Answer:
Gain 2, and become negatively charged
Explanation:
A full valence shell, thus stablilized, has 8 electrons, and so it would need two more, and when atoms gain electrons, they become negatively charged because there are now more electrons than protons (and so, when they lose electrons, they become positively charged). Hope this helps! :)
When heat is applied to 80 grams of CaCO3, it yields 39 grams of B. Determine the percentage of the yield.
The question is incomplete, the complete question is:
When heat is applied to 80 grams of CaCO3, it yields 39 grams of CaO Determine the percentage of the yield.
CaCO3→CaO + CO2
Answer: The % yield of the product is 87.05 %
Explanation:
The number of moles is defined as the ratio of the mass of a substance to its molar mass.
The equation used is:
[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}[/tex] ......(1)
We are given:
Given mass of [tex]CaCO_3[/tex] = 80 g
Molar mass of [tex]CaCO_3[/tex] = 100 g/mol
Putting values in equation 1, we get:
[tex]\text{Moles of }CaCO_3=\frac{80g}{100g/mol}=0.8mol[/tex]
For the given chemical reaction:
[tex]CaCO_3\rightarrow CaO+CO_2[/tex]
By stoichiometry of the reaction:
If 1 mole of [tex]CaCO_3[/tex] produces 1 mole of CaO
So, 0.8 moles of [tex]CaCO_3[/tex] will produce = [tex]\frac{1}{1}\times 0.8=0.8mol[/tex] of CaO
We know, molar mass of [tex]CaO[/tex] = 56 g/mol
Putting values in above equation, we get:
[tex]\text{Mass of CaO}=(0.8mol\times 56g/mol)=44.8g[/tex]
The percent yield of a reaction is calculated by using an equation:
[tex]\% \text{yield}=\frac{\text{Actual value}}{\text{Theoretical value}}\times 100[/tex] ......(2)
Given values:
Actual value of the product = 39 g
Theoretical value of the product = 44.8 g
Plugging values in equation 2:
[tex]\% \text{yield}=\frac{39 g}{44.8g}\times 100\\\\\% \text{yield}=87.05\%[/tex]
Hence, the % yield of the product is 87.05 %
Which statement best summarizes what happens during cellular respiration?
A. Energy in food is released and stored in ATP molecules.
B. Energy from sunlight moves through a food web.
C. Chemical energy is converted to kinetic energy.
D. Solar energy is converted and stored in chemical bonds.
Answer:
A
Explanation:
B is for photosynthesis, C and D are just energy conversions, A is all about producing energy and stored as Adenosine Triphosphate(ATP) which is respiration
An atom or ion has 42 neutrons
, 36 protons, and 36 electrons. Identify the element symbol, and determine the mass number and charge for this atom or ion
Answer:
Krypton
Explaination:
Element-Krypton
Symbol-Kr
Mass-83.8amu
charge-none
How much energy would be produced from the reaction of 2.40 moles hydrogen with 3.95 moles chlorine? ___ H2 + ___ Cl2 ___ HCl ΔH = -554 kJ
Answer:
How much energy would be produced from the reaction of 2.40 moles hydrogen with 3.95 moles chlorine?
[tex]H_2 + Cl_2 -> 2HCl , deltaH = -554 kJ[/tex]
Explanation:
Given,
2.40 moles hydrogen reacts with 3.95 moles chlorine.
From the balanced chemical equation,
1mol. of H2 reacts with 1mol. of Cl2
then,
2.40mol. of H2 reacts with ----?mol of Cl2
[tex]=>2.40 mol. H2 * \frac{1mol. Cl2}{1mol. H2} \\=2.40 mol. Cl2[/tex]
So, the remaining moles of Cl2 is in excess.
The limiting reagent is--- H2.
1mol. of H2 releases --- 554kJ of energy
then,
2.40mol of H2 releases ---- ?
[tex]=>2.40mol * \frac{554kJ}{1 mol.} \\=1329.6kJ[/tex]
Answer is: deltaH =-1329.6kJ
name the gas which is formed when coal is heated in the absense of air
Answer:
Coke
Explanation:
A solid fuel formed by heating coal in the absence of air is coke. Coke is black colored, tough porous substance. It is pure carbon.
What is the equilibrium expression for the reaction below?
2Na(s) + 02) Na2O2,(s)
Answer:
[tex]{ \tt{k _{c} = \frac{[Na_{2} O _{2} ]}{[Na] {}^{2} [O _{2} ]} }}[/tex]
Roundup, a herbicide manufactured by Monsanto, has the formula C3H8NO5P. How many moles of molecules are there in a 647.3-g sample of Roundup?
I got the answer 2.305 x 10^24 but for some reason it’s not working. Is it the wrong one?
Answer:
3.830177515 moles
Explanation:
You have :
647.3 g of RoundupMolar mass of Round up which is equal to 169 g.moland the formula: n=m/MTherefore: n=647.3/169
=3.830177515 moles
How does dissolving a salt molecule in water make its atoms ionize?
Answer:
It's take 1 and a half hours
Explanation:
Ugbdunvisrtg
What is the volume of 0.200 mol of an ideal gas at 200. kPa and 400. K?
Use P V equals n R T. and R equals 8.314 StartFraction L times kilopascals over moles time K EndFraction..
3.3256 Liters
See the image I have shared to you above
Answer:
B. 7.2k
Explanation:
took the test ;)
which is an example of the force of attraction between two obects that have mass?
Answer:
gravity
Explanation:
Gravity is an example of the force of attraction between two objects that have mass.
A TV has a standby current of 0.05 amperes. The voltage going through the TV is 120 volts. Determine the power consumption while the TV is in standby.
Answer:
6 Watts
Explanation:
From the question given above, the following data were obtained:
Current (I) = 0.05 A
Voltage (V) = 120 V
Power (P) =?
Electrical power is defined by the following equation
The power consumption while the TV is in standby can be obtained as follow:
Power (P) = Current (I) × Voltage (V)
P = IV
With the above formula, we can obtain the power consumption while the TV is in standby. This can be obtained as follow:
Current (I) = 0.05 A
Voltage (V) = 120 V
Power (P) =?
P = IV
P = 0.05 × 120
P = 6 Watts
Therefore, the power consumption while the TV is in standby is 6 Watts.
3. Which best describes the definition for the atomic mass of an element?
A. It is a ratio based on the mass of the carbon-12 atom.
B. It is the sum of the protons. And neutrons in one atom of the element.
C. It is twice the number of protons in one atom of the element.
D. It is a weighted average of the masses of an element’s isotopes.
Answer:
B
Explanation:
Its the sum of the protons and neutrons.
How many grams of HNO3 is needed to make 1.5 L of a 3 M solution of HNO3? Show work
Answer:
283.5g
Explanation:
first u need to know the molar mass of hno3 which is 63.01
the g=1.5×3×63.01
g= 283.5
PLEASE HELP ASAP
You have 3 beakers sitting in front of you for a lab, but you forgot to label the beakers. You
do not remember which chemical you put into which beaker, and they are all colourless
solutions. You know that you had hydrogen chloride (HCI), lithium sulfate (Li,SO.), and
Describe two diagnostic tests, including expected results that you could use to identify the
three solutions and allow you to label your beakers
Answer:
put a salt into the beakers
An atom has an atomic number of 19 and mass number of 39 how many electrons and protons does it have?
Answer:
19 protons, 20 neutrons and 18 electrons.
Explanation:
The atomic number gives the number of protons 19
p = 19
The atomic mass is the sum of the protons and neutrons
p + n = 39 p = 19
put p into the equation and solve for n the neutrons.
19 + n = 39
Subtract 19 from both sides
19 − 19 + n = 39 − 19
n = 20
The number of electrons equals the number of protons in a neutral atom. The positive charge equals the negative charge. The negative charge is the number of electrons. This ion has a charge of +1. So solve for the negative charge.
− 19 + 1 = − 18
The negative charge is -18 so
e = 18
How does increasing temperature increase the number of reactions?
A. It increases the length of time the molecules are together.
B. It increases the collisions that have enough energy to react.
C. It makes the orientation of the molecules not important.
D. It lowers the amount of energy needed for a reaction to occur.
Answer:D. it lowers the amount of evergy needed for a reaction to occur.
Explanation:
a p e x
The concept Arrhenius equation is used here to determine the factor which increases the number of reactions. As the temperature increases, It increases the collisions that have enough energy to react. The correct option is B.
What is Arrhenius equation?An equation which represents the relationship between the activation energy and rate of the reaction is known as the Arrhenius equation. According to this concept, lower the activation energy of a reaction, the higher its rate will be.
The equation is:
[tex]k = A . e^{-} ^{E_{a} } / RT[/tex]
k - Rate constant
A - Frequency factor
Eₐ - Activation energy
R - Gas constant
T - Temperature
When the temperature increases, the energy and speed of the molecules increases which in turn increases the number of effective collisions. If greater the value of frequency of collisions, then value of 'k' will be higher and greater is the number of reactions.
Thus the correct option is B.
To know more about rate of a reaction, visit;
https://brainly.com/question/30546888
#SPJ7
state and explain the trends in the atomic radius and ionization energy for elements Li to Cs.
Explanation:
ionisation energy decrease down the group as the atomic radius increases. Nuclear charge increases. Number of shell increases so the electron will experience more shielding so it would be easier for the atom to loss electron.
give few property of PET
Answer:
Transparency to visible light and microwaves. Very good resistance to ageing, wear and heat. Lightweight, impact and shatter resistant. Good gas and moisture barrier properties
Explanation:
Answer:
Your Welcome! :)
Explanation:
What are the Characteristics of Polyethylene terephthalate (PETE or PET)?
Chemical Resistance: PET does not react with water or food which is one of the reasons it is used for consumable packaging.
Strength to Weight Ratio: PET is very strong for its lightweight.
Shatterproof: PET will not break or fracture.
A teacher brings in a cup of iced water and asks students to discuss if the system is exothermic or endothermic . Aida states the system is exothermic , while Alexander states the system is endothermic .
Answer:
C
Explanation:
In thermodynamics, a exothermic system looses heat to the surroundings while an endothermic system absorbs heat from the surroundings.
A system is a part the universe marked off by a specified boundary. The contents of the cup constitutes the system in this case.
The region of space outside the system is called the surroundings. Hence everything outside the cup constitutes the surroundings.
What mass of Na2SO4is needed to make 2.5 L of 2.0 Msolution? (Na = 23 g; S = 32 g; O = 16 g)
a.356 g
b.284 g
c.710 g
d.178 g
Answer:
mass (g) needed = 710.2 grams Na₂SO₄(s)
Explanation:
Needed is 2.5 Liters of 2.0M Na₂SO₄; formula wt Na₂SO₄ = 142.04g/mol.
mass (grams) of Na₂SO₄(s) = Molarity needed x Volume needed in Liters x Formula Wt of solute
mass (grams) of Na₂SO₄(s) = (2.5L)(2.0M)(142.04g/mol) = 710.2 grams Na₂SO₄(s)
Mixing: Transfer 710.4 grams Na₂SO₄ into mixing vessel and add water-solvent up to but not to exceed 2.5 Liters total volume. Mix until dissolved.
Gives 2.5 Liters of 2.0M Na₂SO₄(aq) solution.
6. La electronegatividad es una propiedad periódica que incide en un enlace químico verdadero o falso? Si es falso, porque?
Answer:
Verdadero.
Explanation:
¡Hola!
En este caso, dado que las propiedades periódicas nos hablan de un comportamiento específico sobre los elementos en la tabla periódica, resulta primeramente necesario recordar que la electornegatividad nos dice que tan fuerte es un elemento para atraer electrones de valencia de otros elementos.
De este modo, inferimos que es verdadero, ya que de hecho la electronegatividad nos define el tipo de enlace, basado en la diferencia de electronegatividades de los elementos enlazados, de acuerdo con la imagen adjunta.
Saludos!
Help me with this science question on the middle one..
CHEM FINAL PLEASE HELP
This is?
alkene
aromatic hydrocarbon
alkyne
alkane
Answer:
It is alkyne
Explanation:
Which one is it ?! (Hurry)
The student is now told that the four solids, in no particular order, are aluminum chloride (AlCl3AlCl3), sugar (C6H12O6C6H12O6), butanoic acid (C3H7COOHC3H7COOH), and potassium bromide (KBrKBr), and potassium bromide (KBr). Assuming that conductivity is correlated to the number of ions in solution, rank the four substances based on how well a 0.20 M solution in water will conduct electricity. Rank from most conductive to least conductive. To rank items as equivalent, overlap them.
Answer:
aluminum chloride> potassium bromide> butanoic acid> sugar
Explanation:
Conductivity has to do with the ability of a solid to dissolve in solution leading to the formation of mobile ions which are the charge carriers in solution.
Strong electrolytes produce more ions in solution hence they have a higher conductivity.
Aluminum chloride produces four particles in solution hence it has the highest conductivity followed by potassium bromide which produces two particles in solution. Butanoic acid is a weak electrolyte which dissociates only to a small extent while sugar is a nonelectrolyte, it does not dissociate at all in solution.
Solve for a, b, c, AND d
d
C
84°
930
970
b
13. If a reaction is endothermic,
a) The temperature increases
b) It takes more energy to break the bonds of the reactants than is released when the bonds in
the products are formed
c) More energy is released when the bonds in the products are formed than is used to break
the bonds in the reactants
d) The same amount of energy is used to break the bonds of the reactants as is
released when the bonds in the products are formed
Answer:
Endothermic reactions are reactions that require external energy, usually in the form of heat, for the reaction to proceed. In order to melt the ice cube, heat is required, so the process is endothermic. Endothermic reactionIn an endothermic reaction, the products are higher in energy than the reactants.
Explanation:
Calculate the change in thermal energy when 2kg of water is heated from 20°C to 80°C.
Answer:
504000 J
Explanation:
Applying,
Δq = cm(Δt)............. Equation 1
Where Δq = change in thermal energy, c = specific heat capacity of water, m = mass of water, Δt = change in temperature.
From the question,
Given: m = 2 kg, Δt = 80-20 = 60°C
Constant; c = 4200 J/kg.°C
Substitute these values into equation 1
Δq = 2(4200)(60)
Δq = 504000 J
Hence the thermal energy is 504000 J
write a word equation for the reaction between dilute hydrochloric acid and magnesium
Some one help me with these real quick I need help with questions 4 & 6.!
Answer:
4 is chemical and 6 is a
Explanation:
hope this helps