Answer:
2.255 x 10²³ g
Explanation:
Data Given:
no. of molecules of BeO = 5.43 x 10⁴⁵ molecules
mass of BeO = ?
Solution:
first we will find no. of moles
Formula used
no. of moles = no. of molecules / Avogadro's number
Where
Avogadro's number = 6.022 x 10²³
Put values in above equation
no. of moles = 5.43 x 10⁴⁵ molecules / 6.022 x 10²³ (molecules/mol)
no. of moles = 9.02 x 10²¹ mol
So,
There are 9.02 x 10²¹ moles of BeO of 5.43x10⁴⁵
Now we will find the mass
For this formula will be used
No. of moles = Mass in grams/ molar mass
Rearrange the above equation
mass in grams = no. of moles x molar mass . . . . . (1)
molar mass of BeO = 9 + 16 = 25 g/mol
Put values in equation 1
mass in grams = 9.02 x 10²¹ moles x 25 g/mol
mass in grams = 2.255 x 10²³ g
So,
Mass of 5.43 x 10⁴⁵ molecules of BeO = 2.255 x 10²³ g
The mass of 5.43x10^45 molecules of BeO can be calculated using the atomic masses provided in Appendix A.
Explanation:The mass of 5.43x10^45 molecules of BeO can be calculated using the atomic masses provided in Appendix A. The atomic mass of BeO is given by the formula BE = {[2m(^1H) + 2mn] - m(ª X)}c². We can substitute the atomic masses of ^1H (1.007825 u) and mn (1.008665 u) into the formula to calculate the binding energy (BE). By rearranging the formula, we can solve for the mass of 5.43x10^45 molecules of BeO.
Why is milk considered a colloid?
Answer:
Milk is considered a colloid because it is a homogeneous mixture
Explanation:
Milk is a colloid because it's a liquid mixture where solid protein particles, large enough to scatter light, are evenly distributed and do not settle with time. This causes milk, like all colloids, to appear cloudy or opaque.
Explanation:Milk is considered a colloid because it is an example of a liquid mixture in which solid particles, that are large enough to scatter light, are dispersed. This property of colloids is known as the Tyndall effect, and it's the reason why colloids, including milk, may appear cloudy or opaque.
The term 'colloid' originates from the Greek words for 'glue' and 'like' and was first used to designate mixtures similar to milk, which contains small protein particles dispersed throughout the liquid. When milk is dehydrated, it forms powdered milk particles of colloidal size.
In simpler terms, a colloid is a kind of mixture where one substance is evenly distributed within another, and the dispersed particles do not settle with time, just like the molecules in milk.
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Predict the following chemical formula for a compound between Al and S.
AIS
Al2S3
AI3S2
AIS3
Answer: Al2S3
Explanation: The oxidation number of Al is +3 since it is in group 3 ( Al+3).
Sulfur is in group 6 and has an oxidation of -2 since it is a nonmetal and an anion.
Criss cross the charges and write them as subscripts.
So the chemical composition is
Al2S3
how do you determine the theoretical mass of CaCl2
The theoretical mass of [tex]CaCl_2[/tex] is 110.
Explanation:
Mass of one atom of calcium = 40 .
Mass of one atom of chlorine=35.5 .
Hence , two atoms would be [tex]35.5 \times 2=70.[/tex]
Therefore, mass of calcium chloride would be net sum both constituent atoms
= [tex]40+70=110[/tex]
So the theoretical mass of [tex]CaCl_2[/tex] is 110.
The theoretical mass is the measure of item coming about because of an ideal chemical reaction, and in this manner not equivalent to the sum you'll really get from a response in the lab. It is the measure of item coming about because of an ideal chemical reaction, and therefore not equivalent to the sum you'll really get from a response in the lab.
4.81*10^24 atoms of lithium
To find the number of moles in [tex]\(4.81 \times 10^{24}\)[/tex] atoms of LiCl, use Avogadro's constant. The calculation yields approximately 8 moles, indicating the quantity of formula units present in the given number of atoms.
To determine the number of moles in a given quantity of formula units, you can use Avogadro's constant. Avogadro's constant states that one mole of any substance contains approximately [tex]\(6.022 \times 10^{23}\)[/tex] entities (atoms, molecules, or formula units). In this case, the formula unit is LiCl.
Given that there are [tex]\(4.81 \times 10^{24}\)[/tex] atoms of LiCl, we can set up the conversion:
[tex]\[ \text{Number of moles} = \frac{\text{Number of entities}}{\text{Avogadro's constant}} \][/tex]
[tex]\[ \text{Number of moles} = \frac{4.81 \times 10^{24}}{6.022 \times 10^{23}} \approx 8 \][/tex]
Therefore, there are approximately 8 moles of LiCl formula units in [tex]\(4.81 \times 10^{24}\)[/tex] atoms.
The question probable maybe:
How many moles are in [tex]4.81*10^2^4[/tex] atoms of formula units of LiCl?
The student's question is about the amount of lithium (4.81*10^24 atoms), which relates to its atomic properties and applicability in technologies like lithium ion batteries.
Explanation:The question involves calculating the amount of lithium using Avogadro's number and understanding lithium's atomic structure and isotopes. Lithium (Li), with an atomic number of 3, has 3 protons and often appears as its isotope lithium-7, which has 4 neutrons. The mass number of lithium-7 is 7, indicating it has a mass of 7.016 u. The electron configuration for lithium is 1s22s1, with the first two electrons filling the 1s orbital and the third electron in the 2s orbital. This knowledge is essential in fields like battery technology, where Lithium ion batteries are prominent. Lone pairs and London dispersion forces also play a role in the properties of lithium compounds, but the student's question is focused on the number of atoms, so those concepts are less directly relevant here.
What are three ways to increase the rate of dissociation of a solid
Three ways to increase the rate of dissociation of a solid are:
1. Increasing the surface area of the solute.
2. Increasing the temperature of the solvent.
3. Agitating the solute and solvent mixture.
Explanation:
The dissociation of a solid is defined as the separation of ions when an ionic compounds dissolve. The dissociation rate can be increased by increasing the surface area of the solute because it would get enough chance to interact with other particles, hence the rate of dissociation increases.
By increasing the temperature, the kinetic energy of the molecules increase thereby dissolving more of the solute particles.
Agitating affects dissociation rate because it helps solute particle to get distributed evenly and hence gets dissociate easily.
describe the nature and structure of an atom
Answer:
Atoms consist of three basic particles: protons, electrons, and neutrons. The nucleus (center) of the atom contains the protons (positively charged) and the neutrons (no charge). The outermost regions of the atom are called electron shells and contain the electrons (negatively charged).
Explanation:
What unit is used to measure cell potential?
A. electron
Kelvin
oxidation number
OD. volt
Volt is the unit to measure cell potential.
Explanation:
The cell potential is the measure of potential difference in the two halves of the electrochemical cell.
It is the measure of how much voltage exists between the two halves of the battery. The unit of volt is joule/coulomb. The cell potential is measured by voltmeter.
The energy per unit charge from the oxidation-reduction reaction to drive the reaction is cell potential.
sorry about the little cut off
Answer:
1.0876 M
Explanation:
Initial Volume of NaOH (V1) = 1234.56 mL
Convert mL to L
1 mL = 0.001 L
1234.56 mL = 1234.56 x 0.001 = 1.2346 L
Initial Molarity of NaOH (M1) = 3.33 M
final Volume of NaOH (V2) = 3.78 L
Final Molarity of NaOH (M2) = ?
Solution:
As we diluting the concentrated NaOH
Note: Molarity = M= mol/L
So, Dilution formula will be used
M1 V1 = M2 V2
Put values in above equation
3.33 mol/L x 1.2346 L = M2 x 3.78 L
Rearrange the above equation
M2 = 3.33 mol/L x 1.2346 L / 3.78 L
M2 = 4.1112 mol / 3.78 L
M2 = 1.0876 M
So, the final molarity of the diluted Sodium hydroxide (NaOH) solution is 1.0876 M.
Rewrite this measurement with a simpler unit, if possible.
8.3 kg•m^2/ s^2
Final answer:
The measurement 8.3 kg·m^2/s^2 can be rewritten as 8.3 joules (J), as 1 kg·m^2/s^2 is equivalent to 1 joule.
Explanation:
The measurement 8.3 kg·m^2/s^2 can be simplified to a simpler unit which is the joule (J). In physics, the unit of energy, work, and heat is the joule, and it is defined as 1 kg·m^2/s^2. Hence, the given measurement of 8.3 kg·m^2/s^2 is equal to 8.3 joules (J). The measurement 8.3 kg·m^2/s^2 can be simplified to a simpler unit which is the joule (J). In physics, the unit of energy, work, and heat is the joule, and it is defined as 1 kg·m^2/s^2.The measurement 8.3 kg·m^2/s^2 can be simplified to a simpler unit which is the joule (J). In physics, the unit of energy, work, and heat is the joule, and it is defined as 1 kg·m^2/s^2. Hence, the given measurement of 8.3 kg·m^2/s^2 is equal to 8.3 joules (J). This conversion is based on the fact that energy (E) can be expressed in terms of mass (m), the acceleration due to gravity (g), and height (h) in the equation E = mgh, with g typically approximated as 10 m/s^2 for convenience. Hence, the given measurement of 8.3 kg·m^2/s^2 is equal to 8.3 joules (J). This conversion is based on the fact that energy (E) can be expressed in terms of mass (m), the acceleration due to gravity (g), and height (h) in the equation E = mgh, with g typically approximated as 10 m/s^2 for convenience.The measurement 8.3 kg·m^2/s^2 can be simplified to a simpler unit which is the joule (J). In physics, the unit of energy, work, and heat is the joule, and it is defined as 1 kg·m^2/s^2. Hence, the given measurement of 8.3 kg·m^2/s^2 is equal to 8.3 joules (J). This conversion is based on the fact that energy (E) can be expressed in terms of mass (m), the acceleration due to gravity (g), and height (h) in the equation E = mgh, with g typically approximated as 10 m/s^2 for convenience.This conversion is based on the fact that energy (E) can be expressed in terms of mass (m), the acceleration due to gravity (g), and height (h) in the equation E = mgh, with g typically approximated as 10 m/s^2 for convenience.
Which of the following environmental
concerns does not support the main idea
of this cartoon that people are observing
unusual weather patterns?
Answer:
4 overharvesting of seafood. All of the other options directly cause global warming/ climate change.
Explanation:
The cartoon suggests that people are observing unusual weather patterns, and among the environmental concerns listed, deforestation is the one that does not support the main idea.
The cartoon suggests that people are observing unusual weather patterns. To identify the environmental concern that does not support the main idea of the cartoon, we need to examine the choices provided.
However, based on the information given, we can make an educated guess.
1. Deforestation: Deforestation refers to the clearing or removal of trees from a forested area. While deforestation can have various environmental impacts, such as habitat destruction and soil erosion, it is not directly related to observing unusual weather patterns. Therefore, deforestation could be the environmental concern that does not support the main idea of the cartoon.
2. Air pollution: Air pollution refers to the presence of harmful substances in the air, such as gases and particles. While air pollution can affect weather patterns to some extent, it is not necessarily an unusual weather pattern itself. Therefore, air pollution may not be the environmental concern that does not support the main idea of the cartoon.
3. Global warming: Global warming refers to the long-term increase in Earth's average temperature due to human activities, primarily the emission of greenhouse gases. Global warming can lead to various changes in weather patterns, including more frequent and intense extreme weather events. Therefore, global warming is likely to support the main idea of the cartoon.
4. Water scarcity: Water scarcity refers to the lack of sufficient water resources to meet the demands of a particular region or population. While water scarcity can be influenced by changes in weather patterns, it is not necessarily an unusual weather pattern itself. Therefore, water scarcity may not be the environmental concern that does not support the main idea of the cartoon.
Based on the analysis above, deforestation is the environmental concern that does not support the main idea of the cartoon, which is about people observing unusual weather patterns.
What observations can you make about the valence electrons in the following columns of the periodic table?
-Column 1:
-Column 2:
-Transition Metal Columns:
-Columns 3–7:
-Column 8:
Answer:
Column 1. They have one valence electron
Column 2. They have 2 valence electrons
Transition metal column. Variable oxidation states
Column 3–7. Valence electron ranges from 3 to 7 electrons
Column 8. Completely filled i.e no valence electron
Explanation:
Each column of the periodic table represents elements with a specific number of valence electrons. Columns 1 and 2 have one and two valence electrons respectively, and are known for their reactivity. Transition metals typically have one or two, Columns 3-7 have 3 to 7, and Noble Gases in Column 8 have a full shell of eight, making them unreactive.
Explanation:We can categorize columns, or groups, of the periodic table by the number of valence electrons, which are the outermost electrons in an atom that participate in chemical bonding.
Column 1: These elements, also known as alkali metals, have a single valence electron in their outermost shell. These elements are highly reactive due to their tendency to lose this electron and achieve a stable configuration.Column 2: These are the alkaline earth metals, which have two valence electrons. They are less reactive than alkali metals but will still readily lose their valence electrons to achieve stability. Transition Metal Columns: These contain transition metals which typically have one or two valence electrons, although this can be more complex due to the filling of inner d orbitals.Columns 3–7: Elements in these groups have 3 to 7 valence electrons respectively. Many form covalent bonds by sharing their valence electrons with other atoms.Column 8: Known as the Noble Gases, these elements possess a stable full set of 8 valence electrons (except for Helium which has 2). They are very unreactive due to their stable electronic configuration.Learn more about Valence Electrons here:
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What is the volume of a 5.30g piece of aluminum? The density for aluminum is 2.70gmL.
The volume of the piece of aluminum is 1.96 mL
Explanation:
Density is the relationship of the mass of a substance and its volume.
In this case, the mass of aluminum is 5.30 g and the density is 2.70 g/mL
The formula to apply is;
D=M/V where D is density in g/mL, M is mass in g and V is volume in mL
2.70=5.30/V
V=5.30/2.70 =1.96 mL
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Which of the following best describes the
relationship between frequency and wavelength.
of electromagnetic waves?
A. If the frequency remains constant, the wavelengh
increases
B. The wavelength decreases as the frequency decreases
c. The frequency increases as the wavelengh decreases
D. If the wavelengh remains constant, the frequency
Increases.
Answer:
b. the higher the frequency of a wave, the more energy it has
Explanation:
The relationship between frequency and wavelength of electromagnetic waves is an inverse relationship. As the frequency increases, the wavelength decreases, and vice versa.
Explanation:The correct relationship between frequency and wavelength of electromagnetic waves is option C: The frequency increases as the wavelength decreases.
This is known as the inverse relationship between frequency and wavelength. As the frequency increases, the wavelength decreases, and vice versa. This can be explained using the formula v = fλ, where v is the velocity of the wave, f is the frequency, and λ is the wavelength. Since the velocity remains constant, as the frequency increases, the wavelength must decrease to maintain the equation.
For example, in the electromagnetic spectrum, as we move from radio waves to microwaves, the frequency increases and the wavelength decreases. Conversely, as we move from infrared waves to visible light waves, the frequency increases and the wavelength decreases as well.
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I NEEDD HELLLPPPP!!!!! 20 POINTS
Newton's universal law of gravitation states that all objects attract each other with a force_____ proportional to the product of their masses and____ proportional to the square of the distance between their centers. When considering objects on the surface of the Earth, the force is_____ proportional to the product of the mass of the object and the____ due to_____ at the Earth's surface. Since the Earth is____ than any object under consideration, the object is drawn______ the Earth.
Word bank: all
acceleration
away from directly
directly
gravity
inversely
larger
smaller
some
toward
Newton's universal law of gravitation states that all objects attract each other with a force directly proportional to the product of their masses and inversely proportional to the square of the distance between their centers.
What is gravitational force?Gravitational force is a kind of attraction force which acts between two objects and it is represented as:
G = m₁m₂/r²
From the formula it is clear that:
Gravitational force is directly proportional to the product of the masses of two objects.And inversely proportional to the square of the distance between the given objects.If any object is present at the surface of the earth then acceleration due to gravity acts on the object.And we know that size of earth is larger than any other objects, so force is more towards that.Hence correct options are directly, inversely, directly, acceleration, gravity, larger and toward respectively.
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How many significant figures are in the number 50.5
Answer:
There are 3 significant numbers in the number 5.05
Explanation:
Which outcome is not caused by gravitational force?
Weightlessness or microgravity experienced by astronauts is not directly caused by gravitational force, as they are in continuous free-fall while orbiting the Earth. Gravity is a force that acts without physical contact and keeps celestial bodies in their orbits.
Explanation:The outcome not caused by gravitational force is weightlessness or microgravity in an orbiting spacecraft. This may seem counterintuitive as gravity is always present; however, an astronaut in orbit is in a state of free-fall, constantly accelerating towards the Earth but also moving forward, causing a sensation of weightlessness. Gravity affects us on Earth by pulling objects toward the center of the Earth, it is the force responsible for objects falling, and it keeps celestial bodies in orbit, like the moon around Earth, or Earth around the sun. However, near a black hole, for instance, the gravitational pull is so extreme that it can tear matter from nearby objects due to its intense tidal forces.
Gravitational force is a force that acts at a distance and is expressed by a formula that is valid everywhere in the universe. This is evident in phenomena like the orbit of planets and moons, the orbits of stars in a galaxy, or the clustering of galaxies. It's important to note that while gravity is weak compared to the other fundamental forces in nature, such as electromagnetic, strong nuclear, and weak nuclear forces, it is the dominant force in large-scale interactions where the other three forces can be negligible.
2. Which number is not a coefficient in the equation,
2C6H14 + 190212C02 + 14H20?
A 6 B 12 C 14 D 19
1
1
Answer: A. 6
Explanation: It is not present in the balanced chemical equation. Therefore it is not part of the coefficient in the reaction of the substances.
Temperature and Energy do not have any affect on the changes of states of matter.
Answer:
False
Explanation:
The diagram shows the movement of particles from one end of the container to the opposite end of the container. A cylindrical container is shown sealed at the top and bottom, with a solid layer with one small hole in it in the middle. The top part of the container has many small balls in it; the bottom part has only 4 balls. Arrows point down through the hole in the center layer. Which event is most likely occurring? diffusion because particles move from regions of high concentration to regions of low concentration diffusion because particles move from regions of low concentration to regions of high concentration effusion because there is a movement of a gas through a small opening into a larger volume effusion because there is a movement of a gas through a large opening into a smaller volume
Answer:
C. effusion because there is a movement of a gas through a small opening into a larger volume
Explanation:
Effusion makes fluid/gas molecules move to the container with less pressure or larger volume. In diffusion, the movement should work two ways even though one side might receive more. But in effusion, the movement is rather one way.
This case shows how effusion work because its not the concentration that makes the balls moving to the bottom part of the container. No ball moving from bottom container to top either.
Answer:
C. effusion because there is a movement of a gas through a small opening into a larger volume
Explanation:
got it right on edg
Many things can cause an organism to become extinct. Here are some possible causes of extinction. Select the human causes of extinction.
Question 7 options:
Global warming
Pollution
Habitat destruction
Disease
i will give brainiest answer to the right person.
Order the theories from oldest to most recent.
1 Electrons move about a positively charged nucleus in clouds that are defined by probabilities.
2 Atoms are tiny indivisible particles that make up all mater.
3 Atoms consist of mostly empty space with a dense nucleus of positive charge.
4 Negatively charged electrons are embedded in a mass of positive charge. 5 Electrons occupy specific energy levels surrounding a positively charged nucleus.
Answer:
Explanation:
The following are the order of point from oldest to most recent
1. Atoms are tiny indivisible particles that make up all mater.
it is Postulate of Dalton's atomic theory. this theory was put forward in 1803
2. Negatively charged electrons are embedded in a mass of positive charge.
In 1897 J.J Thomson discovered that atom consist of tiny negatively charged particles called electrons that are uniformly spread in +vely charged matrix this model called as plum pudding model.
3. Atoms consist of mostly empty space with a dense nucleus of positive charge.
While doing experiment on gold foil Rutherford presented a model in 1909 and stated that atom consist mostly empty space with dense nucleus.
4. Electrons occupy specific energy levels surrounding a positively charged nucleus.
Niels Bohr in 1913 put forward a model to explain atomic orbitals/energy level. This is a postulate of Bohr model.
5. Electrons move about a positively charged nucleus in clouds that are defined by probabilities.
In 1926 Erwin Schrödinger explain the wave function of electrons and its probability.
1. How many Nitrogen atoms are there in 4.58 mole of N.O.?
Answer: 1.29 x 10^24 atoms of Nitrogen is present
Explanation:
molar mass of NO = 14 +16 = 30g/mol
number of moles of NO = 4.58mol
number of moles of Nitrogen in NO is = (14/30)x4.58= 2.1373 moles
To get the number of atoms of Nitrogen we use Avogadro's number
Number of atoms of Nitrogen= mole fraction of Nitrogen x Avogadro's constant = 2.1373 x 6.02 x 10^23 = 1.29 x 10^24 atoms
Which term describes a section of Earht's structure below moving continents as parts of large plates?
A. continental crust
B. divergent boundary
C. asthenosphere
D. earth core
"Asthenosphere" describes a section of Earth's structure below moving continents as parts of large plates.
Answer: Option C
Explanation:
The asthenosphere denoted as the upper mantle of a very sticky, mechanically weak and flexible area in the earth. It is located below the surface of the lithosphere at depths of about 80 and 200 km (in terms of miles, 50 and 120). The boundary is commonly called the lithospheric LAB - asthenosphere.
The asthenosphere is nearly solid, though some of its regions could be molten below mid-ocean ridges for an instance. The lower asthenosphere boundary isn't well defined. The asthenosphere's thickness depends primarily on the temperature.
Can someone answer this for me please
Answer: B. Heat from the lemonade moved into the ice
Explanation: The concept of heat flow is explains that heat always move from higher temperature to lower temperature. So the heat in the lemonade moves into the ice until they attain thermal equilibrium or equal temperature.
Active transport requires chemical energy. True False
Answer:
The answer is true
Explanation:
This process is called passive transport or facilitated diffusion, and does not require energy. The solute can move "uphill," from regions of lower to higher concentration. This process is called active transport, and requires some form of chemical energy.
Answer:
True
Explanation:
What is the mass of a glucose solution that fills a 0.500-L intravenous bottle if the density of the glucose solution is
1.15 g/mL?
Answer:
m = 575 g
Explanation:
Given data:
Volume of solution = 0.500 L (0.500×1000 = 500 mL)
Density of glucose solution = 1.15 g/mL
Mass of glucose solution = ?
Solution:
Formula:
d = m/v
d = density
m = mass
v = velocity
Now we will put the values in formula.
1.15 g/mL = m/500 mL
m = 1.15 g/mL × 500 mL
m = 575 g
How many moles of sodium atoms are contained in 3.5 moles of sodium sulfide
Answer:
7 moles
Explanation:
The molecular formula of sodium sulfide is Na_2S
One molecule of Sodium sulfide has 2 atoms of sodium and one atom of sulfur
1 mole of Sodium sulfide has 2 moles of sodium and one mole of sulfur
so 3.5 moles of sodium sulfide will have 2× 3.5 moles of sodium atoms
i.e 2×3.5= 7 moles of sodium atom
Final answer:
In 3.5 moles of sodium sulfide (Na₂S), there are 7 moles of sodium atoms because each molecule of sodium sulfide contains two sodium atoms.
Explanation:
To calculate the number of moles of sodium atoms contained in 3.5 moles of sodium sulfide (Na₂S), we need to consider the chemical formula of the compound. Sodium sulfide is made up of two sodium atoms (Na) for every sulfide ion (S²⁻). Therefore, each mole of Na₂S will contain 2 moles of sodium atoms.
Using this stoichiometric relationship, the calculation for the number of moles of sodium atoms in 3.5 moles of sodium sulfide is as follows:
Number of moles of Na in Na₂S = Number of moles of Na₂S * Number of Na atoms per molecule of Na₂SNumber of moles of Na = 3.5 moles * 2 moles of Na/mole of Na₂SNumber of moles of Na = 7 molesTherefore, there are 7 moles of sodium atoms in 3.5 moles of sodium sulfide.what element is in the same family as Pb but it has fewer protons than Na
Answer:
Carbon
Explanation:
In a classroom, which comparison would a teacher most likely use for describing a mole?
Answer:
In a classroom, the comparison that a teacher would most likely use for describing a mole is: jar of jellybeans and a gram of salt crystals.
Explanation:
Consider a species in which dark brown fur is dominant relative to light brown fur.
Answer:
Explanation:
To interpret this pedigree, let’s start with information that we already know:
Brown is recessive, which means brown individuals must have the phenotype BB. In this pedigree, brown individuals are filled in.
Black is dominant, which means black individuals must have at least one B allele. Their phenotype could be either BB or BB. In this pedigree, black individuals are not filled in.
Figure 5 shows the same pedigree, but with information about the individual’s phenotype filled in.
The shaded individual, who is a brown female puppy, must have the phenotype BB. If she had any B alleles, she would be black because the black allele is dominant over the brown allele.
In order for the brown puppy to have the phenotype BB, she must have gotten two “b” alleles: one from each of her parents. We know that her parents are both black (because they are unshaped), which means they must have a least one “B” allele. This means that both parents must be heterogeneous: BB.
The three black puppies must have at least one “B” allele in order for them to be black in color. However, we can’t tell whether they are homologous dominant (BB) or heterogeneous (BB) since both of those phenotype would result in black color. One way to represent this on a pedigree is B-, meaning that the second allele could be either B or b.