Answer:
En el grupo de los no metales se incluyen los halógenos (flúor, cloro, bromo, yodo, astato y téneso), que tienen 7 electrones en su última capa de valencia y los gases nobles (helio, neón, argón, kriptón, xenón, radón), que tienen 8 electrones en su última capa (excepto el helio, que tiene 2).
Explanation:
halógenos
Answer:
1,4
Explanation:
Which of the following could be classified as a molecular element?
Question 1 options:
krypton
lithium
nitrogen
calcium
All four are classified as molecular elements.
Answer:
calcium is the correct answer to the question
How many ATOMS of boron are present in 3.61 grams of boron trifluoride ?
Answer:
To determine the number of atoms of Boron that are present within 3.61 grams of Boron Trifluoride, it would be best to convert the grams to moles of the compound and then after that use the Avogadro's number to determine the number of molecules and then use the 1 to 3 ratio to determine the total number of Boron atoms.
the liquid left after crystallization is
Answer:
The liquid left after crystallization is called Residue
WHAT IS PHOTOSYNTHESIS??
Answer:
the process by which green plants and some other organisms use sunlight to synthesize nutrients from carbon dioxide and water. Photosynthesis in plants generally involves the green pigment chlorophyll and generates oxygen as a by-product.
Answer:
the process by which green plants and some other organisms use sunlight to synthesize nutrients from carbon dioxide and water. Photosynthesis in plants generally involves the green pigment chlorophyll and generates oxygen as a by-product.
What is good conductor of electricity???
Answer:
Metals , silver and copper which allows to pass the electricity through it is called good conductor of electricity .
hope it is helpful to you ☺️
I need help what is the answer for question 1
Answer: where is the deephorizon slice at ?
Explanation:
What are the reasons for Small Island States are particularly concerned with reducing carbon dioxide emissions
Answer:
- Because it could lead to rise in sea levels which could cause heavy floods in the Small Island States and thus destroy their economies.
Explanation:
The reason is that too much carbon dioxide emissions trapped in the atmosphere can cause global worming which includes climate change and rise in sea levels.
Now, due to the fact that we know islands are lands surrounded by water, a rise in sea level of by as small as 1 metre could be very dangerous to these small islands in that they could cause them to become flooded and thus cause harm to lives and properties thereby damaging their economies.
All light waves can be described in terms of their speed, frequency, and_____
Which of these is an example of a chemical change?
Answer:
D. Burning a peice of wood
Explanation:
Because when you burn wood a chemical reaction happenes between the flames and the wood making the wood into ashes.
Hope this helps you :)
The dissolving salt in water is an an example of a chemical change. The correct option is A.
A chemical change, also known as a chemical reaction, is the production of new substances with changing chemical compositions and characteristics.
In water, sodium chloride dissociates into Na+ ions and Cl- ions, which may be described as a chemical process.
The ionic connections between the atoms are broken as salt dissolves. Because the reactant (sodium chloride or NaCl) varies from the products (sodium and chloride ions), a chemical reaction takes place.
Thus, the correct option is A.
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Interms of air molecules, what gives a balloon its shape when air is blown into it
Answer: Because when you blow air /gas into a balloon you fill it with air particles ,so they more you blow u blow in more air particles so they tend to collide with each other ,so as they hit the walls of the balloons pressure is exerted ,so the pressure keeps the balloon inflated with its shape
a sample of unknown material weighs 500 n in air and 200 n when immesersed in alcholol with a specfic gravity of 0.7 what is the mass density
Answer: The mass density is 1166.36 [tex]kg/m^{3}[/tex].
Explanation:
Given: Weight of sample in air [tex](F_{air})[/tex] = 500 N
Weight of sample in alcohol [tex](F_{alc})[/tex] = 200 N
Specific gravity = 0.7 = [tex]0.7 \times 1000 = 700 kg/m^{3}[/tex]
Formula used to calculate Buoyant force is as follows.
[tex]F_{B} = F_{air} - F_{alc}\\= 500 - 200 \\= 300 N[/tex]
Hence, volume of the material is calculated as follows.
[tex]V = \frac{F_{B}}{\rho \times g}[/tex]
where,
[tex]F_{B}[/tex] = Buoyant force
[tex]\rho[/tex] = specific gravity
g = acceleration due to gravity = 9.81
Substitute the values into above formula.
[tex]V = \frac{F_{B}}{\rho \times g}\\= \frac{300}{700 \times 9.81}\\= \frac{300}{6867}\\= 0.0437 m^{3}[/tex]
Now, mass of the material is calculated as follows.
[tex]mass = \frac{F_{air}}{g}\\= \frac{500 N}{9.81}\\= 50.97 kg[/tex]
Therefore, density of the material or mass density is as follows.
[tex]Density = \frac{mass}{volume}\\= \frac{50.97 kg}{0.0437 m^{3}}\\= 1166.36 kg/m^{3}[/tex]
Thus, we can conclude that the mass density is 1166.36 [tex]kg/m^{3}[/tex].
I need the answer to this asap!! please explain
Answer:
See explanation
Explanation:
Calcium carbide reacts with water to yield acetylene gas and calcium hydroxide as follows;
CaC2(s)+2H2O(g)⇋Ca(OH)2(s)+C2H2(g)
This now shows us that the equation as written in the question is wrong. Since the equation for the reaction of calcium carbide and water as shown in the question is wrong, the equation can not be balanced.
Complete the sentence
The Earth’s earliest atmosphere contained large amounts of carbon dioxide. The percentage of carbon dioxide in the Earth’s atmosphere today is ___
A) Less than 1%
B) 5%
C) 21%
D) 78%
Answer:
A) Less than 1%
Explanation:
The answer is approximately 0.04%
what is the formulas for Calcium Chloride,Aluminium Sulphate and Sodium hydroxide. *
Answer:
Explanation:
Why is there a star * behind the question.
CaCl2
Al2(SO4)3
NaOH
Calculate the height of a column of ethanol (C2H5OH) that would be supported by atmospheric pressure. The density of ethanol is 0.789 g/cm3.
Answer:
The height of a column of ethanol is 13.1m
Explanation:
we begin by converting the density to SI unit= 0.789g/cm3* 1kg * [tex]100^{3}[/tex]* [tex]cm^{3}[/tex]
cm * 1000g * [tex]1^{3}m^{3}[/tex]
= 789kg/m3
converting pressure to SI unit= 1 atm =101325 Pa
hence P= hdg
g= 9.81 m/s2
making h the subject of the formula
h= P/dg
h= 101325Pa/ 789kg/m3 * 9.81 m/s2
h= 13.1m
Among the given solutions of potassium permanganate (KMnO4), which one has the highest concentration of water in it?
Answer: Solution D has the highest concentration of all.
Explanation:
The formula used to calculate molarity:
[tex]\text{Molarity of solution}=\frac{\text{Moles of solute}\times 1000}{\text{Volume of solution (mL)}}[/tex] .....(1)
For A:Molarity of permanganate solution = 0.1 M
Volume of solution = [tex]100 cm^3=100mL[/tex] (Conversion factor: [tex]1mL=1cm^3[/tex])
Putting values in equation 1, we get:
[tex]0.1=\frac{\text{Moles of permanganate solution}\times 1000}{100}\\\\\text{Moles of permanganate solution}=\frac{100\times 0.1}{1000}=0.01mol[/tex]
For B:Molarity of permanganate solution = 0.01 M
Volume of solution = [tex]100 cm^3=100mL[/tex]
Putting values in equation 1, we get:
[tex]0.01=\frac{\text{Moles of permanganate solution}\times 1000}{100}\\\\\text{Moles of permanganate solution}=\frac{100\times 0.01}{1000}=0.001mol[/tex]
For C:Molarity of permanganate solution = 2 M
Volume of solution = [tex]100 cm^3=100mL[/tex]
Putting values in equation 1, we get:
[tex]2=\frac{\text{Moles of permanganate solution}\times 1000}{100}\\\\\text{Moles of permanganate solution}=\frac{100\times 2}{1000}=0.2mol[/tex]
For D:Molarity of permanganate solution = 2.5 M
Volume of solution = [tex]100 cm^3=100mL[/tex]
Putting values in equation 1, we get:
[tex]2.5=\frac{\text{Moles of permanganate solution}\times 1000}{100}\\\\\text{Moles of permanganate solution}=\frac{100\times 2.5}{1000}=0.25mol[/tex]
The solution having the highest number of moles will have the highest concentration for the same volume.
Thus, solution D has the highest concentration of all.
Crystals of sodium chloride were prepared by the following method.
1 25.0 cm3
of dilute hydrochloric acid was accurately measured into a conical flask.
2 Aqueous sodium hydroxide was added until the solution was neutral. The volume of
sodium hydroxide added was measured.
3 The solution was evaporated and the crystals washed with approximately 15 cm3
of water.
Which row shows the pieces of apparatus used to measure the 25.0 cm3
of hydrochloric acid, the
volume of aqueous sodium hydroxide and the 15 cm3
of water?
Answer: the answer is C
IF U MIGHT NEED AN EXPLANATION FEEL FREE TO COMMENT
The laboratory equipment like the burette, pipette, and measuring cylinders are used in process of titration process. The solution of NaOH is added by the burette. Thus, option C is correct.
What is titration?Titration has been the analytical technique that uses the known and measured quantity of the solution to estimate the volume of another solution with an unknown volume and known molar concentration.
The laboratory equipment like burette, pipette, and measuring cylinders are used in measuring the volume in the titration process. The burette is filled with sodium hydroxide to measure its quantity.
The pipette is used to transfer the volume of the solution that is known (hydrochloric acid) and the measuring cylinder is used to measure the liquid (water) that is used in chemistry experiments.
Therefore, option C. pipette, burette, and measuring cylinder are the apparatus used in the titration process.
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3. Which of the following is a property of a metal?
A. brittle
B. bendable
C. poor conductor of heat and electricity
D. usually dull in appearance
Answer:
the answer would be d. usually dull in appearance
Explanation:
because brittle bendable and poor conductor of heat and electricity are all for the non-metals
Answer:
C !!
Explanation:
hope this helps! usually people classify metals based on if they can conduct heat or electricity
The weak base ionization
constant (Kb) for Clois
equal to:
A
B
[CIO-][H30+)
[HOCI]
[HCIO][OH-]
[CIO-]
Answer:
The answer would be [HCIO][OH-]
_________
[CIO-]
Explanation:
So, the answer would be (b).
¿A qué se llama Recursos químicos en Química Industrial? ¿Cómo logran convertirse en bienes de consumo para la sociedad?
La respuesta correcta para esta pregunta abierta es la siguiente.
Desafortunadamente, no anexas opciones o incisos para contestar la pregunta.
Sin embargo, podemos comentar lo siguiente.
¿A qué se llama Recursos químicos en Química Industrial? ¿Cómo logran convertirse en bienes de consumo para la sociedad?
Hablando de Química Industrial, los recursos químicos son todos aquellos recursos que se utilizan para la extracción, procesamiento, y fabricación de los recursos naturales y materias primas para la elaboración de productos que posteriormente serán utilizados por otras industrias para ofrecerlas y venderlas como productos para el consumo masivo de las personas.
Este procesamiento de substancias para transformarlas en productos de consumo en general va encaminado a beneficiar a diferentes sectores como la medicina, los endulzantes, los fertilizantes, los saborizantes, los insecticidas, los plaguicidas, colorantes, y todo tipo de sustancia que pueda ser industrializada para su consumo final.
El fluoruro de hidrógeno HF que se utiliza en
la obtención de los freones (los cuales
destruyen la capa de ozono de la
estratosfera), se prepara mediante la
siguiente reacción: CaF2 + H2SO4
CaSO4 + 2HF Si se hacen reaccionar 50gr
de CaF2 con 100 gr de H2SO4 (masas
atómicas Ca=40,F=19, H=1, S=32, O=16)
Answer:
25.6g de HF son producidos
Explanation:
...¿Cuánto HF es producido?
Para resolver este problema debemos convertir la masa de cada reactivo a moles usando su masa molar. Como la reacción es 1:1, el reactivo con menor número de moles es el reactivo limitante. Con las moles del reactivo limitante podemos obtener las moles de HF y su masa así:
Moles CaF2:
Masa molar:
1Ca = 40g/mol
2F = 19*2 = 38g/mol
40+38 = 78g/mol
50g CaF2 * (1mol/78g) = 0.641 moles CaF2
Moles H2SO4:
Masa molar:
2H = 2g/mol
1S = 32g/mol
4O = 64g/mol
98g/mol
100g H2SO4 * (1mol / 98g) = 1.02 moles H2SO4
Como las moles de CaF2 < Moles H2SO4: CaF2 es reactivo limitante.
Moles HF usando la reacción:
0.641 moles CaF2 * (2mol HF / 1mol CaF2) = 1.282 moles HF
Masa HF:
Masa molar:
1g/mol + 19g/mol = 20g/mol
1.282 moles HF * (20g/mol) =
25.6g de HF son producidos3. If there were multiple products comment on finding the mixture melting point of the products. Does your sample appear to be a mixture or pure
Answer:
If there were multiple products, we can take each product and mixed with a sample of a pure compound that we suspect might be the same as the product. Then, we taking the melting point of this mixture that contains one of our product and pure sample. Then, we can observe the change in melting point, if there is no change in melting point or the melting stays in the same range of the pure compound. Then, the that product along with the pure sample are actually the same compound, not a mixture of two compounds. However, if the melting point for our pure sample compound changed or didn't stay in the same range after the mixing with on of our products. then we can conclude that this product and the pure sample are completely different compound, and indeed they are a mixture.
Pleaseeeeeeee Help ASAP!!
Formula of xenon trioxide = XeO3
Relative atomic mass: Xe = 131.29, O = 16
Question 1
number of moles = mass / molar mass
n of XeO3 = 9.07 / 131.29 + 3(16)
= 0.05059 mol
number of moles = number of particle / Alvagadro's constant
0.05059 = number of molecule / 6.02 x 10²³
number of molecules = 3.046 x 10²²
Question 2
number of moles = number of particle / Alvagadro's constant
number of moles = 3.22 x 10²² / 6.02 x 10²³
number of moles = 0.05349 mol
number of moles = mass / molar mass
0.05349 = mass / 131.29 + 3(16)
mass = 9.590g
heyy guys, so basically i need help with stoichiometric calculation I will give you 100 points just to answer all of these answers accurately with working out (ps ill mark you brainliest x), thanks. PLEASE HELPPP. I'm desperate x
3. What masses of ethanol and ethanoic acid would need to be reacted together to give 1 g of ethyl ethanoate?
C^2H^5OH + CH^3CO^2 H → CH^3CO^2C^2H^5 + H^2O
4. What mass of iron(III) oxide would need to be reduced to produce 100 tonnes of iron in a blast furnace?
Fe^2^O^3 + CO → Fe + CO^2
5. What mass of silver nitrate as a solution in water would need to be added to 5 g of sodium chloride to
ensure complete precipitation of the chloride?
AgNO^3(aq) + NaCl (aq) → AgCl (s) + NaNO^3(aq)
6. Copper(II) oxide reacts with sulphuric acid to produce copper(II) sulphate. If this is allowed to crystallise the formula of the crystals is CuSO 4 .5H 2 O. What mass of copper oxide would be needed to produce 100 g of crystals?
CuO + H^2O + H^2SO^4 = CuSO^4 .5H^2O
7. In the following reactions calculate the mass of precipitate formed from 20 g of the metal salt in each case.
a. ZnSO^4 (aq) + 2NaOH → Zn(OH)^2(s) + Na^2SO^4(aq)
b. Al^2 (SO^4 ) 3(aq) + 6NaOH → 2Al(OH)^3(s) + 3Na^2SO^4(aq)
c. MgSO^4(aq) + 2NaOH → Mg(OH)^2(s) + Na^2^SO^4(aq)
Answer:
3. The mass of ethanol required is approximately 0.522869 g
The mass of ethanoic acid required is approximately 0.68156 g
4. The mass of iron (III) oxide required is approximately 285.952.189.095 tonnes
5. The mass of silver nitrate required is approximately 14.53 grams
6. The mass of copper oxide that would be needed is approximately 31.86 grams
7. a. The mass of the precipitate, Zn(OH)₂ formed is approximately 49.712 grams
b. The mass of the precipitate, Al(OH)₃ formed is approximately 13 grams
c. The mass of the precipitate, Mg(OH)₂, formed is approximately 14.579925 grams
Explanation:
3. The 1 mole of ethanol and 1 mole of ethanoic acid combines to form 1 mole of ethyl ethanoate
The number of moles of ethyl ethanoate in 1 gram of ethyl ethanoate, n = 1 g/(88.11 g/mol) = 1/88.11 moles
∴ The number of moles of ethanol = 1/88.11 moles
The number of moles of ethanoic acid = 1/88.11 moles
The mass of ethanol = (46.07 g/mol) × 1/88.11 moles = 0.522869 g
The mass of ethanoic acid in the reaction = 60.052 g/mol × 1/88.11 moles ≈ 0.68156 g
4. 1 mole of iron(III) oxide reacts with 1 mole of CO₂ to produce 1 mole of iron
The number of moles in 100 tonnes of iron= 100000000/55.845 = 1790670.60614 moles
The mass of iron (III) oxide required = 159.69 × 1790670.60614 = 285952189.095 g ≈ 285.952.189.095 tonnes
5. The number of moles of NaCl in 5 grams of NaCl = 5 g/58.44 g/mol = 0.0855578371 moles
The mass of silver nitrate required, m = 169.87 g/mol × 0.0855578371 moles ≈ 14.53 grams
6. The number of moles of CuSO₄·5H₂O in 100 g of CuSO₄·5H₂O = 100 g/(249.69 g/mol) ≈ 0.4005 moles
The mass of copper oxide required, m = 79.545 g/mol × 0.4005 moles ≈ 31.86 grams
7. a. The number of moles of NaOH in the reaction = 20 g/(39.997 g/mol) ≈ 0.5 moles
2 moles of NaOH produces 1 mole of Zn(OH)₂
0.5 moles of NaOH will produce 0.5 mole of Zn(OH)₂
The mass of 0.5 mole of Zn(OH)₂ = 0.5 mole × 99.424 g/mol = 49.712 grams
The mass of the precipitate, Zn(OH)₂ formed = 49.712 grams
b. 6 moles of NaOH produces 2 moles Al(OH)₃
20 g, or 0.5 mole of NaOH will produce (1/6) mole of Al(OH)₃
The mass of the precipitate, Al(OH)₃ formed, m = 78 g/mol×(1/6) moles = 13 grams
c. 2 moles of NaOH produces 1 mole of Mg(OH)₂, therefore;
20 g or 0.5 moles of NaOH formed (1/4) mole of Mg(OH)₂
The mass of the precipitate, Mg(OH)₂, formed, m = 58.3197 g/mol × (1/4) moles = 14.579925 grams
Answer:
Explanation:
i will show in details how 2 do the 1st Q n u can do the rest by following the way how it is done
3. given C^2H^5OH + CH^3CO^2H → CH^3CO^2C^2H^5 + H^2O
molar ratio of ethanol, ethanoic acid and ethyl ethanoate is 1 : 1 : 1
so mass = no. of moles * molecular mass
for same no. of moles, mass / molecular mass is the same
molecular mass of CH^3CO^2C^2H^5 = 12+1*3+12+16*2+12*2+5*1 = 88
molecular mass of C^2H^5OH = 12*2+1*5+16+1 = 46
molecular mass of CH^3CO^2H = 12+1*3+12+16*2+1 = 60
1 g of ethyl ethanoate = 1/88 mole
it requires 1/88*46 = 0.5227 g of ethanol; and
1/88*60 = 0.6818 g of ethanoic acid
to react together to form 1 g of ethyl ethanoate
Why does it stop expanding when you stop blowing air into it
Answer:
this is because of collisions of molecules present in that particular system.
Explanation:
For instance, when air is filled in a balloon then the number of the molecules of air inside the balloon increases. As a result more collisions of molecules take place with the walls. This gives rise to high air pressure on the walls which causes the balloon to expand and get inflated.
Which option best describes the water cycle?
Si un carabinero está controlando velocidad en la carretera y pistolea mi vehículo, está midiendo mi rapidez media
Answer:
Si.
Explicación:
Si un oficial de policía está controlando la velocidad en la carretera y dispara al vehículo con una pistola de radar. El policía mide la velocidad media del coche con esta pistola de radar. Una pistola de radar es un dispositivo que se utiliza para medir la velocidad de los objetos en movimiento que fue inventado por Bryce K. Brown en el año de 1954. La pistola de radar se utiliza con fines policiales para calcular la velocidad de los vehículos en movimiento.
True or false: Denaturation of an enzyme increases the rate at which it may catalyze a chemical reaction.
Question 2: Heat (5 points)
A. Describe the following heat equations, and identify the indicated variables.
i. Q = mcΔT; identify c. (1 point)
ii. Q = mLvapor; identify Lvapor. (1 point)
iii. Q = mLfusion; identify Lfusion. (1 point)
Answer:
(i) specific heat
(ii) latent heat of vaporization
(iii) latent heat of fusion
Explanation:
i. Q = mcΔT; identify c.
Here, Q is heat, m is the mass, c is the specific heat and ΔT is the change in temperature.
The amount of heat required to raise the temperature of substance of mass 1 kg by 1 degree C is known as the specific heat.
ii. Q = mLvapor; identify Lvapor
Here, Q is the heat, m is the mass and L is the latent heat of vaporization.
The amount of heat required to convert the 1 kg liquid into 1 kg vapor at constant temperature.
iii. Q = mLfusion; identify Lfusion
Here, Q is the heat, m is the mass and L is the latent heat of fusion.
Here, Q is the heat, m is the mass and L is the latent heat of vaporization.
The amount of heat required to convert the 1 kg solid into 1 kg liquid at constant temperature.
(i) c is the molar heat capacity of the substance.
(ii) Lvapor is the latent heat of evaporation of the substance
(iii) Lfusion is the latent heat of fusion of the substance
All the 3 equations fall under Calorimetry.
In all the equation Q is the amount of heat required.
(i) First equation represents the amount of heat required to raise the temperature of a substance of mass m.
Q = mcΔT
here c is the molar heat capacity of the substance and ΔT is the chnage in temperature.
(ii) Second equation represents the amount of heat required to convert a substance of mass m from liquid phase to vapour phase.
Q = mLvapor
here Lvapor is the latent heat of evaporation of the substance
during evaporation no change in temperature occurs.
(iii) Third equation represents the amount of heat required to convert a substance of mass m from solid phase to liquid phase.
Q = mLfusion
here Lfusion is the latent heat of fusion or melting of the substance
during fusion no change in temperature occurs.
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Help ASAP only right answers only no spam don’t answer if you don’t know
Answer:
theory
Explanation:
if you assume something that you didn't see occuring it is called a theory