covalent bond.
Hydrogen gas, H2, reacts explosively with gaseous chlorine, Cl2, to form hydrogen chloride, HCl(g). What is the enthalpy change for the reaction of 2 mole of H2(g) with 2 mole of Cl2(g) if both the reactants and products are at standard state conditions? The standard enthalpy of formation of HCl(g) is −92.3 kJ/mol. H2(g)+Cl2(g)→2HCl(g)
Answer:
-184.6 KJ/mole
Explanation:
H2(g) + Cl2(g) ------------> 2HCl(aq)
Δ H0 rxn = Δ H0f products - Δ H0f reactants
= 2×-92.3 - (0 + 0)
= -184.6KJ/mole
H2(g) + Cl2(g) ------------> 2HCl(aq) Δ H0rxn = -184.6KJ/mole
Given :
Hydrogen gas,[tex]H_2[/tex] , reacts explosively with gaseous chlorine, [tex]Cl_2[/tex], to form hydrogen chloride, HCl(g).
The standard enthalpy of formation of HCl(g) is −92.3 kJ/mol.
[tex]H_2(g)+Cl_2(g) - >2HCl(g)[/tex]
To Find :
The enthalpy change for the reaction of 2 mole of [tex]H_2(g)[/tex] with 2 mole of [tex]Cl_2(g)[/tex] if both the reactants and products are at standard state conditions .
Solution :
We know ,
[tex]\Delta H^o_{rxn}=\Delta H^{o}f_{products}-\Delta H^of_{reactants}\\\\\Delta H^o_{rxn}=2\times (-92.3)-(0+0)\\\\\Delta H^o_{rxn}=-184.6\ kJ/mol[/tex]
( Since , [tex]H_2[/tex] and [tex]Cl_2[/tex] are their most elementary form . So their enthalpy of formation is 0 kJ )
Therefore , the enthalpy change for the reaction of 2 mole of [tex]H_2(g)[/tex] with 2 mole of [tex]Cl_2(g)[/tex] if both the reactants and products are at standard state conditions is -184.6 kJ/mol .
Hence , this is the required solution .
what is flowering plant
a plant that has flowers and fruits
Which of the following is a chemical property of paper? (4A)
Paper will float on water.
Paper absorbs pen ink.
Paper is white.
Paper will burn.
Answer:
D.) Paper will burn
Explanation:
The first three are physical properties of paper, but the last one is a chemical property of paper
Marcos and Helen study the electron configurations of neutral atoms. They draw the
atomic models shown. Due to their electron structure, what do the two atoms have in
common?
a. period
b. No answer text provided.
c. group
d. mass number
e. atomic number
To see the number of atoms of an element in a given molecule we need to multiply stoichiometry to the number that is written on the foot of the element that is stoichiometry. The correct option is option C.
What is atom?Atom is the smallest particle of any element, molecule or compound. Atom can not be further divided. Atoms contains nucleus in its center and electron that revolve around the atom in fixed orbit.
In the nucleus, proton and neutron are present. Electron has -1 charge while proton has +1 charge. Neutron is neutral that is it has no charge. So overall the charge of nucleus is due to only proton, not by neutron.
In the two figure the number of electrons in the outermost shell or valence shell is 2. The group of periodic table that has valency 2, is the alkaline earth metals. So, the group number, the two atoms have in common.
Therefore, the correct option is option C.
To know more about atom, here:
https://brainly.com/question/13518322
#SPJ2
Part 1: Cats falling out of windows
Answer:
A cat that falls out of the window even if it seems to be doing well, must urgently go to a veterinary clinic in order to be placed under surveillance for at least 24 to 72 hours
Explanation:
What is the composition of nucleotide?
a) a sugar + a phosphate
b) a base + a sugar
c) a base + a phosphate
d) a base + a sugar + phosphate
Answer:
I'm not sure about this question but I think it C
Suppose you place a hot pack into a vacuum chamber and the hot pack caused the temperature to rise from 21 degrees to 23 degrees Celsius. If the
pressure was initially 1 atmosphere, what equation would you use to determine the new pressure at the new temperature? Assume volume, and quantity of
gas are held constant.
Select one:
a. P1/T1 = P2/T2
b. P1V1 = P2V2
c. P1T1 = P2T2
d. P1n1 = P2N2
Answer:
A
Explanation:
Pressure and Temperature have to be divided by each each other because they are directly related.
The Skeletal System does all of the following except:
Produces Blood Cells
Protects Organs
Stores calcium and minerals
Excretes Waste
The skeletal system does not excrete waste. Therefore, option D is correct.
What is the skeletal system ?The skeletal system is our body's central framework. It is also known as the musculoskeletal system. The skeletal system consists of bones and tendons, and ligaments, connective tissue, including cartilage.
The skeletal system plays an important role in support and protection for the body's internal organs and gives the muscles a point of attachment.
Our circulatory system delivers oxygen-rich blood to your bones. Our skeletal system is depend on our urinary system to remove waste produced by bone cells. The bones of your skeleton create a structure that protects our urinary bladder. Our circulatory system delivers oxygen-rich blood to your bones.
Thus, option D is correct.
To learn more about the skeletal system, follow the link;
https://brainly.com/question/1283837
#SPJ2
