Answer:
v = 78.5 km/h
Explanation:
It is given that, the distance between one city to another is 314 km. The overall trip takes 4 hours. We need ton find average velocity. It is equal to the total displacement divided by total time taken. So,
[tex]v=\dfrac{d}{t}\\\\v=\dfrac{314\ km}{4\ h}\\\\v=78.5\ km/h[/tex]
So, average velocity is 78.5 km/h.
How many moles of CO2 is needed to fill an 80.0 L tank to a pressure of 150.0 atm at 27.0°C?
Answer:
487 moles of CO2 is needed
Explanation:
What we need to use here is the ideal gas equation.
Mathematically;
PV = nRT
Since we are calculating the number of moles, we can rewrite the equation to be;
n = PV/RT
from the question, we identify the following;
P is the pressure at 150 atm
V is the volume at 80L
T is the temperature which is 27+273 = 300K
R is the molar gas constant which is 0.0821 L atm K^-1 mol^-1
Substituting these values, we have;
n = (150 * 80)/(0.0821 * 300) = 487.2 which is approximately 487 moles
what is microbial oxidation?
Answer:
Bacteria biooxidation is an oxidation process caused by microbes where the valuable metal remains (but becomes enriched) in the solid phase. In this process, the metal remains in the solid phase and the liquid can be discarded.Hope it helps you!
Answer Microbial oxidation of sulfur is the oxidation of sulfur by microorganisms to produce energy. The oxidation of inorganic compounds is the strategy primarily used by chemolithotrophic microorganisms to obtain energy in order to build their structural components, survive, grow and reproduce.
Explanation:
Un recipiente de 3L lo llenamos de O 2 a 10°Cy 740 mm de presión cuantos gramos se introduce? cuantos moles? cual densidad? ¿Cuál debería ser la temperatura para que la presión se redujera a la mitad?
Answer:
Ve explicación abajo
Explanation:
Responderemos esta pregunta en dos partes.
PAra la primera parte, usaremos la expresión de gases ideales la cual es:
PV = nRT (1)
Donde:
P: Presión (atm)
V: Volumen (L)
n: moles
R: constante universal de gases (0.082 L atm/ mol K)
T: Temperatura (K)
En este caso, tenemos un recipiente que se llena completamente de oxígeno (O₂) hasta 3 L. Este sería su volumen. a la presión de 740 mmHg, esta es la presión y debemos convertirla a atmosfera, y la temperatura de 10 °C que debe ser convertida a Kelvin. Con esos datos se puede calcular primero los moles de oxigeno y luego los gramos.
Transformando las unidades de presión y temperatura tenemos:
P = 740 mmHg * 1 atm / 760 mmHg = 0.974 atm
T = 10 + 273 = 283 K
Con estos datos, usaremos la expresión (1) para calcular los moles:
n = PV / RT
n = 0.974 * 3 / 0.082 * 283
n = 0.1259 moles
Con estos moles, se pueden calcular los gramos usando el peso molecular del oxigeno que es 16 g/mol. (Como tenemos 2 atomos, serían 32 g/mol):
m = n * PM
m = 0.1259 * 32
m = 4.0288 g
Ahora que tenemos la masa se puede calcular la densidad con la siguiente expresión:
d = m/V
Usando el volumen en mililitros (3 * 1000 = 3000 mL) y la masa obtenida, calculamos entonces la densidad.
d = 4.0288 / 3000
d = 0.00134 g/mL
Para la segunda y ultima parte del ejercicio, usaremos la ley de boyle donde se mantiene el volumen constante (en este caso 3 L) y solo se altera presión y temperatura. De esta forma calcularemos la temperatura necesaria para que la presión se reduzca a la mitad:
P₁/T₁ = P₂/T₂
Y queremos saber es la temperatura para que la presión sea la mitad de la presión inicial, por tanto:
P₂ = 1/2P₁
Sabiendo que la temperatura es de 10 °C (283 K) tenemos entonces:
P₁/T₁ = P₁/2T₂ Se cancelan las presiones y nos queda
1/T₁ = 1/2T₂
2T₂ = T₁
T₂ = 1/2T₁
Reemplazando la temperatura:
T₂ = 283 / 2
T₂ = 141.5 K
The number of electrons can accommodate in K shell is 8. True or False
Answer:
true
no explanation
8. What are two physical changes that cooling a hot substance may result in?
Answer:
Explanation:
Two possible changes are
a phase change. If water is presented in the form of steam, it may change into liquid, or eventually into a solid. While in a phase change, the temperature might change.a temperature change. Water at 65o what cooled can go down to 5o. There is no phase change, but there is a temperature change.Which element below contains 10 protons?
the le answer to dis problem is neon. it has 10 protons
A chemist dissolves 398. Mg of pure hydrochloric acid in enough water to make up 210. ML of solution. Calculate the pH of the solution. Round your answer to 3 significant decimal places.
Answer:
THE pH OF THE SOLUTION IS 1.28
Explanation:
Step 1: Calculate the mass concentration of HCl
398 mg in 210 mL
1 L = 10^3 mL
1 g = 10^3 mg
398 *10^-3 g in 210 *10^-3 L
398 *10^-3 in 0.210 L
mass concentration = (0.398 * 1/ 0.210) g/dm3
= 1.895 g/dm3
Step 2: calculate the molar concentration
Molar mass of HCl = ( 1 + 35.5) = 36.5 g/mol
Molar concentration = mass concentration / RMM
Molar conc. = 1.895 / 36.5
Molar conc. = 0.0519 mol/dm3
So therefore, the molar concentartion of the solution is equal to the concentration of HCl.
In other words, [HCl] = 0.0519 mol/dm3
This shows that at 1 L of this solution contains 0.0519 moles of HCl
Step 3: write the dissiociation equation of HCl in water
HCl(aq) + H2O(l) --------> H30^+ (aq) + Cl- (aq)
Since HCl is a strong acid, it will dissociate completely in water forming the above products.
So we can say that:
[H3O+] = [HCl] = 0.0519 moles/ dm3
Step 4: calculate the pH
pH = -log[H3O+]
pH = -log (0.0519)
pH = 1.28(3 significant decimal place)
The pH of the solution is 1.28
If the neutral solution was boiled to dryness, what would be the formula of the resulting salt.
Answer:
Forumula
XOH + HY = XY + H2O
Explanation:
Salt formed from: Salt Solution
Strong acid + Strong base Neutral
Strong acid + Weak base Acidic
Weak acid + Strong base Basic
Neutral solution example
NaCl = Sodium chloride
HCl = H+ and Cl-
NaOH = Na+ and OH-
OH- = Strong Base
H+ = Strong Acid
Sodium chloride, formed from neutralization of HCl by NaOH.
NaOH + HCl = NaCl + H2O
NaCl in water is not acidic or basic, since it's ions cannot hydrolyze.
So formula would be XOH + YH = XY + H2O
Which statement correctly describes metallic bonds?
A.
They form when certain atoms lose electrons and other atoms gain electrons.
B.
They involve an attraction between anions and cations.
C.
They always involve both a metal and a nonmetal.
D.
They can only form between atoms of the same element.
E.
They form because electrons can move freely between atoms.
Answer: D
Explanation:
the atom of the metal loses one electron which becomes delocalised and is attragted by the positive nucleus leading to formation of metallic bond.
E. They form because electrons can move freely between atoms
Top guy is incorrect↑
#Platofam
Calculate the molarity of a solution that has 2.02 mol KNO3 in a 250.0
mL solution.
Explanation:
Molarity = M = mol/1 liter
in sol 250 mL there are KNO3 2.02 mol
in sol 1000 mL there are KNO3 = 2.02/250 × 1000
= 8.08 mol/liter
Which of the following are considered pure substances? element compound homogeneous mixture heterogeneous mixture
Answer:
element and compound.
Explanation:
reason
an element is a pure substance that cannot be broken down into simpler substances by any ordinary physical or chemical process.
and compound is a pure substance that consists of two or more elements held together in fixed proportions by natural forces called chemical bonds.
homogeneos and heterogenous mixtures are considered impure substances because they dont have a definite composition.
In chemistry, pure substances have been defined by matter that has characteristic properties. An element and compound are pure substances. Thus, options 1, and 2 are correct.
What are pure substances?Pure substances have been the matter that is characterized by the presence of a fixed chemical composition that cannot be physically separated by the processes like filtration, evaporation, etc.
Elements and compounds are pure substances as elements are not broken physically or chemically to form simple -small substances like zinc. Furthermore, compounds are formed by the combination of pure substances like water.
Homogeneous mixtures and heterogeneous mixtures are not pure substances as they lack fixed ratios and proportions that cannot be said to have definite composition.
Therefore, options 1 and 2. are elements and compounds are pure substances.
Learn more about pure substances, here:
https://brainly.com/question/18634105
#SPJ2
Which of the following elements will sulfur most readily react with in order to help it fill its outer shell with 8 electrons?
arsenic (As)
astatine (At)
argon (Ar)
magnesium (Mg)
Answer:
Magnesium
Explanation:
Using the KLMN styled electronic configuration, the electronic configuration of sulphur with atomic number 16 is 2, 8,6
What this means is that it needs extra 2 electrons to fill into its M shell to attain the octet configuration.
Now let’s look at Magnesium, with atomic number 12, the electronic configuration it has is 2,8,2.
This means it has 2 extra electrons to give away so as to attain its own stability.
The sulphur atom will gladly accept the two electrons which the magnesium atom wants to give away. This makes it the perfect element to be reacted with sulphur to make it attain its octet configuration
ASSERTION AND REASON DIRECTION : In the following questions, a statement of assertion (A) is followed by a statement of reason (R). Mark the correct choice as: (a) Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A). (b) Both assertion (A) and reason (R) are true but reason (R) is not the correct explanation of assertion (A). (c) Assertion (A) is true but reason (R) is false. (d) Assertion (A) is false but reason (R) is true. Questions: 1. Assertion : Camphor disappears without leaving any residue. Reason : Camphor undergoes sublimation. (1 Point) Option a Option b Option c Option d 2. Assertion : Liquids diffuse easily as compared to gases. Reason : Inter molecular forces are greater in liquids. (1 Point) Option a Option b Option c Option d 3.Assertion : There is no change in the temperature of a substance when it undergoes a change of state through it is still being heated. Reason : The heat supplied is absorbed either as latent heat of fusion or as latent heat of vaporization. (1 Point) Option a Option b Option c Option d 4.Assertion : During evaporation of liquids, the temperature remains unaffected. Reason : Kinetic energy of the molecules is directly proportional to temperature. (1 Point) Option a Option b Option c Option d 5.Assertion : It is easier to cook food at high altitudes. Reason : The boiling point of water decreases at high altitudes. (1 Point) Option a Option b Option c Option d 6.Assertion : A gas can be easily compressed by applying pressure. Reason : Since the inter-particle spaces in the gaseous state are very small, they cannot be decreased by applying pressure. (1 Point) Option a Option b Option c Option d 7.Assertion : The inter molecular forces in solid state are stronger than those in the liquid state. Reason : The space between the particles of matter is called inter molecular space. (1 Point) Option a Option b Option c Option d 8.Assertion : When a beam of light is passed through a colloidal solution placed in a dark place the path of the beam becomes visible. Reason : Light gets scattered by the colloidal particles. (1 Point) Option a Option b Option c Option d 9.Assertion : A solution of table salt in a glass of water is homogeneous. Reason : A solution having different composition throughout is homogeneous. (1 Point) Option a Option b Option c Option d 10.Assertion : A true solution do not exhibits Tyndall effect. Reason : A true solution is a heterogeneous mixture.Immersive Reader (1 Point) Option a Option b Option c Option d
Answer:
1) A
2) D
3) A
4) B
5) D
6) C
7) B
8) A
9) C
10) C
Explanation:
Sublimation refers to the direct change of a substance from solid to gas without passing through a liquid stage. Hence if camphor changes directly from solid to gas, camphor is a sublime substance.
Gases have a higher rate of diffusion than liquids because liquids have greater intermolecular forces while the intermolecular forces in a gas is negligible.
When a substance is heated, a point comes in which heat is supplied but the temperature of the body does not change. This is the point of phase change and the heat supplied at this point may be referred to as latent heat of fusion or vaporization depending on the particular process going on.
While it is true that evaporation occurs at all temperatures and the kinetic energy of molecules is directly proportional to the temperature of a body but the later statement does not explain the former. Rather evaporation occurs because some particles at the surface of the liquid are more energetic and escape due to unbalanced attractive forces acting on them.
Due to decrease in temperature, it takes a longer time to cook food at high altitudes but a lesser time to boil water at higher altitudes.
Gases are easily compressible by applying pressure because gases occupy negligible volume compared to the volume of the container. There is a significant inter particle space between gas particles.
The solid state contains the strongest degree of intermolecular forces. However, the reason offered, though correct, is not the correct explanation of the assertion stated.
This is the Tyndall effect. Colloidal particles scatter light rays and the path of the light becomes visible in the colloidal solution.
Salt solution is homogeneous. A homogeneous solution contains only one phase throughout. If it has a different composition, the solution is heterogeneous. Hence the explanation is false.
A true solution will not exhibit Tyndall effect because the particles are less than colloidal size. A true solution cannot be a heterogenous mixture hence the reason is false.
Now molecules: ____ molecules of H2 + ____ molecules of O2 → ____molecules of H2O
Answer:
4 H2 + 1 O2 = 2 H2O
Non-native species are typically introduced into an area because they serve a purpose. Why was kudzu introduced into the United States? Check all that apply.
Answer:
Explanation:
The Kudzu is a plant that was introduced to the United States from Japan in the year 1876. In the United States it was introduced as an ornamental plant but with a reason which was to prevent soil erosion. Kudzu was disseminated as being high-protein content used to steer feed as well as a spreading plant to counteract soil erosion.
Answer:
Kudzu was introduced as an ornamental plant.
+
Kudzu was introduced as a way of preventing soil erosion.
So, A and D!
Which structural formula represents a member of the alkene series?
Answer:
C4H8. butene
Click on the diagram to choose which atom is more reactive.
Answer:
Second graph is more reactive.
Explanation:
I just did the lesson myself, chose the first graph, and obviously got it wrong.
Therefore I can tell you with 100% certainty that the correct answer is graph #2 in this case. Hope this helps.
A chemist dilutes 185 of the 3.0 M solution with water until a new volume of 750 is obtained. Calculate the new concentration
Answer:
0.74M
Explanation:
Step 1 :
Data obtained from the question.
Initial concentration (C1) = 3M
Initial volume (V2) = 185mL
Final volume (V2) = 750mL
Final concentration (C2) =..?
Step 2:
Determination of the new concentration of the solution.
The new concentration of the solution can be obtained by using the dilution formula as shown below:
C1V1 = C2V2
3 x 185 = C2 x 750
Divide both side by 750
C2 = 3 x 185 / 750
C2 = 0.74M
Therefore, the new concentration of the solution is 0.74M
name the scientist who studied the movement of pollen grains suspended in water through a microscope what is the phenomenon known as
Answer:
the scientist who studied the movement of pollen grains grains suspended in water through a microscope is Robert Hooke
What happens when a piece of Mg ribbon is burnt? Name the
new substance formed. Write a balanced chemical equation.
Answer:
When a Magnesium Ribbon is burnt, a powdery substance called magnesium oxide is formed.
Explanation:
There has obviously been a chemical change because several chemical properties of the magnesium have been modified: the color, the texture and the mass.
The increase in mass is due to the fact that oxygen from the air has combined with the magnesium to make magnesium oxide, MgO.
The chemical equation, Mg + O2 MgO shows this reaction but it needs to be balanced to make 2Mg + O2 2MgO.
Using stoichiometry, we can convert this eqation into an equation with moles:
2 mol Mg + 1 mol O2 2 mol MgO.
Next, we convert to grams using atomic masses obtained from the periodic table:
48g Mg + 32g O2 80g MgO
Lastly, we determine the same thing in the proportions we used. In other words, we used only 0.15g of Mg (not 48g) so everything needs to be divided by 320. So 80 / 320 = 0.25 g. If we burn 0.15 g of Mg, we obtain 0.25 g of MgO.
Hope this helps!!!
This is my first answer.
[ ]transport moves substances from an area of high concentration to an area of low concentration.
Answer:
The answer is Diffusion.
Explanation:
Diffusion is a movement of molecules(substances) from a region of high concentration to a region of low concentration down a concentration gradient.
Answer:
Active
Explanation:
During active transport, substances move against the concentration gradient, from an area of low concentration to an area of high concentration. This process is “active” because it requires the use of energy.
Given 700 ml of oxygen at 7 ºC and 106.6 kPa pressure, what volume does it take at 27ºC and 66.6 kPa pressure
Answer:
1.20 L = 1200 mL
Explanation:
P1V1/T1 = P2V2/T2
V2 = P1*V1*T2/(T1*P2)
V1 = 700ml =0.700 L
P1 = 106.6 kPa
T1 = 7+273.15 = 280.15 K
T2 = 27 + 273.15 = 300.15 K
P2 = 66.6 kPa
V2 = 106.6*0.700*300.15/(280.15*66.6)= 1.20 L=1200 mL
N2 + 3H2 —> 2NH3
If 35.0g of nitrogen gas are mixed with 12.0g of hydrogen gas, what mass of ammonia is produced?
Explanation:
47.0g is the mass of ammonia
what is the pOH of 2.5 M NaOH
Answer:
-0.398
Explanation:
pOH is a measure of hydroxide ion (OH-) concentration in a solution. A basic solution If a solution has pOH less than 7 then it is a basic solution and if pOH is greater than 7 then it is an acidic solution. Neutral solutions have pOH equal to 7.
[tex]pOH=-\log \left [ OH^- \right ][/tex]
To find pOH of 2.5 M NaOH, solve [tex]pOH=-\log \left [ 2.5 \right ][/tex] = -0.398
Which element when combined with chlorine would most likely form an ionic compound
Answer:
Na (Sodium)
Explanation:
Sodium is a metal, and when combined with Chlorine (which is a non-metal) it creates an ionic compound
Option C is correct. The Sodium combined with Chlorine to form an ionic compound.
Ionic Compound:
These are the compounds that are made up of two ions, one positive and one negative. In the solution, they conduct electricity. They formed when a metal interacts with a non-metal.
For example- NaCl
NaCl in the water solution form positive Sodium and Negative Chlorine ion. The solution of NaCl conduct electricity,Na is a metal while Cl is a non- metal. Oxygen, Carbon and phosphorus are non-metal, they will not form an ionic compound.Therefore, the Sodium combined with Chlorine to form a an ionic compound.
To know more about ionic compounds, refer to the link:
https://brainly.com/question/10748806
Given the unbalanced equation below, how many moles
of Li would be needed to produce 6 moles of LiCl?
Li + Cl2 → Lici
Answer: 6 mol Li
Explanation:
The first step is to balance the equation.
2Li+Cl₂⇒2LiCl
We would need our conversions to find the amount of moles of Li needed to produces 6 mol LiCl.
[tex]6molLiCl*\frac{2molLi}{2molLiCl} =6molLi[/tex]
What volume of 18.0 M H2SO4 is needed to contain 2.45 moles of H2SO4?
Answer:
0.136 L = 136 mL
Explanation:
18.0M = 18.0 mol/L
2.45 mol /(18.0 mol/L) = 0.136 L = 136 mL
Why does the source of chemical energy from wood can be renewed? A. Cells in the wood constantly produce chemical energy. B.Wood can constantly obtain chemical energy from the Sun. C.Wood has unlimited supply of chemical energy. D.Wood is from living organisms.
The source of chemical energy from wood can be renewed as wood can constantly obtain chemical energy from the sun as it is a renewable source of energy.
What is chemical energy?
Energy which is stored in the chemical bonds of chemical compounds is called chemical energy.Chemical energy is released during the occurrence of chemical reaction.Reactions wherein energy is given out in the form of heat is called exothermic reactions.
Chemical energy can be converted to other forms of energy like electrical energy during the process of electrolysis and to thermal energy as in the case of thermal engines.
It can also be converted to kinetic energy during explosions . It is stored in batteries, coal, biomass, food, vehicle air bags,etc.Chemical energy of plants is utilizes during the process of photosynthesis.
Learn more about chemical energy,here:
https://brainly.com/question/7805320
#SPJ5
if a plant needs to make 12.6 g of glucose(c6h1206), how many grams of water are required?
Answer: 7.6 g of water are required to make 12.6 g of glucose
Explanation:
Moles is calculated by using the formula:
[tex]Moles=\frac{\text{Given mass}}{\text{Molar mass}}[/tex]
[tex]{\text {moles of glucose}}=\frac{12.6g}{180g/mol}=0.07moles[/tex]
The balanced chemical equation is:
[tex]6CO_2+6H_2O\rightarrow C_6H_{12}O_6+6O_2[/tex]
According to stoichiometry:
1 mole of glucose is produced by = 6 moles of water
Thus 0.07 moles of glucose is produced by =[tex]\frac{6}{1}\times 0.07=0.42[/tex] moles of water
Mass of water required =[tex]moles\times {\text {Molar mass}}=0.42mol\times 18g/mol=7.6g[/tex]
Thus 7.6 g of water are required to make 12.6 g of glucose
This right guys? plz help