Calculate the number of moles of MgO if the mass of MgO (magnesium oxide) is 50 g?
Please help... I will mark the answer with brainlist...
Answer:
1.24mol
Explanation:
m(MgO)=50g
molar mass=40.30g/mol (i search in google coz dosnt have book)
n=mass/molar mass
=50/40.30
=1.24mol
where are people mostly exposed to chemicals?
Answer:
people are mostly exposed to chemicals through their nose, mouth, eyes, and ears
Explanation:
they are the easiest way for anything, bad or good, to enter the body because people touch their face alot.
This might not answer what you were looking for but the other answer covered it pretty well so I thought I'd give you another angle to the question!
Hope this helps!!
A 2.575 g piece of gold (specific heat = 0.129 J/g°C) at a temperature of 75°C is placed into cold water at 10°C. If the gold loses 10.0 J of energy, what is its final
temperature in the water? Enter your answer to the
nearest whole number of °C.
Answer:
The final temperature of the mixture is 44.9°C
Explanation:
Mass of the substance (gold) = 2.575g
Specific heat capacity of gold = 0.129J/g°C
Initial temperature (T1) = 75°C
Final temperature (T2) = ?
Energy lost = 10J
Heat energy(Q) = MC∇T
Q = heat energy (in this case lost)
M = mass of the substance
C = specific heat capacity of the substance
∇T = change in temperature of the substance = (T2 - T1)
Q = MC∇T
Q = MC(T2 - T1)
-10 = 2.575 × 0.129 × (T2 - 75) energy is -ve because it was energy lost.
-10 = 0.3321 × (T2 - 75)
-10 = 0.3321T2 - 24.9075
Collect like terms
0.3321T2 = 24.9075 - 10
0.3321T2 = 14.9075
T2 = 14.9075 / 0.3321
T2 = 44.88
T2 = 44.9°C
The final temperature of the mixture is 44.9°C
pls help as soon I will give brainlist
Answer:
1) Conditions necessary for rusting are:
a) Presence of atmospheric oxygen or air
b)Presence of water or moisture
2) For protecting the iron gate, we can paint it because the paint will coat it and protect it from atmospheric oxygen and water.
3) Magnesium, Carbon and Oxygen (MgCO₃)
An elements mass number is made up of the number of ____ in the nucleus.
protons and neutrons
electrons and neutrons
protons and electrons
atoms and molecules
Answer:
The answer is protons and nuetrons
Explanation:
NEED HELP
What is the temperature in kelvin of a gas if it is allowed to expand from 1.50 L to 4.50 L? The initial temperature is 10.0°C and pressure is constant throughout the change. Which equation should you use?
Answer:
Explanation:
V1/T1 =V2/T2 at constnant pressure
Answer:
c
Explanation:
How will you test for the gas which is liberated when hcl reacts with an active metal ?
During a reaction, the enthalpy of the reactants and the products are not equal. What does this result in?
A. None of these
B. Absorption or release of energy
C. Change in chemical composition
D. Spin of electrons is reversed
The spin of electrons is reversed. Hence, option D is correct.
What is enthalpy?Enthalpy is the sum of the internal energy. and pressure times volume.
During a reaction, the enthalpy of the reactants and the products are not equal which means the spin of electrons is reversed.
Hence, option D is correct.
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⚠️SOMEONE PLEASE HELP⚠️
Which describes two phases in dynamic equilibrium?
O A. Molecules in one phase continually change to the other.
O B. The total number of molecules must be equal in each phase.
O C. Molecules do not change from one phase to the other.
O D. The total number of molecules in each phase stays constant.
Answer:
The total number of molecules in each phase stays constant
Explanation:
i just took the test and got it right.
In the dynamic equilibrium between 2 phases, the total number of molecules in each phase stays constant (Option D).
When does dynamic equilibrium occur?Dynamic equilibrium occurs when the direct and reverse rates are equal and the concentrations remain constant over time.
Which describes two phases in dynamic equilibrium?
A. Molecules in one phase continually change to the other. NO. Molecules in both phases continually change.B. The total number of molecules must be equal in each phase. NO. This is not necessarily true.C. Molecules do not change from one phase to the other. NO. This would be a static equilibrium.D. The total number of molecules in each phase stays constant. YES. Since the forward and reverse rates are equal.In the dynamic equilibrium between 2 phases, the total number of molecules in each phase stays constant (Option D).
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The pressure inside of a sealed tube if you raise the temperature go ______..
Answer:
The pressure will increase due ot expnasion of gasses in a closed sealed tube tube .
Explanation:
Answer:
The pressure inside of a sealed tube will increase if the temperature is raised.
Explanation:
When the temperature of the gas inside the sealed tube is raised, the particles within that tube will start to become faster and faster. Because they are going faster they collide with the sides of the tube faster, therefore increasing the pressure inside the sealed tube.
Hope this helps!
The energy from 0.015 moles of octane was used to heat 250 grams of water. The temperature of the water rose from 293.0 K to 371.2 K. What is the enthalpy of combustion of octane? The specific heat capacity of water is 4.18 J/K g.
A. -5448 kJ/mol
B. 1226 kJ/mol
C. -1226 kJ/mol
D. 293.25 kJ/mol
Answer:
A.) -5448 kJ/mol
Explanation:
I got it correct on founders edtell
Attempt 1 of 1
Which of the following is most likely to have a crystalline structure?
wood
rubber
glass
quartz
Answer: Quartz
Explanation: I looked it up ;)
This beaker contains an aqueous solution of copper II nitrate.
Write the chemical formula for the solute chemical that is dissolved):
Write the chemical formula for the solvent( liquid that does the dissolving)
Answer:
See the answer below
Explanation:
Aqueous solution of copper II nitrate contains solute of copper II nitrate dissolved in water. The equation for the reaction is as below:
[tex]Cu(NO_3)_2 (s)[/tex] + [tex]H_2O (l)[/tex] --> [tex]Cu(NO_3)_2 (aq)[/tex]
Hence, the solute chemical is copper II nitrate while the solvent is water.
Chemical formula of copper II nitrate - [tex]Cu(NO_3)_2[/tex]
Chemical formula of water - [tex]H_2O[/tex]
The chemical formula is different from the empirical formula in
A) H2O2
B) CO2
C) CO.
OD) H20.
Answer:
A) H2O2
Explanation:
Hydrogen peroxide is written as H2O2, which is the chemical formula of the compound, but this can be simplified. Since both H and O have the subscript of 2, they can be simplified to 1, so the empirical formula for H2O2 would be just H and O together (Brainly won't let me say the empirical form because it has the same spelling as a swear word). Thus, the empirical formula and chemical formula are different.
In the case of the other options, they are all in their simplest form and cannot be simplified further, so they are already in their empirical form, so both the chemical form and empirical form are the same.
The diagram shows the setup of an experiment. The observations of the experiment are listed in the table below the diagram. A beaker filled three-fourths with a liquid labeled colorless silver nitrate solution is shown. A small strip is shown inside the beaker. The strip is labeled copper strip. The title of the image is Experimental Setup. Experimental Observations Observation Description 1 Copper strip became thinner 2 Gray particles were deposited on the edge of the strip Which of the following is the correct explanation for one of the given observations? (4 points) Observation 2 is a result of nitrate ions moving into the solution. Observation 2 is a result of silver ions moving into the solution. Observation 1 is a result of copper atoms losing two electrons. Observation 1 is a result of silver atoms losing one electron.
Answer:
The answer is Observation 1 is a result of copper atoms losing two electrons.
Explanation:
The electrons result in the color change of the copper strip, causing the gray particles to join onto the metal.
Answer:
C
Explanation:
Observation 1 is a result of the copper atoms losing two electrons. It came out as the right answer.
What is the frequency of radiation emitted by a photon of light if the energy released during its transition to ground state is 3.611 × 10-15 joules? (Planck's constant is 6.626 × 10-34 joule seconds)
Answer:
5.449 x 10¹⁸ Hz
Explanation:
Energy (E) =Frequency (F) x Plancks constant (h)
F= 3.611x10⁻¹⁵J / 6.626 x 10⁻³⁴ Js⁻¹
F =5.449 x10¹⁸ s⁻¹ or 5.449 x 10¹⁸ Hz
WILL MARK BRAINLIEST IF GOOD EXPLANATION...
Ethyl acetate is a sweet-smelling solvent used in varnishes and fingernail polish remover. It is produced industrially by heating acetic acid and ethanol
together in the presence of sulfuric acid, which is added to speed up the
reaction. The ethyl acetate is distilled off as it is formed. The equation for the
process is as follows.
CH3COOH + CH3CH2OH --> CH3COOCH2CH3 + H2O
Determine the percentage yield in the following cases:
a. 68.3 g of ethyl acetate should be produced but only 43.9 g is recovered.
b. 0.0419 mol of ethyl acetate is produced but 0.0722 mol is expected. (Hint:
Percentage yield can also be calculated by dividing the actual yield in moles
by the theoretical yield in moles.)
c. 4.29 mol of ethanol is reacted with excess acetic acid, but only 2.98 mol of
ethyl acetate is produced.
d. A mixture of 0.58 mol ethanol and 0.82 mol acetic acid is reacted and 0.46
mol ethyl acetate is produced. (Hint: What is the limiting reactant?)
Answer:
a) 64.27%
b) 58%
c) ethanol is the limiting reactant
d) ethanol is the limiting reactant
Explanation:
We have to note that the expected yield is the theoretical yield while the actual mass or amount of product formed is the actual yield.
a) theoretical yield=68.3g
Actual yield= 43.9 g
Percentage yield= 43.9/68.3 ×100
Percentage yield= 64.27%
b) theoretical yield= 0.0722 moles
Actual yield = 0.0419
Percentage yield= 0.0419/0.0722 × 100
Percentage yield= 58%
c) note that the limiting reactant yields the least number of moles of product
Ethanol will be the limiting reactant since it is not present in excess.
d) from the reaction equation;
1 mole of acetic acid produces 1 mole of ethyl acetate
0.58 moles of ethanol produces 0.58 moles of ethyl acetate
1 mole of acetic acid yields 1 mole of ethyl acetate
Hence 0.82 moles of acetic acid yields 0.82 moles of ethyl acetate
Hence ethanol is the limiting reactant.
Give some examples of how ultraviolet rays can be used
Answer:
One of the most common ways of producing UV light is passing an electric current through vaporized mercury or some other gas. This type of lamp is commonly used in tanning booths and for disinfecting surfaces. The lamps are also used in black lights that cause fluorescent paints and dyes to glow.Explanation:
Which phrase describes a feature of a Mercator projection? is least commonly used sizes most features to scale presents longitude lines as parallel shows most accurately near the prime meridian
QUICK
Answer:
presents longitude lines as parallel
Explanation:
The Mercator projection shows longitude lines as parallel, hence greatly distorts sizes and distances near the poles. A useful feature is that a course of constant bearing shows as a straight line.
Answer:
C.) presents longitude lines as parallel
Explanation:
Took it on E2020
at what temperature would 2.10moles of N2 gas have a pressure of 1.25atm and fill a 25.0 L tank
Answer:
[tex]\large \boxed{\text{-92 $^{\circ}$C}}[/tex]
Explanation:
We can use the Ideal Gas Law and solve for T.
pV = nRT
Data
p = 1.25 atm
V = 25.0 L
n = 2.10 mol
R = 0.082 06 L·atm·K⁻¹mol⁻¹
Calculations
1. Temperature in kelvins
[tex]\begin{array} {rcl}pV & = & nRT\\\text{1.25 atm} \times \text{25.0 L} & = & \rm\text{2.10 mol} \times 0.08206 \text{ L}\cdot\text{atm}\cdot\text{K}^{-1}\text{mol}^{-1} \times T\\31.25&=&0.09847T\text{ K}^{-1}\\T& = &\dfrac{31.25}{\text{0.098 47 K}^{-1}}\\\\& = &\text{181 K}\end{array}[/tex]
2. Temperature in degrees Celsius
[tex]\begin{array} {rcl}T & = & (181 - 273.15) \, ^{\circ}\text{C}\\& = & -92 \, ^{\circ}\text{C}\\\end{array}\\\text{The temperature of the gas is $\large \boxed{\mathbf{-92 \, ^{\circ}}\textbf{C}}$}[/tex]
How would you separate pure dry cleaning solvent from waste dry cleaning solvent containing dirt that dissolves in the solvent from clothes
Answer:
fddff s
Explanation:
v c dggbgzfx
In an ecosystem, why can only one species fill an ecological niche?
Answer:
Explanation:es porque las especies con nichos idénticos tienen las mismas necesidades, lo que significa que competirían exactamente por los mismos recursos.
Which process occurs at each link in a food chain?
Some Energy is released into the environment as heat
Explanation:
Level 3- How is tooth decay related to pH?How can it be prevented?
Answer:
A lower pH of the mouth creates bad bacteria that eventually lead to decay of the tooth.
It can be prevented by avoiding food that causes acidity.
Explanation:
Tooth decay is caused by the pH level in the mouth dropping below 5.5, meaning it is acidic. It can be prevented by brushing your teeth as toothpaste is an alkali which will neutralise the pH level in your mouth.
Hope this helps
A 500ml bottle contains 2.50 moles of gas. What is the new volume when the number of miles is increased 5.00 moles?
Answer:
The new volume is 1,000ml
Explanation:
Mathematically, we know that the number of moles per ml(volume) should be constant irrespective of the increase.
Initially, we have a volume of 500 ml and number of moles of 2.5 moles
The ratio of the number of moles to the volume is 2.5/500 = 0.005 mole/ml
Now, this is expected to remain the same even if we have an increment.
let’s call the new volume x
0.005 mol/ml = 5 moles/x ml
x = 5/0.005 = 1,000 ml
In which orbitals would the valence electrons for carbon (C) be placed?
Answer: orbitals supernumerary
Explanation:
Answer:
both S orbital and p orbitals
Explanation:
took the exam got the question right.
A weather balloon calibrated at 0.00 °C to have a volume of 20.0 L has
what volume at -40.0 °C assuming pressure is held constant?
Answer:
17.1 Liters
Explanation:
It's a gas law question (more specifically a Charles's Law question). Formula is V1/T1 = V2/T2. You're given V1 and T1 and T2. However, in order to use the equation, temperature needs to be in Kelvins (by subtracting the degrees C from 273) for the numbers to work (among other reasons, the 0 degrees C will always give you an answer of zero or undefined). Placing all temps in kelvins makes the answers come out right. So 20L/273K = xL/233K gives you the answer when you cross-multiply.
Considering the Charles's law, a weather balloon calibrated at 0.00 °C to have a volume of 20.0 L has 17.07 L at -40.0 °C, assuming pressure is held constant.
The gas laws are a set of chemical and physical laws that allow determining the behavior of gases in a closed system. The parameters evaluated in these laws are pressure, volume, temperature and moles.
Charles's law is one of the gas laws. It relates the volume and the temperature of a certain quantity of ideal gas, kept at a constant pressure.
This law states that, at constant pressure, the volume of a gas is directly proportional to its temperature. In other words, for a given sum of gas at constant pressure, as the temperature increases, the volume of the gas increases, and as the temperature decreases, the volume of the gas decreases.
Mathematically, Charles's law says that the quotient that exists between the volume and the temperature will always have the same value:
[tex]\frac{V}{T}=k[/tex]
Being an initial state 1 and a final state 2, it is true:
[tex]\frac{V1}{T1}=\frac{V2}{T2}[/tex]
In this case, you know:
V1= 20 LT1= 0 C=273 KV2= ?T2= -40 C= 233 KReplacing:
[tex]\frac{20 L}{273 K}=\frac{V2}{233 K}[/tex]
Solving:
[tex]V2=233 K x\frac{20 L}{273 K}[/tex]
V2=17.07 L
Finally, a weather balloon calibrated at 0.00 °C to have a volume of 20.0 L has 17.07 L at -40.0 °C, assuming pressure is held constant.
Learn more:
https://brainly.com/question/4147359?referrer=searchResultsThe density was of a solution of sulfuric acid is 1.285g/cm3 and it is 38.08% (by weight) acid. How many millimeters of the acid solution do you need to supply 125 grams of sulfuric acid?
Answer:
255.5cm³
Explanation:
A solution that is 38.08 % by weight has 38.08g of sulfuric acid per 100g of total solution. Thus, mass of solution you need to obtain 125g is:
125g H₂SO₄ × (100g solution / 38.08g H₂SO₄) = 328.3g of solution
As density of the solution is 1.285g / cm³, the volume of 328.3g is:
328.3g × (1cm³ / 1.285g) = 255.5cm³
50cm3 of sodium hydroxide solution was titrated against a solution of sulfuric acid. The concentration of the sodium hydroxide solution was 20g/dm3. Work out the concentration of the acid in grams per litre if it took 25cm3 of acid to completely neutralise the alkali. The relative molecular mass of sulfuric acid is 98.
Answer:
49 g/L is the concentration of the acid
Explanation:
Firstly, we proceed to write the equation of reaction.
2NaOH + H2SO4 ——-> Na2SO4 + 2H2O
We can see that 1 mole of the base reacted with two moles of the acid.
kindly note that dm^3 is same as liter
Firstly, we need to get the concentration of the reacted sulphuric acid in g/L
we use the simple titration equation below;
CaVa/CbVb = Na/Nb
From the question;
Ca = ?
Va = 25 cm^3
Cb = 20 g/L
we convert this to concentration in mol/L
Mathematically, that is concentration in g/L divided by molar mass in g/mole
molar mass of NaOH = 40 g/mol
so we have; 20g/L / 40 = 0.5 mol/L
Vb = 50 cm^3
Na = 1
Nb = 2
Where C represents concentrations, V volumes and N , number of moles
Now, substitute the values;
Ca * 25/0.5 * 50 = 1/2
25Ca/25 = 0.5
So Ca = 0.5 mol/L
Now to get the concentration of H2SO4 in g/L
What we do is to multiply the concentration in mol/L by molar mass in g/mol
That would be 0.5 * 98 = 49 g/L
The concentration of the acid in grams per litre is 49g/L
From the question,
We are to determine concentration of the sodium hydroxide solution.
First, we will write a balanced chemical equation for the reaction.
The balanced chemical equation for the reaction is
2NaOH + H₂SO₄ → Na₂SO₄ + 2H₂O
This means,
2 moles of NaOH is required to completely neutralize 1 mole of H₂SO₄
From the formula
[tex]\frac{C_{A}V_{A} }{C_{B}V_{B} }=\frac{n_{A} }{n_{B} }[/tex]
Where
[tex]C_{A}[/tex] is the concentration of acid
[tex]C_{B}[/tex] is the concentration of base
[tex]V_{A}[/tex] is the volume of acid
[tex]V_{B}[/tex] is the volume of base
[tex]n_{A}[/tex] is the mole ratio of acid
[tex]n_{B}[/tex] is the mole ratio of base
From the question
[tex]V_{A}= 25 \ cm^{3}[/tex]
[tex]C_{B} = 20 \ g/dm^{3}[/tex]
Convert this to mol/dm³
Molar mass of NaOH = 40 g/mol
Using the formula
[tex]Concentration\ in \ mol/dm^{3} =\frac{Concentration\ in \ g/dm^{3}}{Molar\ mass}[/tex]
∴ Concentration of the NaOH in mol/dm³ = [tex]\frac{20}{40}[/tex]
Concentration of the NaOH in mol/dm³ = 0.5 mol/dm³
∴ [tex]C_{B} = 0.5 \ mol/dm^{3}[/tex]
and
[tex]V_{B} = 50 \ cm^{3}[/tex]
From the balanced chemical equation
[tex]n_{A} = 1[/tex]
[tex]n_{B} = 2[/tex]
Putting the parameters into the formula, we get
[tex]\frac{C_{A} \times 25}{0.5 \times 50}= \frac{1}{2}[/tex]
Now, this becomes
[tex]2 \times 25 \times C_{A}=0.5 \times 50 \times 1[/tex]
Then, we get
[tex]50 C_{A} = 25[/tex]
∴ [tex]C_{A} = \frac{25}{50}[/tex]
[tex]C_{A} = 0.5 \ mol/dm^{3} = 0.5 \ mol/L[/tex]
Now, we will determine the concentration in g/L
From the formula,
Concentration in g/L = Concentration in mol/L × Molar mass
From the question,
Molar mass of sulfuric acid = 98
∴ Concentration of the acid in g/L = 0.5 × 98
Concentration of the acid in g/L = 49 g/L
Hence, the concentration of the acid in grams per litre is 49g/L
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How many moles of gas are contained in 22.41 liters at 101.325 kPa and 0ᴼC? (Note: use Ideal Gas Law, PV = nRT) a 2.5 mole b 1.5 mole c 1.0 mole d 2.0 mole
Answer:
Therefore, 1.00 mole of the gas is present in the container.
Explanation:
The following data were obtained from the question:
Volume (V) = 22.41L
Temperature (T) = 273K
Pressure (P) = 101.325 kPa
Gas constant (R) = 8.31 L.kPa/mol.K.
Number of mole (n) =...?
The number of mole of the gas in the container can obtained by applying the ideal gas equation as illustrated below:
PV = nRT
Divide both side by RT
n = PV /RT
n =101.325 x 22.41 / 8.31 x 273
n = 1.00 mole.
Therefore, 1.00 mole of the gas is present in the container.
Answer:
1 mole of gas is contained in 22.41 liters at 101.325 kPa and 0ᴼC
Explanation:
Ideal gases are a simplification of real gases that is done to study them more easily. It is considered to be formed by point particles, do not interact with each other and move randomly. It is also considered that the molecules of an ideal gas, in themselves, do not occupy any volume.
The pressure, P, the temperature, T, and the volume, V, of an ideal gas, are related by a simple formula called the ideal gas law:
P*V = n*R*T
where P is the gas pressure, V is the volume that occupies, T is its temperature, R is the ideal gas constant, and n is the number of moles of the gas.
In this case:
P= 101.325 kPa= 1 atmV= 22.41 Ln=?R= 0.082 [tex]\frac{atm*L}{mol*K}[/tex]T= 0°C= 273 °KReplacing:
1 atm*22.41 L=n* 0.082 [tex]\frac{atm*L}{mol*K}[/tex]*273 K
Solving:
[tex]n=\frac{1 atm*22.41 L}{0.082\frac{atm*L}{mol*K} *273 K}[/tex]
n=1 mole
1 mole of gas is contained in 22.41 liters at 101.325 kPa and 0ᴼC
