What is the toto number of neutrons in an atom of 73 li
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
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.
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
Water is composed of one atom of oxygen and two atoms of
Answer:
Hydrogen.
Explanation:
You've probably seen "[tex]H_{2}0[/tex]" which is the formula for water. It means that there's 2 hydrogen atoms, and one oxygen atom, in one molecule of water.
Hope this helps! Feel free to mark me Brainliest if you feel this helped. :)
Answer:
the answer is H. (hydrogen)
which statement describes how technology has increased our information on Mars?
A. The Curiosity rover found sulfur compound in rocks.
B.The Curiosity rover located methane in soil samples.
C. The Curiosity rover detected carbon in organic molecules.
D. The Curiosity rover discovered helium in underground pockets.
Answer:
Either D or C. I'm so sorry if I got you the wrong answer
Answer:
c
Explanation:
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
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
The mass of 1 gram:
is kept as a standard platinum cylinder in France
equals 1 cm³
is .01 kg
equals the mass of 1 mL of water at 4°C
Answer:
C. equals the mass of 1 mL of water at 4°C
Explanation:
What is the mean of the data set [3, 2, 2, 12, 6, 5, 14,4)?
O2
O 7
Answer:
the mean is 6 but you don't have that as an option.
Explanation:
the mean is the average.
to find the mean you have to add all of your data first
3 + 2 + 2 + 12 + 6 + 5 + 14 + 4 = 48
then you have to divide your answer by how many numbers there are in total.
48 / 8 = 6
the mean is 6.
In a mixture of bromine-79 and bromine-81 isotopes. An atom of bromine-79 contains?
Answer:
Bromin-79
Explanation:
The isotope bromine-79 will contain 35 protons, 35 electrons and 44 neutrons.
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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The process by which vesicles move substances out of a cell is
A piece of metal is composed of atoms. Each atom in the metal contains 29 protons. How is the metal classified?
Answer:
The metal is Copper
Explanation:
Matter is composed of atoms, which is the smallest indivisible particle of an element. The atom of an element consists of three subatomic particles namely: proton, electron and neutron etc.
The proton, which is the positively charged particle, is equal to the electron, which is the negatively charged particle. The proton number of the atom is the ATOMIC NUMBER of an element.
In the periodic table, the element with atomic number 29, which also means proton number 29 is Copper (Cu).
Pure H2oboils at 100 ˚C and freezes at 0 ˚C. What is the melting point and boiling point of water
after the addition of potassium chloride
Answer:
Recall the colligative properties of freezing point depression and boiling point elevation.
In proportion to the molality product of the solute, (
i
m
), the boiling point will raise and the freezing point will decrease.
Now, consider tap water. You know this!
Is tap water pure water? Of course not! It's a solution of many ions of metals or other inorganic compounds.
Hence, it has a varied boiling and melting point, by definition.
Explanation:
The colligative properties like the boiling point elevation and freezing point depression depend on the solute concentration. The boiling point of the water will increase while the freezing point will decrease.
What are colligative properties?Colligative properties are the attributes that depend on the amount or the solute concentration rather than on the type or identity of the solute particle. They include freezing point depression, lowering of vapor pressure, osmotic pressure, and boiling point elevation.
The boiling point elevation is the increase of the solvent's boiling point by the addition of the solute. Potassium chloride is a salt and a non-volatile solute that increases the boiling point of the solution.
The freezing point depression is one of the colligative properties that states the direct relationship between the molality and the freezing point of the solvent. As potassium chloride is a non-volatile solute it decreases the freezing point of the substance.
Therefore, the boiling point will increase but the freezing point will decrease after the addition of potassium chloride.
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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:
What is the name for the type of graph shown in the image below?
Box-and-whisker
Histogram
Line
Scatter plot
Answer:
Scatter plot
Explanation:
Because the plot is scattered all over the place
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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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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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.
Pls help I am confused my sister got me sweating
Answer:
Im pretty sure its B. is released by salivary glands.
Explanation:
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
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
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.
How are contact forces and non-contact forces similar?
Answer:
Difference between Contact and Non-Contact Forces
There is no field linked with the contact force. There is always a field linked with non-contact force. The frictional force is an example of a contact force. Gravitational force is an example of a non-contact force.
Explanation:
And it is physics not chem.
Hope this helps u
Crown me as brainliest:)
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
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:
Which of the following is an example of work: bowling or reading? How do you know?
Living things help contribute to the water cycle.
A. true
B.false