Answer:
32.42
Explanation:
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The enthalpy of combustion of octane is -5470 kJ/mol. Octane (formulae C8H18) was used to heat some water in a copper can. The amount of octane used up was 0.1 g. The amount of water in the can was 100 cm3 . a) Find the moles of octane which was used up. (Show calculations)
Answer: 0.0009 moles of octane were used up.
Explanation:
To calculate the moles :
[tex]\text{Moles of solute}=\frac{\text{given mass}}{\text{Molar Mass}}[/tex]
Given mass of octane = 0.1 g
Molar mass of octane = 11.23 g/mol
Putting in the values we get:
[tex]\text{Moles of octane}=\frac{0.1g}{114.23g/mol}=0.0009moles[/tex]
Thus 0.0009 moles of octane were used up.
Help!! 8th grade science (for a grade)
Answer:
I DONT GET IT IETHER
Explanation:
DONT GET IT
Which of the following is an example of an exothermic reaction?
A. Thermal decomposition
B. Ammonium nitrate and water C. Photosynthesis
D. Respiration
Exothermic reactions release heat when the reactants produce products. The process of respiration is an exothermic reaction as it releases heat. Thus, option D is correct.
What is an exothermic reaction?An exothermic is a type of reaction that involves the release of heat during the reaction through product formation. The respiration reaction is exothermic as it involves the breakdown of oxygen and glucose into energy.
Thermal decomposition is an endothermic reaction as it requires energy for completion. Similarly, photosynthesis and reaction between ammonium nitrate and water are endothermic reactions as they also require energy from the external source.
Therefore, respiration is an exothermic reaction.
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Identify each type of reaction shown below:
Answer:
See explanation
Explanation:
1. Decomposition= when one compound or substance is separated into 2 elements.
2. Single displacement: b is switched with c
3. double displacement: when 2 reactants form 2 different products
Neon is located in the last group of the periodic table. How many valence electrons
Answer:
8 valence electrons
Explanation:
Neon is a noble gas, and all noble gases have 8 valence electrons. The same goes for its group; all elements in the last group of the periodic table have a full valence shell--8 electrons.
list down some examples of solutions that we need to prepare/make in the form of unsaturated and saturated solution
Answer:
1)Carbonated water is saturated with carbon, hence it gives off carbon through bubbles.
2)Adding sugar to water until it no longer dissolves creates a saturated solution.
3)Continuing to dissolve salt in water until it will no longer dissolve creates a saturated solution.
An unsaturated tea and sugar solution would be one into which you could add more sugar and have the sugar still dissolve
Calculate the molarity of a solution prepared by dissolving 2.50 mol of KCl into 2.00 L of solution.
________ M
Answer:
1.25 M
Explanation:
The molarity is found dividing the moles of solute by the litres of solution.
2.50 mol ÷ 2 L = 1.25 M
The concentration terms are molality, normality and mole fraction. Molarity can be used to find out the ionic strength of any solution. Therefore, the molarity of a solution prepared by dissolving 2.50mol of KCl into 2.00 L of solution is 1.25 M.
What is molarity?Molarity can be calculated by dividing number of moles of solute by volume of solution in liter. Molarity is affected by temperature. Its unit is mole/liter. It measure the concentration of any solute in a solution.
Mathematically,
Molarity= number of moles of solute/volume of solution in liter
number of moles of solute KCl= 2.50 mol
volume of solution in litre = 2.00 L
substituting all the given values in the above equation, we get
Molarity= 2.50 mol ÷ 2 L
Molarity = 1.25 M
Therefore, the molarity of a solution prepared by dissolving 2.50mol of KCl into 2.00 L of solution is 1.25 M.
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What are Oxygens important uses (and why)?
Answer:
Common uses of oxygen include production of steel, plastics and textiles, brazing, welding and cutting of steels and other metals, rocket propellant, oxygen therapy, and life support systems in aircraft, submarines, spaceflight and diving.
Explanation:
Oxygen is used to degrade hydrocarbon compounds, which are broken apart by heating them. This is used to create combustion that usually liberates water and carbon dioxide, but can also produce the hydrocarbons acetylene, propylene and ethylene. Oxygen is used in sewage-treatment and water-purification plants.
(HELP FAST)Which of the following always changes when a substance undergoes a
chemical change?
Question 2
Name the following compound:
N_Bro
O Tetranitrogen Nonabromide
O Quadranitrogen Nonabromide
O Nitrogen Bromide
Answer:
Tetranitrogen Nanobromide
Croquet balls must have a mass of 0.50 kg. A red croquet ball, moving at 10
m/s, strikes an at-rest green croquet ball head-on. The red ball continues
moving at 1.5 m/s after it hits the green ball. What is the final speed of the
green ball?
O A. 5 m/s
B. 8.5 m/s
C. 1.5 m/s
O D. 15 m/s
SUS
The final speed of the green ball : 8.5 m/s
Further explanationGiven
mass of Croquet ball = 0.5 kg
v₁= 10 m/s
v₁'= 1.5 m/s
Required
the final speed
Solution
The law of conservation of momentum
m₁v₁ + m₂v₂ = m₁v₁ '+ m₂v₂' (1=red croquet ball, 2=green croquet ball)
v₂=0 (at rest)
Input the value :
[tex]\tt 0.5\times 10+0.5\times 0=0.5\times 1.5+0.5\times v_2'\\\\5=0.75+0.5v_2\\\\4.25=0.5v_2\rightarrow v_2=8.5~m/s[/tex]
When a liquid is cooled, the kinetic energy if the particles A. Decrease B. Increases C. Remains the same. The force of attraction between the particles A. Decrease B. Increases C. Remains the same , the space between the particles A. Decrease B. Increases C. Remains the same
Answer:
(A.) Kinetic energy decreases(B.) Force of attraction increases(C.) Space between particles remains the sameExplanation:
Kinetic energy is the energy in motion. Cooling if liquid would cause decreased temperature and hence slow down the oscillation of the particles.
Likewise, increased heat reduces the force of attraction between said particles, which allowed for their free movement. So the cooling would have opposite effect.
Finally, the space between the particles would remain the same as it was originally, as their force of attraction is increased in the cooling process, they would take the form they are held in.
I hope this was helpful and concise?
what are the coefficients that will balance the skeleton equation
Answer:
When the following equation is balanced, what is the coefficient for HCl? Mg(s) + HCl(aq) -> MgCl2(aq) + H2(g) . 2. What are the coefficients that will balance the skeleton equation below? AlCl3 + NaOH -> Al(OH)3 + NaCl.
NEED HELP!!!
Which word best describes a form of energy associated with molecules in motion and heat?
Thermal energy
Kinetic energy
Vaporization
Condensation
The particles are in a fixed position. What state of matter is this?
Answer:
The state of matter is solid
Explanation:
how is mechanical energy related to potential and kinetic energy
Answer:
Mechanical energy is the energy that is possessed by an object due to its motion or due to its position. Mechanical energy can be either kinetic energy (energy of motion) or potential energy (stored energy of position). A moving car possesses mechanical energy due to its motion (kinetic energy).
Explanation:
What mass of Ca(OH)2 would you need to make 300.0mL of a 1.2M solution of Ca(OH)2
Answer:
is there a picture.....????
What unit is mass generally measured in
Answer:
kilograms
Explanation:
hope this helps, pls mark brainliest :D
Answer:kilogram
Explanation:
I got the smarts
NEED HELP?!! Whats the answer
Metals make what type of ions
Answer: Metal atoms lose the electron/ electrons in their highest energy level and become positively charged ions.
Answer:
Cations
Explanation:
Cations (positively-charged ions) and anions (negatively-charged ions) are formed when a metal loses electrons, and a nonmetal gains those electrons. The electrostatic attraction between the positives and negatives brings the particles together and creates an ionic compound, such as sodium chloride.
Key Terms:
➡An anion can be defined as an atom or molecule that is negatively charged. ➡A cation can be defined as an atom or molecule that is positively charged. ➡They have an opposite electrical charge, therefore they get attracted to each other.
when the white part is on the left the moon is.??
Answer:
Last Quarter also called Third Quarter.
Explanation:
Guys please help me
What happens when the number of electrons and protons inside of or atenie equel?
Answer:
When the number of electrons does not equal the number of protons, the atom is ionized and then they are no longer atoms, they are known as ion(s).
can someone explain this to me?
Answer:it says how to make an atom stable like ion if the atom is metal then it will lose the atom to be full outer shell and if it is non metal it will gain.
second thing there is also covalent bond which share electron with other atomto be full outer shell
hope this help!!
Which substance is the precipitate?
Answer:
In chemistry, a precipitate is an insoluble solid that emerges from a liquid solution. The emergence of the insoluble solid from solution is called precipitation. Often the precipitate emerges as a suspension. Precipitates can form when two soluble salts react in solution to form one or more insoluble products.
Explanation: Hope this helps! :>
A student adds different amounts of ice to four samples of water and records the change in temperature after 30 minutes. What is the independent variable in this investigation?
Answer:
Amount of ice
Explanation:
When we talk about independent variable, we mean that variable in an experiment that is manipulated and its effect on the dependent variable is measured.
In this case, the amount of ice in each water sample determines the temperature of each sample. Hence the amount of ice is the independent variable.
Answer:
ice cubes added
Explanation:
An atom is
a. the smallest unit of matter that maintains its chemical identity.
b.the smallest unit of a compound.
c.always made of carbon.
d.smaller than an electron
Answer:
A. The smallest unit of matter.
Explanation:
Atoms make up everything and are the smallest unit of all units.
A base used in baking cake is
Answer:
sodium bicarbonate, potassium bicarbonate and ammonium bicarbonate are the most commonly used bases.
Help? i need to finish my assignment :>
Answer:
B 2
Explanation:
I checked it and it’s right hope this helps!!
) Calculate the Gibbs energy change for the formation of propane at 298K.Given that ∆H for propane is -103.85KJ/mol.∆S for the reaction is - 269.74KJ/mol.
Answer:
ΔG = 80,278.67 J/mol
Explanation:
Given:
∆H = - 103.85KJ/mol
∆S = - 269.74KJ/mol
T= 298 K
The Gibbs energy change (ΔG) is calculated as follows:
ΔG = ΔH - TΔS
ΔG = (-103.85KJ/mol)-298K(- 269.74KJ/mol)
ΔG = (-103.85KJ/mol) - (-80,382.52 J/mol)
ΔG = 80,278.67 J/mol
An element has atomic number 10 and an atomic mass of 20. How many neutrons are in the atom of this element?
OA.
10
OB.
20
O C.
30
D. 0
O E. 200
10
subtract the atomic mass from the atomic number