Answer:
jwjsjdjdhdvjeiejjrjrje
Burning a candle melts the wax, but also burns the wick. Explain how burning a candle involves both physical and chemical changes.
Answer:
Burning of the candle is both physical and chemical change. Burning of the candle melts the wax and hence physical state of wax has changed from solid to liquid.
Again the wax combines with the atmospheric oxygen and changes to carbon dioxide, heat and light.
Thus both the changes are accompanied by the burning of the candle.
Explanation:
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Enthalpy of
CH4(g) + 2NO2(g) -> N2(g) + CO2(g) + 2H2O(l)
Answer:
-177.9 kJ.
Explanation:
Use Hess's law. Ca(s) + CO2(g) + 1/2O2(g) → CaCO3(s) ΔH = -812.8 kJ 2Ca(s) + O2(g) → 2CaO(s) ΔH = -1269.8 kJ We need to get rid of the Ca and O2 in the equations, so we need to change the equations so that they're on both sides so they "cancel" out, similar to a system of equations. I changed the second equation. Ca(s) + CO2(g) + 1/2O2(g) → CaCO3(s) ΔH = -812.8 kJ 2CaO(s) → 2Ca(s) + O2(g) ΔH = +1269.8 kJ The sign changes in the second equation above since the reaction changed direction. Next, we need to multiply the first equation by two in order to get the coefficients of the Ca and O2 to match those in the second equation. We also multiply the enthalpy of the first equation by 2. 2Ca(s) + 2CO2(g) + O2(g) → 2CaCO3(s) ΔH = -1625.6 kJ 2CaO(s) → 2Ca(s) + O2(g) ΔH = +1269.8 kJ Now we add the two equations. The O2 and 2Ca "cancel" since they're on opposite sides of the arrow. Think of it more mathematically. We add the two enthalpies and get 2CaO(s) + 2CO2(g) → 2CaCO3(s) and ΔH = -355.8 kJ. Finally divide by two to get the given equation: CaO(s) + CO2(g) → CaCO3(s) and ΔH = -177.9 kJ.
HELP ME ASAPPP plsss
What statement best explains how life functions a unicellular organism are carried out?
Answer:
The structures in the cell work together to perform its life functions
Explanation:
Answer:
What statement best explains how life functions a unicellular organism are carried out?
Explanation:
How many molecules are in
6.0 moles of methane (CH4)?
Let's begin by setting up our equation.
What belongs in the green box?
6.0 moles CHA
A. 1 mole CH4
B. 6.02 x 1023 molecules CH4
PLEASEEEEEEEEEEEEE HELP You get 28 points
1. _____are muscles that you control, for example, your bicep.
2. ________muscles are muscles that you DO NOT consciously control, for example, your heart.
3. Tendons are _______ that connect muscles to joints.
How do plants respond to seasonal changes
Answer
Plants can respond to the change of season by losing their leaves, flowering, or breaking dormancy. Plants go through seasonal changes after detecting differences in day length.
Explanation:
what is the mass of 2.31 x 10^23 formula units of SrF2?
Mole measure the number of elementary entities of a given substance that are present in a given sample. Therefore, 40.51 g is the mass of 2.31x10²³ formula units of SrF[tex]_2[/tex].
What is mole?The SI unit of amount of substance in chemistry is mole. The mole is used to measure the quantity of amount of substance. It measure the number of elementary entities of a given substance that are present in a given sample.
Given number of atoms= 2.31x10²³atoms
we know one mole of any element contains 6.022×10²³ atoms which is also called Avogadro number
mole =given number of atoms ÷ 6.022×10²³(Avogadro number)
Substituting the values
mole= 2.31x10²³÷ 6.022×10²³
mole = 0.38 moles of SrF[tex]_2[/tex]
mass of SrF[tex]_2[/tex]= moles of SrF[tex]_2[/tex] × Molar mass of SrF[tex]_2[/tex]
mass of SrF[tex]_2[/tex]= 0.38 × 106.6184
mass of SrF[tex]_2[/tex] = 40.51 g
Therefore, 40.51 g is the mass of 2.31x10²³ formula units of SrF[tex]_2[/tex].
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Mass number symbol =
Answer:
A is the symbol of mass number.
Explanation:
→ Mass number (A) = Protons + Neutrons
It is the required formula. The symbol of the mass number is A.
Answer:
The letter A
Explanation:
Madison is heating two different liquids. For each liquid, she wants to compare the temperatures at which gas bubbles form, rise, and begin to escape. What physical property is Madison using to compare the liquids?Immersive Reader boiling point conductivity melting point solubility
Answer:
I think its boiling point conductivity
Answer: boiling point
Explanation:
Got it right
2LiBr Pb(NO3)
2 → PbBr2 2LiNO3
In addition to showing the ratio of atoms in a molecule, what else do the subscripts in a formula tell us?
Answer:
See explanation
Explanation:
Usually, when we write a chemical formula for any compound or other chemical specie, we use subscripts to;
Indicate the ratio of atoms of each element present in the compound or chemical specieShow the number of atoms of each element present in the compound or chemical specie.Hence, the subscripts written after chemical formulas have more than one function as described above.
In H2SO4 for instance, there are two hydrogen atoms, one sulphur atom and four oxygen atoms as shown in the chemical formula.
Numbers 15-21
HELP PLEASE!!
(06.05 LC)
Why is it important to maintain records of the procedures of an experiment?
points)
Multiple Choice
Question 1 (1 point) How many stars are in our solar system? A. About 20.000 B. About 300,000 C. One D. About 5,000
Answer:
C. one star
Explanation:
Of course our solar system has one unique star which is the sun while others have atleast two which are called binary solar
When a small piece of sodium metal is dropped into a beaker of water, hydrogen gas (H2) and a solution of sodium hydroxide (NaOH) are products. The solution becomes warm.
Answer:
The reaction is exothermic as the solution becomes warm.
Explanation:
Hello there!
In this case according to the described reaction between sodium metal and water, we can write up the chemical equation whereas the products turn out to be sodium hydroxide and hydrogen gas:
[tex]2Na+2H_2O\rightarrow 2NaOH+H_2[/tex]
Moreover, these reactions are known to be highly exothermic, for that reason the solution becomes warm as the reaction releases heat as it goes to completion.
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Which of the following is another term for eruptions of gas on the sun's surface?
A. nuclear fusion
B. sunspots
C. coronas
D. solar flares
Answer:
D
Explanation:
What is the activation energy of this reaction?
50 kJ
100 kJ
150 kJ
200 kJ
Answer:
50 kJ
Explanation:
Activation energy is between the energy of reactants and the peak of the curve.
200 kJ - 150 kJ = 50 kJ
The correct answer is 50kJ
What is Activation Energy?The least amount of energy required to activate atoms or molecules to a state in which they can undergo a chemical reaction is known as Activation Energy.What is the activation energy of this reaction? The activation energy of this reaction is the energy released between reactants and productsIn graph the activation energy is difference between Reactants and the peakTherefore, 200-150=50KJ
Hence 50KJ is activation energy
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1. A student wants to find how many calories are in a peanut. Describe in detailed complete sentences how they can test this using a can with
150g of water and a thermometer.
Answer: 65 cal
Explanation: they have to find the weight of the peanuts on a scale and per grams. Then put them in water . You should be able to get the calories
List two kinds of text structure
Answer:
Chronological: discussing things in order.
Cause and effect: explaining a cause and its results.
the formula equation of Acetylene + oxygen ----> carbon dioxide + water
Answer:
The final balanced equation is : 2C2H2+5O2→4CO2+2H2O.
A bicycle tire holds 1.50 L of air at 5atm and 20.0 °C. How many moles of air is this?
If the average mass of air is 29.0 g/mol, what is the mass of air in the tire?
Answer:
9.05 g
Explanation:
PV=nRT
Use the ideal gas equation. Substitute values.
P = 5 atm
V = 1.50 L
n = ?
R (gas constant) = 0.08206 L-atm/mol-K
T = 20.0°C
*Always convert °C to K.
T = 20.0° + 273 = 293K
Substitute values.
(5 atm)(1.50 L) = n(0.08206 L-atm/mol-K)(293K)
n = (5 atm)(1.50 L) / (0.08206 L-atm/mol-K)(293K)
n = 0.3119335... mol
Convert to grams with the given average mass of air.
0.3119335... mol x (29.0 g/1 mol) = 9.05 g
What happened when you mixed the two substances together? The substances changed into different substances. The substances changed into different substances. The substances did not change into different substances. The substances did not change into different substances. I am not sure if the substances changed into different substances. I am not sure if the substances changed into different substances.
Answer:
is this a poem or something?
someone help me on these two 2
Answer:
Question 4 is- Solubility
Question 5 is- Suspension
Hopes this helps >:D
One advantage to using nuclear power is —
it produces no air pollution
it is hard to store and dispose of the waste
the expense of constructing nuclear reactors
the threat of an accident
Answer:
it produces no air pollution
26) Is the constant speed that a falling object eventually reaches when air 3 points
resistance builds up and prevents further acceleration *
Speed of Gravity
Terminal Velocity
Acceleration
Drag speed
Answer:
terminal velcity
Explanation:
The energy needed to overcome intermolecular forces is called?
Answer:
vaporization.
Explanation:
In a 0.879 M potassium permanganate (KMnO4) aqueous solution, what is the SOLUTE?
Answer:
Potassium Permanganate
Explanation:
A solution is defined as the mixture of two or more substances. The substance that is in big proportion is called as Solvent, the substance that is in low amount is called as Solute.
In an aqueous solution, the solvent is the water. As the aqueous solution is 0.879M KMnO4, the solute is:
Potassium Permanganatewhat is the chemical equation for
3fe(s)+4h2o(l)→fe3o4(s)+4h2(g)
Answer:
3fe s )+ 4h2o G )= fe3o4 s )+ 4h2 G
Explanation: 3Fe(s) + 4H2O(g) → Fe3O4(s) + 4H2(g) (i) Iron metal is getting oxidised. (ii) Water is getting reduced. (iii) Water is acting as reducing agent.
Explanation:
i make a search
Which of the following pictures is a chemical change, and which is a
physical change? Explain in the boxes next to the picture.
Plz explain
Answer:
left is chemical because its chemicals, and right is physical because the ice cream is melting and thats physical
Explanation: