Scientists utilize models for a variety of different purposes, but each type of scientific model has limitations. What might
be a limitation of existing solar system models?
a. They are not based on experimentation.
b. They are used for prediction.
C. They cannot be changed.
d. They are based on current knowledge,
Please select the best answer from the choices provided
А
B
С
D
Answer:
D.They are based on current knowledge.
Explanation:
Guy above me is wrong
Find the number of moles of iron atoms obtain
from 320kg of iron (3) oxide
Answer:
320 kg of iron(III) oxide contain 4007.76 moles of iron atom.
Explanation:
Given data:
Mass of iron(III) oxide = 320 kg (320000 g)
Number of moles of iron atoms = ?
Solution:
First of all we will calculate the number of moles of iron(III) oxide.
Number of moles = mass/molar mass
Number of moles = 320000 g/ 159.69 g/mol
Number of moles = 2003.88 mol
1 mole of Fe₂O₃ contain 2 moles of iron atom.
2003.88 moles of Fe₂O₃ contain,
2003.88 ×2 = 4007.76 moles of iron atom.
Which changes MUST happen for elements to become a compound
Answer:
Chemical changes in compounds happen when chemical bonds are created or destroyed. Then the molecular structure changes; new molecules form and a new substance is created. Often heat is used to begin a chemical change, as when baking a cake. Another example of a chemical reaction is the rusting of a metal trash can.
Hope this helps you Do mark as brainliest ✌️An element is constituted of only atoms and no other entities are present in it. Whereas a chemical compound is a substance made up of various identical molecules of the same or different atoms.
The atoms of the same or different species bond together to form a compound.
Chemical bonding is present among them that cannot be simply separated.The compounds can have ionic, covalent and hydrogen bonds present in them.When the new atoms combine the structure changes of the new molecule formed.To learn more about compounds and atoms follow the link:
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The graph shows the average monthly rainfall for a
forested area.
In which month is a high alert for fire danger most
likely?
A. April
B. August
C. May
D. October
Answer:
The Answer would be A. April
Explanation:
Least amount of rainfall out of all the months we have to choose from.
The lowest energy state of an atom is its
A. Highest-occupied energy level.
B. Principle quantum number.
C. Electron configuration.
D. Ground state.
Answer:
Principle quantum number.
Explanation:
Which of the following representations shows the correct placement of trophic levels?
Secondary Consumers
Primary Consumers
Producers
A sample of an ideal gas has a volume of 2.38 L at 283 K and 1.03 atm. Calculate the pressure when the volume is 1.97 L and the temperature is 307 K.
Gas Has A Volume Of 2.21 L At 287 K And 1.11 Atm. Calculate The Pressure When The Volume Is 1.03 L And The Temperature
Explanation:
True or false: An oxidation number is not the same as an actual charge on an ion. True false question. True False
Answer:
True
Explanation:
They are actually the same
The answer is False.
The oxidation number is the number of electrons removed or added to an element or compound. This is also equal to the charge on the ion.
For example, if Sodium atom loses one electron, it becomes oxidized to the + 1 state.
Na → Na⁺ + e⁻.
So, the oxidation number of Sodium is the charge on the Sodium ion which is + 1.
So, the oxidation number is equal to the charge on the ion.
So, the answer is False.
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Who would most likely be required to work with sodium hydroxide?
a plumber
a gardener
a bricklayer
a mechanic
Answer:
i think plumber
Sodium hydroxide is generally referred to as caustic soda used in soaps and cleaners. A plumber would most likely be required to work with sodium hydroxide. Hence, option A is correct.
What is the use of sodium hydroxide?
Soaps, paper, explosives, dyes, and petroleum are all made with sodium hydroxide. The presence of sodium hydroxide in a cleanser or a homemade aqueous solution converts these disconcerting fats into soaps, which are easily removed by water.
They have no odor and no color making them react with water and strong acids to produce salts. They are considered ionic compounds with sodium cation and chloride anion. They also are used in oxide coating and cleaning of metals.
Therefore, option A. plumber will most likely use sodium hydroxide.
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Where is the north pole of the bar magnet, based on the magnetic field lines
shown?
Answer:On the Right End
Explanation: Trust me I just got it wrong on APEX to answer it for y’all On the right end is the correct answer
Answer:
Right end
Explanation:
Just did the quiz
A type of substance containing atoms of two or more different elements that are chemically bonded together is referred to as a
Answer:
Compound
Explanation:
Read the statement below and decide if it represents physical change or chamical change.
Iron is heated, causing it to melt.
O Physical Change
Chemical Change
3. Using the periodic table,
What is the average atomic mass of bromine?
What is the average atomic mass of magnesium?
How do your calculated answers in #1 and #2 compare to those on the periodic table?
Answer:
79.904 u for bromine
24.305 u
Not really sure what the 3rd question is asking
Explanation:
Pls help I am confused my sister got me sweating
Answer:
Im pretty sure its B. is released by salivary glands.
Explanation:
Living things help contribute to the water cycle.
A. true
B.false
the density of a wooden block that has a volume of 5 cm3 & a mass of 30.5 g
Formula: ____________
Mass = ____
Volume = ____
Density = ____
Answer:
The answer is 6.10 g/cm³Explanation:
The density of a substance can be found by using the formula
[tex]density = \frac{mass}{volume} \\[/tex]
From the question
mass = 30.5 g
volume = 5 cm³
We have
[tex]density = \frac{30.5}{5} \\ [/tex]
We have the final answer as
6.10 g/cm³Hope this helps you
HELPPPPP plssssss!!!!!! Is the brain of the cell living or non-living?
Answer: living
Explanation: The brain of a cell is living. All parts of the cell must be alive in order for the human body to revive. The brain of a cell controls the cells, and cells are the basic block of human life.
Acetylsalicylic acid (C9H8O4) is a monoprotic acid commonly known as aspirin. A typical aspirin tablet, however, contains only a small amount of the acid. In an experiment to determine its composition, an aspirin tablet was crushed and dissolved in water. It took 14.40 mL of 0.1466 M NaOH to neutralize the solution. Calculate the number of grains of aspirin in the tablet. (One grain = 0.0648 g and the molar mass of aspirin = 180.2 g/mol.)
Answer:
6 grains
Explanation:
The equation of the reaction between NaOH and aspirin is;
C9H8O4(aq) + NaOH (aq) ------>C9H7O4Na(aq) + H2O(l)
Amount of NaOH reacted = concentration × volume = 0.1466 M × 14.40/1000 L = 2.11 × 10^-3 moles
Given that aspirin and NaOH react in a mole ratio of 1:1 from the balanced reaction equation above, the number of moles of aspirin reacted is 2.11 × 10^-3 moles
Hence mass of aspirin reacted = 2.11 × 10^-3 moles × 180.2 g/mol = 0.38 g
If 1 grain = 0.0648 g
x grains = 0.38 g
x= 0.38 g/0.0648 g
x= 6 grains
The specific heat of silver is 0.24 J/g•°C. How many joules of energy are needed to warm 4.37 g of silver from 25.0°C to 27.5°C?
A. 2.6 J
B. 46 J
C. 0.14 J
D. 0.022 J
The heat energy needed to change the temperature of 4.37 gram of silver sample of specific heat 0.24 J/ g °C from a temperature of 25 to 27.5 °C is 2.6 J.
What is calorimetry ?Calorimetry is an analytical technique used to determine the heat energy absorbed or released by a system. The calorimetric equation relating the heat energy q with the mass of the substance m, specific heat c and temperature difference ΔT is given as:
q = m c ΔT.
Given that the mass of the sample of iron = 20 g
temperature difference ΔT = 27.5 - 25 = 2.5 °C
specific heat c = 0.24J/ g °C.
The heat energy absorbed by the sample is calculated as follows:
q = 4.37 g × 0.24 J/ g °C × 2.5 °C
= 2.6 J.
Therefore, the heat energy required to the raise the temperature of the sample of iron is 2.6 J.
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In two to three sentences, explain the trend for atomic size. Why does this trend occur?
Answer:
The number of energy levels increases as you move down a group as the number of electrons increases. Each subsequent energy level is further from the nucleus than the last. Therefore, the atomic radius increases as the group and energy levels increase. 2) As you move across a period, atomic radius decreases.
Explanation:
II. Pure magnesium metal is often found as ribbons and can easily burn in the presence of oxygen. When 3.86 g of magnesium ribbon burns with 155ml of oxygen at 1.0 atm and 275 K , a bright, white light and a white, powdery product is formed, magnesium oxide. How many grams of excess reactant remain?
Answer:
[tex]Excess=3.53g[/tex]
Explanation:
Hello,
In this case, the undergoing chemical reaction is:
[tex]2Mg(s)+O_2(g) \rightarrow 2MgO(s)[/tex]
Next, we identify the limiting reactant by computing the moles of magnesium oxide yielded by 3.86 g of magnesium and 155 mL of oxygen at the given conditions via their 2:1:2 mole ratios and the ideal gas equation:
[tex]n_{MnO}^{by \ Mg}=3.86gMg*\frac{1molMg}{24.3gMg}*\frac{2molMgO}{2molMg} =0.159molMgO\\\\n_{MnO}^{by \ O_2}=\frac{1atm*0.155L}{0.082\frac{atm*L}{molO_2*K}*275K} *\frac{2mol MgO}{1molO_2} =0.0137molMgO[/tex]
It means that the limiting reactant is the oxygen as it yields the smallest amount of magnesium oxide. Next, we compute the mass of magnesium consumed the oxygen only:
[tex]m_{Mg}^{consumed}=0.0137molMgO*\frac{2molMg}{2molMgO} *\frac{24.3gMg}{1molMg} =0.334gMg[/tex]
Thus, the mass in excess is:
[tex]Excess=3.86g-0.334g\\\\Excess=3.53g[/tex]
Regards!
Chemical properties can be observed without changing the substance
Answer:
chemical properties can only be measured only by changing a substance chemical identity
Explanation:
apex
A student heats 25 mL of water from 20°C to 96°C in a glass beaker. The
model represents the motion of the water molecules during heating.
Explain why some of the water molecules shown in the model have
longer arrows than other water molecules during heating.
Answer:
Because the have acquired energy from the heating process, that is why the start moving faster.
Explanation:
Hello.
In this case, since the initial liquid water molecules have a certain energy content, which makes them move with the relatively medium velocity characteristic in liquid-phase substances, once energy starts being added, it is evidenced that the molecules acquire more energy which is able to make them move faster.
In such a way, since the initial water molecules velocity is marked by a medium range arrows, meaning that the molecules are moving not-so-fast, not-so-slow but the heated water molecules are marked by longer arrows, meaning that they move faster, we infer that such velocity increase is due to the addition of heat due to the heating process from 20 °C to 96 °C (just before boiling).
Regards!
Molecular motion is the action of motion of the molecules or the particles in a specific direction. The molecules start moving faster due to the energy given by the heat.
What are the factors affecting molecular motion?The movement of the molecules or the particles in the system is affected by the temperature and the heat given to the system by the external source.
The initial molecules have relative speed and motion in the system and after the addition of the factors the energy of the motion of the particles gets affected.
When the temperature of the water in the beaker is increased then the average kinetic energy of the molecules also increases and hence the motion of the molecules increases.
The medium ranged arrows depict the average speed of the molecule movement in the medium, while the longer arrows suggest the fast-moving molecules of the water.
Therefore, the heat increases energy and in turn the molecular motion.
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An empty graduated cylinder weighs 45.8772 g. After 20.0 mL of a liquid is added, the cylinder and its contents weigh 77.7572 g. What is the density of the liquid in g/mL?
Answer:
1.59g/mL
Explanation:
(777.7572 – 45.8772)g / (20.0) ml = (31.8800 g) / (20.0 ml) = 1.59 g/ml
Ok here is the next one
I’m counting on you
Thanks.
food moves through the mouth by muscle movement
Help pls:)?
If the low power objective has 10X printed on it, what would be the total magnification when looking through the microscope?
Answer:
The magnification of the microscope is equal to the magnification of the ocular lens times the magnification of the objective lens. Since the objective lens has 10x printed on them at "low power". The total magnification would be 10 times 10.
Explanation:
i hope this helps C:
Calculate the density of an
object with a mass of 58g and a
volume of 20 mL.
Enter
Answer:
D = 2.9 g/mL
Explanation:
Density = Mass over Volume
D = m/V
Step 1: Define
m = 58 g
V = 20 mL
D = unknown
Step 2: Substitute and Evaluate for Density
D = 58 g/20 mL
D = 2.9 g/mL
The thermite reaction occurs when iron(III) oxide reacts with solid
aluminum. The reaction is so hot that molten iron forms as a product.
>
Fe2O3(s) + Al(s) → Fe(C) + Al2O3(s)
What mass of aluminum should be used in order to completely
consume 10.0 g Fe2O3(s)? If the reaction described produces 5.3 g
Al2O3(s), what is the percent yield?
Answer:
[tex]m_{Al}=3.38gAl[/tex]
[tex]Y=83.1\%[/tex]
Explanation:
Hello.
In this case, for the given balanced reaction:
[tex]Fe_2O_3(s) + 2Al(s)\rightarrow 2Fe(s) + Al_2O_3(s)[/tex]
For 10.0 g of iron (III) oxide (molar mass = 160 g/mol), based on the 1:2 mole ratio with Al (atomic mass = 27 g/mol), the required mass is then:
[tex]m_{Al}=10.0gFe_2O_3*\frac{1molFe_2O_3}{160gFe_2O_3} *\frac{2molAl}{1molFe_2O_3} *\frac{27gAl}{1molAl} \\\\m_{Al}=3.38gAl[/tex]
Moreover, as 5.3 g of aluminum oxide are actually yielded, from the 10.0 g of iron (III) oxide, we can compute the theoretical mass of aluminum oxide (molar mass = 102 g/mol) via their 1:1 mole ratio:
[tex]m_{Al_2O_3}=10.0gFe_2O_3*\frac{1molFe_2O_3}{160gFe_2O_3} *\frac{1molAl_2O_3}{1molFe_2O_3} *\frac{102gAl_2O_3}{1molAl_2O_3} \\\\m_{Al_2O_3}=6.38gAl_2O_3[/tex]
Thus, the percent yield (actual/theoretical*100%) turns out:
[tex]Y=\frac{5.3 g}{6.38 g}* 100\%\\\\Y=83.1\%[/tex]
Best regards.
How many electrons does 2Na+1 have
Answer:
So... for the element of SODIUM, you already know that the atomic number tells you the number of electrons. That means there are 11 electrons in a sodium atom. Looking at the picture, you can see there are two electrons in shell one, eight in shell two, and only one in shell three.
Explanation:
brainliest pleaseeee <3
Answer:
so there would be 2 electrons because
Explanation:
sodium has 11 electrons but if you look at the shels it onl has one electron (from the image im looking at) and the other shell only have one so theres 2 electrons
A cough syrup contains red dye #40, with a concentration of 4.68 x 10-3 M.a.If you dilute the cough syrup by adding 175 mL of water to a 250. mL sample of the cough syrup, what will be the final concentration?
How do I do this?
Answer:
[tex]M_2=2.75x10^{-3}M[/tex]
Explanation:
Hello.
In this case, since a dilution process is a process by which the concentration of a solution decreases due to the increase of volume by usually adding water, it is important to take into account that the moles remain unchanged:
[tex]n_1=n_2[/tex]
Whereas in terms of molarity (M=n/V) can be written as:
[tex]M_1V_1=M_2V_2[/tex]
In such a way, since the initial concentration is 4.68e-3 M and the volume of such solution is 250. mL, the final volume results from mixing 250 mL of this solution with 175 mL, that is, to a volume of 425 mL. Thus, the concentration turns out:
[tex]M_2=\frac{M_1V_1}{V_2} =\frac{4.68x10^{-3}M*250.mL}{425.mL} \\\\M_2=2.75x10^{-3}M[/tex]
Best regards.
If you dilute the cough syrup by adding 175 mL of water to a 250 mL sample of the cough syrup, the final concentration would be 0.00275 M
Using a simple dilution equation:
number of moles before dilution = number of moles after dilution
Recall that: number of moles = molarity x volume (MV)
Thus:
M1V1 = M2V2
In this case, M1 = 4.68 x 10-3 M, M2 = ? V1 = 250 mL, and V2 = 425 mL
M2 = 4.68 x 10^-3 x 250/425
= 0.00275 M
= 0.00275 M
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