Answer:
Br₂(l) + ΔV → Br₂(g)
Explanation:
When a chemical or phase change occurs during a chemical process some heat is absorbed or released. For the process of vaporization of a substance, the heat (Usually required) is ΔV (How many energy is required for the process occurs).
In the vaporization of Br2 there are required 7.4kcal/mol, Δv. The reaction is:
Br₂(l) + ΔV → Br₂(g)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:
Calculate the density of an
object with a mass of 20 g
and a volume of 2.3 mL.
Answer:
8.7g/mL
Explanation:
I used the density formula to solve. d=m/v= 20g/2.3mL
Answer:
8.7 g/ml
Explanation:
the formula for density is D = M/V
What is the temperature, in degrees Celsius, of a 10.5 grams sample of Neon gas confined to a volume of 2.50 L at a pressure of 1.00 atm.
Answer:
–215 °C
Explanation:
From the question given above, the following data were obtained:
Mass of Ne = 10.5 g
Volume (V) = 2.50 L
Pressure (P) = 1 atm
Temperature (T) =?
Next, we shall determine the number of mole present in 10.5 gof Neon, Ne. This can be obtained as follow:
Mass of Ne = 10.5 g
Molar mass of Ne = 20 g/mol
Mole of Ne =.?
Mole = mass /Molar mass
Mole of Ne = 10.5 / 20
Mole of Ne = 0.525 mole
Next, we shall determine the temperature of the sample of Neon, Ne. This can be obtained as follow:
Volume (V) = 2.50 L
Pressure (P) = 1 atm
Number of mole (n) = 0.525 mole
Gas constant (R) = 0.0821 atm.L/Kmol
Temperature (T) =?
PV = nRT
1 × 2.5 = 0.525 × 0.0821 × T
2.5 = 0.525 × 0.0821 × T
Divide both side by 0.525 × 0.0821
T = 2.5 / (0.525 × 0.0821)
T = 58 K
Finally, we shall convert 58 K to degree celsius (°C). This can be obtained as follow:
T(°C) = T(K) – 273
T(K) = 58 K
T(°C) = 58 – 273
T(°C) = –215 °C
Thus, the temperature of the sample of Neon gas is –215 °C.
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:
Right amount of gravity
the answer is: 9.80665
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.
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 elements are in H2CrO4
Answer:
3 elements
Explanation:
The elements are:
- Chromium
- Hydrogen
- Oxygen
What is the toto number of neutrons in an atom of 73 li
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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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
The process by which vesicles move substances out of a cell is
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
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:
Convert 3.4 moles of sodium oxalate into grams. Show all your work .
Answer:
m = 455,6 g
Explanation:
The mass can be determined by calculating the amount of substance times the molar mass:
m = n * M
To do this, you first have to calculate the molar mass of sodium oxalate. It is made up of the molar masses of the individual atoms. The molecular formula of sodium oxalate is:
[tex]Na_{2}C_{2}O_{4}[/tex]
M(Na) = 23 g/mol; M(C) = 12 g/mol; M(O) = 16 g/mol
M(Na2C2O4) = 2 * M(Na) + 2 * M(C) + 4 * M(O)
M(Na2C2O4) = 2 * 23 g/mol + 2 * 12 g/mol + 4 * 16 g/mol
M(Na2C2O4) = 134 g/mol
m = n * M
m = 3,4 mol * 134 g/mol
m = 455,6 g
The following is a list of common errors encountered in research laboratories. Categorize each as a determinate or an indeterminate error, and further categorize determinate errors as instrumental, operative, or methodic:
(a) An unknown being weighed is hygroscopic.
(b) One component of a mixture being analyzed quantitatively by gas chromatography reacts with the column packing.
(c) The tip of the pipet used in the analysis is broken.
(d) In measuring the same peak heights of a chromatogram, two technicians each report different heights.
Answer:
An unknown being weighed is hygroscopic. - operative error
One component of a mixture being analyzed quantitatively by gas chromatography reacts with the column packing. - methodic error
The tip of the pipet used in the analysis is broken. - instrumental error
In measuring the same peak heights of a chromatogram, two technicians each report different heights - operative error
Explanation:
In chemical analysis, operative errors are that largely introduced into the measurement because of variation of personal judgements of analysts. It is also a personal error that emanates solely due to the analyst.
A methodic error arises as a result of adopting defective experimental methods. For example, a column packing that reacts with a component of the mixture is used in the gas chromatography.
Instrument error refers to the error of a measuring instrument, for instance, the use of a pipette with a broken tip.
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.
Imagine there is technology that allows scientists to see all of the movement of molecules inside living things. A scientist points this machine at the stem of a vascular plant and sees glucose molecules being transported to various parts of the plant. The scientist is looking at the movement of molecules through
the xylem.
the phloem.
the roots.
the cuticle.
Answer: C
Explanation: I looked it up lol
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
Pls help I am confused my sister got me sweating
Answer:
Im pretty sure its B. is released by salivary glands.
Explanation:
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 of the following is an example of work: bowling or reading? How do you know?
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.
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:)
Write the equation for the dehydration of the CoCl2 hydrate
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)
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).
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
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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