Answer:
D
Explanation:
Friction plays an important part in many everyday processes. For instance, when two objects rub together, friction causes some of the energy of motion to be converted into heat.
Suggest why sodium wasn’t produced until the early 19th century.
Answer:
The reason is that sodium attaches itself very strongly to other elements. Its compounds are very difficult to break apartand also because it is so reactive.
Car manufacturers use radiation for which task?
A) Sealing Windows
B) Drying paint
C) Cleaning tires
D) Lubricating engines
THE CORRECT ANSWER IS B.
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Answer:
Indeed it is B, you are correct! :3
Explanation:
:3
Answer:
B. Drying paint
Car manufacturers use UV radiation to dry the paint o the vehicle. The high reflectivity of infrared radiation helps to keep the car interior cool. It also gives advantages over convection heating.
Explanation:
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Which statement about the atomic nucleus is correct?A.The nucleus is made of protons and has a negative charge.B.The nucleus is made of protons and neutrons and has a negative charge.C.The nucleus is made of electrons and has a negative charge.D.The nucleus is made of protons and neutrons and has a positive charge.
24. What is the total number of grams of potassium chloride needed to saturate exactly 300 grams of water at 10°C?
1) 70 2) 90 3) 80 4) 60
Answer:
That would be 90 grams
Explanation:
This should be right but please, please, please correct me if I'm worng because I dont want anyone to fail because of me. Have a great day luv <3
The answer is option B , 90 grams of potassium chloride(KCl) is needed to saturate exactly 300 grams of water at 10°C
How do you define Solubility ?The measure of the degree to which a substance gets dissolved in a solvent to become a solution.
The solubility of KCl in water at 10°C is 31.2gm/100gm of water .
So in 300 gm of water 3 * 31.2 gm = 93.6 gm
Using Significant Figures we can select option B i.e. 90 gm.
Hence Option B , 90 grams of potassium chloride is needed to saturate exactly 300 grams of water at 10°C
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A synthesis reaction takes place when carbon monoxide (CO) and hydrogen gas (H2) react to form methanol (CH3OH). How many grams of methanol are produced when 7.0 grams of carbon monoxide reacts with 2.5 grams of hydrogen gas?
Answer:
the answer is 8.0 g
Explanation:
The statement of mass (grams) of methanol is "0.008 g."
What is mass?A substance is something to do with mass that takes up space. The mass of a compound is the total amount of atoms present in grams that make up a molecule. The grams is the unit of mass.
The balanced equation comes out to be,
CO(g) + 2H2(g) → CH3OH(l)
In order to calculate the mass of methanol, initially the moles of the substance to be calculated from the given mass of CO and H2.
Gram to mole conversion,
[tex]=Grams\;*\;\frac{1\;mol}{grams}[/tex]
Moles of CO,
[tex]7.0\;g\;*\;\frac{1\;mol}{28.01\;g}\;=\;0.249\;mol\;CO[/tex]
Moles of H2
[tex]2.5\;g\;*\;\frac{1\;mol}{2.016\;g}\;=\;1.240\;mol\;O2[/tex]
Carbon monoxide is the limiting reagent which used up completely in the reaction.
Mass of methanol comes out to be,
[tex]0.249\;mol\;CO\;*\;\frac{1\;mol\;CH3OH}{\;mol\;CO}\;*\;\frac{1\;mol\;CH3OH}{32.04\;g\;CH3OH}\;=\;0.0077\;mol\;CH3OH[/tex]
≈ 0.008 mol CH3OH
Hence the correct answer is 0.008 mol.
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2 C4H10 + 13 O2 → 8CO2 + 10 H2O Which one is the Limiting Reactant
Answer:
It's a lot of calculation and it took me a bit of time
...
EXPLANATIONS
Consider the following combustion reaction: 2 C4H10 + 13 O2 ----> 8 CO2 + 10 H2O. 125 g or C4H10 react with 415 g of O2.
a.) Which mass of CO2 and H2O can be produced?
b.) Which substance is the limiting
a)
Molar mass of C4H10,
MM = 4*MM(C) + 10*MM(H)
= 4*12.01 + 10*1.008
= 58.12 g/mol
mass(C4H10)= 125.0 g
use:
number of mol of C4H10,
n = mass of C4H10/molar mass of C4H10
=(1.25*10^2 g)/(58.12 g/mol)
= 2.151 mol
Molar mass of O2 = 32 g/mol
mass(O2)= 415.0 g
use:
number of mol of O2,
n = mass of O2/molar mass of O2
=(4.15*10^2 g)/(32 g/mol)
= 12.97 mol
Balanced chemical equation is:
2 C4H10 + 13 O2 ---> 8 CO2 + 10 H2O
2 mol of C4H10 reacts with 13 mol of O2
for 2.151 mol of C4H10, 13.98 mol of O2 is required
But we have 12.97 mol of O2
so, O2 is limiting reagent
we will use O2 in further calculation
Molar mass of CO2,
MM = 1*MM(C) + 2*MM(O)
= 1*12.01 + 2*16.0
= 44.01 g/mol
According to balanced equation
mol of CO2 formed = (8/13)* moles of O2
= (8/13)*12.97
= 7.981 mol
use:
mass of CO2 = number of mol * molar mass
= 7.981*44.01
= 3.512*10^2 g
According to balanced equation
mol of H2O formed = (10/13)* moles of O2
= (10/13)*12.97
= 9.976 mol
use:
mass of H2O = number of mol * molar mass
= 9.976*18.02
= 1.798*10^2 g
Answer:
mass of CO2 = 3.51*10^2 g
mass of H20 = 1.80*10^2 g
b)
O2 is limiting reagent
A compound is found to contain 29.67 % sulfur and 70.31 % fluorine by mass.
To answer the question, enter the elements in the order presented above.
QUESTION 1:
The empirical formula for this compound is
The number of electrons in the valence shell of aluminum is
Answer: It has 13 electrons total and and 3 in the valance shell.
Explanation: Aluminum
For number 2 I need help with balancing equations and list the type of reaction plz and thank you
Answer:
Cd(NO3)2 + FeCl3 = CdCl2 + Fe(NO3)2
is an impossible equation to balance as this reaction will simply not occur and it will not work either ways
did your teacher make this ?
Which of the following characterizes a reaction at equilibrium?
A. The forward reaction stops, and the backward reaction starts.
B. The forward and backward reactions are equal.
C. The forward and backward reactions stop happening.
D. The reactants are changed into products.
SUBMIT
B. The forwards and backwards motions are equal
At chemical equilibrium,the forward and backward reactions are equal and opposite.
What is chemical equilibrium?Chemical equilibrium is defined as the condition which arises during the course of a reversible chemical reaction with no net change in amount of reactants and products.A reversible chemical reaction is the one wherein the products as soon as they are formed react together to produce back the reactants.
At equilibrium, the two opposing reactions which take place take place at equal rates and there is no net change in amount of the substances which are involved in the chemical reaction.At equilibrium, the reaction is considered to be complete . Conditions which are required for equilibrium are given by quantitative formulation.
Factors which affect chemical equilibrium are change in concentration , change in pressure and temperature and presence of catalyst.
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What is true about equinox? A.Day and night are equal in length. B. Shadows in the afternoon are longest. C. Nights are longest. D. Days are shortest.
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Which statement best describes the use of a chemical indicator in a titration?
A. It must be measured to the nearest 0.01 mL.
B. It must be colored in the acid solution.
C. It must measure pH directly at all pH values.
D. It must change color near the equivalence point.
The statement best describes the use of a chemical indicator in a titration is it must change color near the equivalence point.
What is a chemical indicator?A chemical indicator is any substance that shows a chemical change by color or other things.
In titration, phenolphthalein is used as an indicator in the titration of an acid or base.
Other chemical indicators are methyl yellow, litmus paper, and pH indicator.
Thus, the correct option is D. It must change color near the equivalence point.
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__Zn + __HCl --> __ZnCl2 + __H2
If 26.22 Liters of Hydrogen gas are produced, how many moles of Hydrochloric acid were reacted?
Answer:
1. The balanced equation:
Zn + 2HCl —> ZnCl₂ + H₂
The coefficients are: 1, 2, 1, 1
2. 2.34 moles of HCl
Explanation:
1. The balanced equation
__Zn + __HCl —> __ZnCl₂ + __H₂
There are 2 atoms of H on the right side and 1 atom on the left side
It can be balance by writing 2 before HCl as shown below:
Zn + 2HCl —> ZnCl₂ + H₂
Now the equation is balanced.
The coefficients are: 1, 2, 1, 1
2. Determination of the number of mole of HCl that reacted.
NOTE: 1 mole of H₂ = 22.4 L at STP.
Zn + 2HCl —> ZnCl₂ + H₂
From the balanced equation above,
2 moles of HCl reacted to produce 1 mole (i.e 22.4 L) of H₂.
Finally, we shall determine the number of mole of HCl needed to produce 26.22 L of H₂. This can be obtained as follow:
From the balanced equation above,
2 moles of HCl reacted to produce 22.4 L of H₂.
Therefore, Xmol of HCl will react to produce 26.22 L of H₂ i.e
Xmol of HCl = (2 × 26.22)/22.4
Xmol of HCl = 2.34 moles
Thus, 2.34 moles of HCl is needed for the reaction.
Which one of the following atoms has the largest radius?
Sr, Rb, K, Ca, Y
Answer: Rb (rubidium) has a radius of 290 pm, making it have the largest of the 5 elements listed.
Explanation:
Alcohol is used as a source of fuel for some automobiles. The standard molar enthalpy of formation of ethanol C2H5OH(l) is -277.6 kJ/mol. For the balanced reaction equation of ethanol use:
C2H5OH(l) + 3O2 --> 2CO2 + 3H2O.
Ethanol is a liquid, but all the other chemicals in this reaction are gases. What is the enthalpy change of this reaction in kJ/mol?
Answer:
[tex]\Delta _rH=-1,234.8kJ/mol[/tex]
Explanation:
Hello!
In this case, according to the given chemical reaction, it is possible to calculate the enthalpy change of the reaction via:
[tex]\Delta _rH=2\Delta _fH_{CO_2}+3\Delta _fH_{H_2O}-\Delta _fH_{C_2H_5OH}[/tex]
Since the enthalpy of formation of oxygen is 0. Thus, given the enthalpies of formation of gaseous carbon dioxide and water, we obtain:
[tex]\Delta _rH=2(-393.5kJ/mol)+3(-241.8kJ/mol)-(-277.6kJ/mol)\\\\\Delta _rH=-1,234.8kJ/mol[/tex]
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10. Which best explains why the total mass of the product(s) would be less than the total weight of the
reactant(s) after a chemical reaction?
А
A physical change occurred.
B
Atoms involved in the reaction lost mass.
с
Precipitates were created in the new solution.
D
Gases were released to the atmosphere.
Answer:
D. Gases were released to the atmosphere
Explanation:
In accordance to the law of conservation of mass, the total amount of reactants must equate the total amount of products at the end of the reaction because matter can not be lost or created. However, certain changes like gas evolution, formation of precipitate etc. indicates the occurrence of a chemical reaction.
In a chemical reaction, the total mass of the product(s) would be less than the total weight of the reactant(s) because GASES, which constituted part of the mass of the reaction, WERE RELEASED INTO THE ATMOSPHERE. However, if the mass of the gas released can be accounted for, the amount of reactants and products must balance.
Benzene is a minor component of gasoline. The standard molar enthalpy of formation of benzene C7H16(l) is 48.95 kJ/mol. For the balanced reaction equation of benzene use:
C6H6(l) + 7.5O2 --> 6CO2 + 3H2O.
Benzene is a liquid, but all the other chemicals in this reaction are gases. What is the enthalpy change of this reaction in kJ/mol?
Answer:
-3135.47 kJ/mol
Explanation:
Step 1: Write the balanced equation
C₆H₆(l) + 7.5 O₂(g) ⇒ 6 CO₂(g) + 3 H₂O(g)
Step 2: Calculate the standard enthalpy change of the reaction (ΔH°r)
We will use the following expression.
ΔH°r = ∑np × ΔH°f(p) - ∑nr × ΔH°f(r)
where,
n: moles
ΔH°f: standard enthalpies of formation
p: products
r: reactants
ΔH°r = 6 mol × ΔH°f(CO₂(g)) + 3 mol × ΔH°f(H₂O(g)) - 1 mol × ΔH°f(C₆H₆(l)) - 7.5 mol × ΔH°f(O₂(g))
ΔH°r = 6 mol × (-393.51 kJ/mol) + 3 mol × (-241.82 kJ/mol) - 1 mol × (48.95 kJ/mol) - 7.5 mol × 0 kJ/mol
ΔH°r = -3135.47 kJ
Since this enthalpy change is for 1 mole of C₆H₆(l), we can express it as -3135.47 kJ/mol.
A paracetamol tablet was crushed and an excess of HCl 25cm³ of 1.0mol was added. the result of the solution was titrate against 0.5mol of NaOH. calculate the mass of CaCO3 in the paracetamol.
Answer:
1.35g of CaCO₃ are in the paracetamol
Explanation:
Assuming the volume of the 0.5mol NaOH was 23cm³
The CaCO₃ of paracetamol reacts with HCl as follows:
CaCO₃ + 2HCl → CO₂ + H₂O + CaCl₂
When an excess of HCl is added and titrated, we can find the moles of HCl that react = Moles CaCO₃ based on the second reaction:
NaOH + HCl → H₂O + NaCl
Moles added of NaOH:
23cm³ = 0.023L * (0.5mol / L) = 0.0115 moles NaOH = Moles HCl in excess
Moles of HCl:
25cm³ = 0.025L * (1.0mol / L) = 0.025 moles HCl
The moles of HCl that reacted = Moles CaCO₃ are:
0.025 moles - 0.115 moles = 0.0135 moles CaCO₃
The mass of CaCO₃ -Molar mass: 100.09g/mol- is:
0.0135 moles CaCO₃ * (100.09g/mol) =
1.35g of CaCO₃ are in the paracetamolThe elements Beryllium (Be), Magnesium (Mg), Calcium (Ca) and Strontium (Sr) are all what?
answer : alkaline earth metals ..
Help and ill love you forever
Answer:
11 N to the right
Explanation:
the net force would be 24 N - 13 N, which is 11 N. Since 24 is the larger number, it will go in the direction of the 24 force
How many moles of O are in 11.6 mol Fe(NO3)3?
Express your answer in moles to three significant figures.
Answer:
Why might the expression "1 mole of nitrogen" be confusing? ... WebAssign will check your answer for the correct number of significant ... Calculate the moles of O atoms in 8.18 g of Mg(NO3)2. ... If the molar mass of hemoglobin is 6.8 104 g/mol, how many Fe2+ ions are ... (_) C7H16(l) + 11 O2(g) 7 CO2(g) + 8 H2O(g)
Explanation:
Explain why this substance is formed?
5.14 x 1023 ions NaCl to Moles
Answer:
2 moles
Explanation:
For a mole NaCi, we have a mole of sodium ion and a mole of chloride.
Part 1: Fill in the blanks below to state Newton’s three laws of motion:
Newton’s First Law: All objects will remain at _____, or will continue to move at a constant _____ in the same ____ unless acted upon by an unbalanced _____. This property is called _____.
Newton’s Second Law: Unbalanced forces cause an object to ______.
Newton’s Third Law: Every action produces an equal and opposite _____. When one object exerts a force on another object, the second object pushes back with the same amount of _____.
Answer:
all objects will remain at rest, or will continue to move at a constant speed in the same velocity unless acted upon by an unbalanced force. This property is called interia
Explanation:
The radius of a spherical aluminum atom is 140 picometers. How many aluminum atoms could be lined up across a length of 27.9 cm.
Answer:
9.96 × 10⁸
Explanation:
Step 1: Calculate the diameter of 1 aluminum atom
The diameter of a sphere is 2 times the radius.
d = 2 × 140 pm = 280 pm
Step 2: Convert "d" to m
We will use the conversion factor 1 m = 10¹² pm.
280 pm × 1 m/10¹² pm = 2.80 × 10⁻¹⁰ m
Step 3: Convert the total length (L) to m
We will use the conversion factor 1 m = 100 cm.
27.9 cm × 1 m/100 cm = 0.279 m
Step 4: Calculate the number of atoms of aluminum required
We will use the following expression.
L/d = 0.279 m/2.80 × 10⁻¹⁰ m = 9.96 × 10⁸
an empty relative density bottle weights 20g. the bottle weights 40g when filled with petrol and 60g when filled with water. determine the density of the petrol.( density of water=1000kg/m³)
Answer:
500 Kg/m³
Explanation:
From the question given above, the following data were obtained:
Mass of empty bottle = 20 g
Mass of bottle + petrol = 40 g
Mass of bottle + water = 60 g
Density of water = 1000 Kg/m³
Density of petrol =?
Next, we shall determine the mass of water. This can be obtained as follow:
Mass of empty bottle = 20 g
Mass of bottle + water = 60 g
Mass of water =?
Mass of water = (Mass of bottle + water) – (Mass of empty bottle)
Mass of water = 60 – 20
Mass of water = 40 g
Converting 40 g to Kg, we have:
1000 g = 1 Kg
Therefore,
40 g = 40 × 1 Kg / 1000 g
40 g = 0.04 Kg
Next, we shall determine the volume of the bottle by calculating the volume of water. This can be obtained as follow:
Mass of water = 0.04 Kg
Density of water = 1000 Kg/m³
Volume of water =?
Density = mass / volume
1000 = 0.04 / volume
Cross multiply
1000 × volume = 0.04
Divide both side by 1000
Volume of water = 0.04 / 1000
Volume of water = 4×10¯⁵ m³
Thus, the volume of the bottle is 4×10¯⁵ m³
Next, we shall determine the mass of the petrol. This can be obtained as follow:
Mass of empty bottle = 20 g
Mass of bottle + petrol = 40 g
Mass of petrol =?
Mass of petrol = (Mass of bottle + petrol ) – (Mass of empty bottle)
Mass of petrol = 40 – 20
Mass of petrol = 20 g
Converting 20 g to Kg, we have:
1000 g = 1 Kg
Therefore,
20 g = 20 × 1 Kg / 1000 g
20 g = 0.02 Kg
Finally, we shall determine the density of the petrol. This can be obtained as follow:
Mass of petrol = 0.02 Kg
Volume of petrol = 4×10¯⁵ m³
Density of petrol =?
Density = mass / volume
Density of petrol = 0.02 / 4×10¯⁵
Density of petrol = 500 Kg/m³
if the temperature of 20.0 L of gas were increased to twice the initial value, while the pressure is held constant what would be the volume of the gas at the new temperature
Answer:
40 L
Explanation:
From the question given above, the following data were obtained:
Initial volume (V₁) = 20 L
Initial temperature (T₁) = T
Final temperature (T₂) = 2T
Pressure (P) = constant
Final volume (V₂) =?
The new (i.e final) volume of the gas can be obtained as follow:
V₁/T₁ = V₂/T₂
20/T = V₂/2T
Cross multiply
T × V₂ = 20 × 2T
T × V₂ = 40T
Divide both side by T
V₂ = 40T /T
V₂ = 40 L
Therefore, the new volume of the gas is 40 L
Which of the following are true about both the sun and the stars? Choose the three correct answers.
A.
Both are visible during the day in summer.
B.
Both move across the sky from east to west.
C.
Both change positions in the sky due to Earth's revolution.
D.
Both are visible at night in winter.
E.
Both appear in different positions in the sky due to Earth's rotation.
F.
Both move from north to south in the sky.
Answer:
D, F
Explanation:
find the hybridization of carbon in acetone
how does berylium apply to real life
☁️ Answer ☁️
Safety features like air bags and fire suppression sprinkler systems are maintained in a state of constant readiness, saving lives thanks to the reliability and strength of beryllium.
❤️
Beryllium is a part of many of the things you rely on each day, including cellular phones, kitchen and laundry appliances, home temperature controls, MP3 players, desktop and portable computers, and your car.
❤️
Beryllium and beryllium–containing materials are utilized extensively in many of the high tech devices (including satellites and imaging systems) used by the military to keep our citizens safe at home and abroad.
❤️
Used in high-resolution medical imaging and laser equipment, beryllium is a valuable part of the medical field’s arsenal to help you fight disease and stay healthy.
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