Answer:
B. When one element replaces another element in a compound during a chemical reaction
30 POINTS
Why would a scientist revise a model? (choose the best answer)
Group of answer choices
to cover up evidence from a previous experiment
to show off to other scientists
to add unnecessary details to the model
in order to better explain what is happening during a phenomenon
When modeling it is important to (pick two)
Group of answer choices
show beginning, middle and end if it fits the phenomenon
only use one color
make sure there is only drawings and nothing written
use zoom in bubbles to show the unobservable
Which of the following is NOT a limitation of a model
Group of answer choices
inaccurate colors
the type of material used to create the model
a messy model
shapes that are an approximation
Answer:
First Question: in order to better explain what is happening during a phenomenon
Second Question: show beginning, middle and end if it fits the phenomenon; use zoom in bubbles to show the unobservable
Third Question: the type of material used to create the model
Explanation:
First Question: You would not revise a model to "cover up evidence," that's scientifically immoral and should not be done, and showing off to other scientists is not the point of revising something.
Second Question: You should use more than one color to differentiate different parts of the model, but don't overwhelm it with color. There should be some labels in the model, so some writing is necessary.
Third Question: Inaccurate color representation does not technically limit a model unless color scheme is important, so this could be an answer, but not likely. A messy model limits a model because it makes it hard to read. Approximating shapes is a limitation because it portrays an incorrect representation of what system the model is of. The type of material used to create the model is most likely the right answer.
10. What are the upper and lower extremes of
the moisture content of wood?
Photosynthesis happens in the _____
O: lower epidermis
O: upper epidermis
O: palisade layer
O: spongy layer
List the factors that cause low oxygen levels.
Answer:
Common causes of hypoxemia include:
Anemia.
ARDS (Acute respiratory distress syndrome)
Asthma.
Congenital heart defects in children.
Congenital heart disease in adults.
COPD (chronic obstructive pulmonary disease) exacerbation — worsening of symptoms.
Emphysema.
Interstitial lung disease
and many more.....
Identify the placement of items A-E using the drop-down menus.
A)
⇒No
⇒Yes
B)
⇒No
⇒Yes, when liquid or solution
⇒Yes, when solid
C)
⇒No
⇒Yes
D)
⇒No
⇒Yes
E)
⇒No
⇒Yes
Answer:
A=no
B= yes when liquid or solution
C=yes
D=no
E=yes
Explanation:
According to the given table, the placement of items A-E are
A) ⇒ No
B) ⇒Yes, when liquid or solution
C) ⇒Yes
D) ⇒No
E) ⇒Yes
What is conductivity and Malleability?
Malleability - Those metals that can be beaten into thin sheets with a hammer or any heavy object. For example - Cu, Au etc
Conductivity - Conductivity is the measure of the ease at which an electric charge or heat can pass through a material. For example - Metals are good conductors of heat and electrolytic solution is conductors of electricity.
Therefore, according to the given table, the placement of items A-E are
A) ⇒ No
B) ⇒Yes, when liquid or solution
C) ⇒Yes
D) ⇒No
E) ⇒Yes
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What is the function of the esophagus?
The esophagus functions primarily as a transport tube that directs the progression of food and fluids from the mouth to the stomach.
A sample is left on the desk over several hours. On examination, the crystals appear moist, andliquid is forming around them. The compound is classified as:
a. Stableb.
b. Deliquescent
c. Efflorescentd.
d. Hygroscopic
Answer:
c. Efflorescent
Explanation:
Some hydrated salts, when exposed to the atmosphere, give off part of all of their water of crystallization spontaneously to form a lower dehydrated or anhydrous salt. Such salts are known as efflorescent and the phenomenon is called Efflorescence.
Efflorescence occurs when the hydrate's aqueous vapor pressure is greater than the water vapor's partial pressure in the air. For example, because the vapor pressures of washing soda (Na2CO3·10H2O) and Glauber's salt (Na2SO4·10H2O) normally exceed that of the water vapor in the atmosphere, these salts effloresce (i.e., lose all or part of their water of hydration), and their surfaces assume a powdery appearance.
illustrate the respiratory system
I hope this has the information that you need
What does the name "atom" mean in
Greek?
It means indivisible
Answer:
The Greek root of atom is atomos, which means "indivisible," since the scientists who first gave the atom its name imagined it couldn't be split or divided into smaller pieces.
Explanation:
3.) Why is argon (Ar) larger than neon (Ne)?
Answer: Here u go!
Explanation:
The electron cloud of argon is thus larger and more polarized, able able to express mawr inter molecular forces Vander Waals forces, which results in a higher boiling point due to these increase forces. Due to this, the boiling point of argon is higher are gone. We can see its boiling point is 87.2 Kelvin's, whereas a neon and spoiling point is 24.5.
Hope this helps!
Explanation:
Argon has an atomic number of 18, while neon has an atomic number of 10.
The atomic radius is comprised of the atom’s nucleus and electron cloud. As you go down on the periodic table, the effective nuclear charge decreases. This results in more screening of the electrons
from the nucleus (decreasing the attraction between the nucleus and the electrons) resulting in a larger atomic radius.
However, because they’re both noble gasses, the size difference in this case can be easier described by the number of particles in each atom.
Argon has 18 protons, 18 electrons and 22 neutrons.
Neon has 10 protons, 10 electrons and 10 neutrons.As you can see, argon has more “stuff.”
The increase in protons and electrons in particular results in a larger electron cloud, which means a much larger atomic radius than in neon.
i hope it helps u :)
If you added an excess of sodium phosphate dodecahydrate to 4.512 g barium chloride dihydrate, how many grams of barium phosphate could you synthesize
Answer:
3.35g of Ba3(PO4)2
Explanation:
The balanced chemical equation is given as;
3 BaCl2 + 2 Na3PO4 → 6 NaCl + Ba3(PO4)2
Fro the reaction;
3 mol of BaCl2 (624g) reacts wth 2 mol of Na3PO4 (327.88g) to form 1 mol of Ba3(PO4)2 (601.93g)
Since Na3PO4 is in excess, the limiting reactant is; BaCl2. It would determine how much of Ba3(PO4)2 is formed.
624g of BaCl2 = 601.93g of Ba3(PO4)2
4.512g of BaCl2= xg of Ba3(PO4)2
x = 4.512g * 601.93g / 624g
x = 3.35g of Ba3(PO4)2
The mass of barium phosphate synthesized is 3.612 g.
The equation of the reaction is;
3 BaCl2.2H2O + 2 Na3PO4.12 H2O → 6 NaCl + Ba3(PO4)2 + 14H2O
Molar mass of barium chloride dihydrate = 244.26 g/mol
The number of moles of barium chloride dihydrate = 4.512 g/244.26 g/mol
= 0.018 moles
From the balanced reaction equation shown;
If 3 moles of barium chloride dihydrate yields 1 mole of barium phosphate
0.018 moles of barium chloride dihydrate yields 0.018 moles × 1 mole/3 moles
= 0.006 mole of barium phosphate
Mass of barium phosphate = 602 g/mol × 0.006 mole
= 3.612 g
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Predict: Note the type of reaction you expect for the reactants Kl and Pb(NO3)2
Answer:
double replacement
Explanation:
just did it
Answer:
Double replacement
Explanation:
Which phrase is not an example of intercellular communication?
A chemical messengers dock onto receptors of adrenal gland
B chemical signal from pituitary gland to adrenal gland
C electrical signals pass between heart cells
D a vesicle encloses over a nutrient molecule
Answer: The answer is D
Explanation: I took the quiz just now and got it right
The correct answer is:
D.(a vesicle encloses over a nutrient molecule)
I took the test, hope this helps!
Which reason best explains why metals are malleable?
A. because they have delocalized electrons
B. because they have localized electrons
C. because they have ionic bonds
D. because they have rigid bonds
Answer:
A
Explanation:
because they have delocalized electrons
Metals are malleable because they have delocalized electrons which are capable of forming ionic bonds.
What is an ionic bond?
Ionic bond or electrovalent bond is a type of bond which is formed between two elements when there is an exchange of electrons which takes place between the atoms resulting in the formation of ions.
When the atom looses an electron it develops a positive charge and forms an ion called the cation while the other atom gains the electron and develops a negative charge and forms an ion called the anion.
As the two atoms are oppositely charged they attract each other which results in the formation of a bond called the ionic bond.Compounds having ionic bonds are malleable and have high melting points.They are also brittle in nature.
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A chemist working as a safety inspector finds an unmarked bottle in a lab cabinet. A note on the door of the cabinet says the cabinet is used to store bottles of pentane, tetrahydrofuran, carbon tetrachloride, methyl acetate, and ethanolamine. The chemist plans to try to identify the unknown liquid by measuring the density and comparing to known densities. First, from his collection of Material Safety Data Sheets (MSDS), the chemist finds the following information: liquid density pentane tetrahydrofuran carbon tetrachloride methyl acetate ethanolamine Next, the chemist measures the volume of the unknown liquid as and the mass of the unknown liquid as . Calculate the density of the liquid. Round your answer to significant digits. Given the data above, is it possible to identify the liquid
Answer:
The liquid can be identified
Explanation:
Given that density is defined as mass per unit volume.
We have the following information regarding the unknown liquid;
Mass= 1.40 kg = 1400 g
Volume = 1378 cm^3 = 1378 ml
Density of unknown liquid = 1400/1378 = 1.012 g/ml this is approximately 1.0 g/ml
It is possible to identify the liquid, the liquid is ethanolamine
Photons are emitted as electrons in the atom jump up in energy. true or false?
Answer:
true
Explanation:
photons are emitted when electrons move from from a lower energy level to a higher energy level
The purpose for witch something is designed or exists
Answer:
to help
Explanation:
to help
Need help ASAP..... (0.567 liters of H2O is how many moles of H2O? HINT: 1 mL H20 = 1 gram
H20)
Answer:
31.5 moles
Explanation:
Volume of H2O = 0.567 L
Number of mole of H2O =.?
Next, we shall convert 0.567 L to millilitres (mL). This can be obtained as follow:
1 L = 1000 mL
Therefore,
0.567 L = 0.567 L × 1000 mL / 1 L
0.567 L = 567 mL
Thus, 0.567 L is equivalent to 567 mL.
Next, we shall convert 567 mL to grams (g). This can be obtained as follow:
1 mL of H2O = 1 g
Therefore
567 mL of H2O = 567 g of H2O
Finally, we shall determine the number of mole in 567 g of H2O. This can be obtained as follow:
Mass of H2O = 567 g
Molar mass of H2O = (2×1) + 16
= 2 + 16 = 18 g/mol
Mole of H2O =?
Mole = mass /Molar mass
Mole of H2O = 567 /18
Mole of H2O = 31.5 moles
Which of the following is an example of a pure substance?
A. beer
C. halo-halo
B. ethyl alcohol
D. silver spoon
Pls help I dont get science so pls help me
What type of bond is present between two atoms of zinc in a nickel
Answer:
Pure covalent
Explanation:
To know the type of bond between two atoms you must find the electronegativity difference of them:
If electronegativity difference is:
< 0.4: Pure covalent.
Between 0.4 and 1.8: Polar covalent.
> 1.8: Ionic.
The electronegativity of Zn is 1.65 and Ni is 1.91. Electronegativity difference is:
1.91 - 1.65 = 0.26
That means the type of bond is:
Pure covalentWhen ignited, a uranium compound burns with a green flame. The wavelength of the light given off by this flame is greater than that of _____.
Answer:
Ultraviolet light.
Explanation:
Uranium is a natural radioactive chemical element with the chemical symbol "U" and an atomic number of 92. Uranium is used for generating nuclear fuels which are typically used in powering atomic bombs and nuclear reactors in the field of electricity generation.
When ignited, a uranium compound burns with a green flame. The wavelength of the light given off by this flame is greater than that of ultraviolet light which typically ranges from 100nm to 400nm. Where, nm is represents nanometer.
Basically, when ignited, a uranium compound burns with a green flame having a wavelength of 4.30 x 10^-7m to 5 x 10^-7m.
Balance the following equation. ZnCl2 + (NH4)3PO4 ->__Zn3(PO4)2 + NHACI
Answer:
3ZnCl2 + 2(NH4)3PO4 → Zn3(PO4)2 + 6NH4Cl
Explanation:
Zinc Chloride + Tribasic Ammonium Phosphate = Zinc Phosphate + Ammonium Chloride
Reaction Type
Double Displacement (Metathesis)
Reactants
Zinc Chloride - ZnCl2
Zinc(II) Chloride Zinc Chloride, Anhydrous Dichlorozinc Butter Of Zinc Zinc Chloride Zn-65
Molar Mass of ZnCl2 Oxidation State of ZnCl2
Tribasic Ammonium Phosphate - (NH4)3PO4
Ammonium Phosphate
Molar Mass of H12N3O4P Oxidation State of H12N3O4P
Products
Zinc Phosphate - Zn3(PO4)2
Zinc(II) Phosphate
Molar Mass of O8P2Zn3 Oxidation State of O8P2Zn3
Ammonium Chloride - NH4Cl
Amchlor Ammoneric Ammonium Muriate Darammon Sal Ammonia Sal Ammoniac Salammonite Salmiac
Molar Mass of ClH4N Oxidation State of ClH4N
What is the law of conservation of matter?
A.Matter can never be changed.
B.Matter can never mix or rearrange.
C.Matter cannot be created or destroyed.
D.matter will always break down.
Considering the definition of the law of conservation of matter, the law of conservation of matter establishes that matter cannot be created or destroyed (option C).
Law of conservation of matterThe law of conservation of matter holds that, within a closed system, the amount of matter involved in a chemical reaction is constant, meaning a closed system means an environment that isolates the components involved in the reaction from the outside.
In other words, this law establishes that the mass of the reactants consumed is equal to the mass of the products obtained, even though they have been transformed into each other.
In other words, the law of conservation of matter states that matter is neither created nor destroyed during a chemical reaction, it is only transformed.
SummaryIn summary, the law of conservation of matter establishes that matter cannot be created or destroyed (option C).
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Sanjay is learning about the elements that make up Earth’s crust. Ms. Richards, his Earth science teacher, gives him an element and asks him to determine which element from Earth’s crust it is. She also provides Sanjay with this table. Sanjay weighs the element and finds that it has a mass of 17.98 g. By placing the element in water, he determines the volume of the substance to be 2.2835 mL.
Based on the table from Ms. Richards, what element from Earth’s crust did Ms. Richards gave to Sanjay?
A) iron
B) calcium
C) aluminum
D) silicon
Answer:
Iron
Hope this helps! Stay safe!
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Answer:iron
Explanation:
The phase of matter most likely to be present at absolute zero would be:
A)
plasma
B)
gas
C)
liquid
D)
solid
Answer:
D solid
Explanation:
What was the average speed of the truck for this trip?
Answer:
31.67 mph
Explanation:
To calculate the average speed of the truck, we must first obtain the total distance travelled by the truck followed by the total time taken for the truck to cover the distance travelled.
The following data were obtained from the question include:
Total distance) = 30 + 45 + 50 + 65 = 190 miles
Total time = 1 + 2 +1 +2 = 6 hours
Average speed =.?
Average speed = Total distance / Total time
Average speed = 190 /6
Average speed = 31.67 mph
Therefore, the average speed of the truck is 31.67 mph
Which would most likely be the pH of a highly-corrosive acid? 1 5 8 11
Answer:
it is 1 because of it is below 7 then it will be dangerous for humans
The pH of the highly corrosive acid, given the data from the question is 1
What is pH ?This is simply a measure of the acidity / alkalinity of a solution.
The pH measures the hydrogen ion concentration while the pOH measures the hydroxide ion concentration
pH scaleThe pH scale is a scale that gives an understanding of the variation of the acidity / alkalinity of a solution.
The scale ranges from 0 to 14 indicating:
0 to 6 indicates acid 7 indicates neutral 8 to 14 indicate basicNOTE: The lesser the pH of a substance, the more acidic (corrosive) it is and the greater the pH of the substance, the less acidic (corrosive) it is.
With the above information about pH, we can conclude that the pH of the highly corrosive acid, given the data is 1
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14. Identify the type of reaction: Pb + 2 AgCl → 2 Ag+ PbCl2
a. Combination/synthesis
b. Decomposition
c. Double replacement
d. Single replacement
When all colors of light are absorbed, what do you see?
Black
Orange
Pink
Yellow
Answer:
Black
Explanation:
hope it helps
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