Answer:
Explanation:
First of all, 1 mol of Sodium Sulphide has molecular mass of
S = 32
Na2 = 2*23 = 46
The formula of NaS is actually Na2S. It's molecular mass = 78
How many grams of Na2S are present
Grams present = 240 - 162 = 78 which is exactly 1 mol.
The remainder is water.
The molecular mass of water = 2 + 16 = 18
162 grams of water = 162/18 = 9 mols of water.
So the correct formula is Na2S*9H20
what is the most appropriate unit to measure the following; the length of a football field. b) the diameter of a tennis ball
Explanation:
a) m (metre)
b) mm (millimeter)
how can you separate mixture of suphur, nacl and nh4cl
Answer:
Ammonium chloride, iron ,Sulphur and salt mixed together... they can be separated in the following methods.
1. Ammonium chloride is separated by sublimination... NC4CI is sublimable. Heat the mixture in a china dish and collect the funds of NC4CI (sublimable substance)
2. Bring a magnet close to the remaining mixture. Iron is magnetic substance and thus, it will be attracted towards the magnet. Iron is separated.
3. Sulphur is insoluble in water and salt is soluble. Add water to the remaining mixture and then wait for sedimentation. Separate the sulphur by decantation.
4. Heat the filtered salt solution to obtain salt.
During a reaction, the enthalpy of the reactants and the products are not equal. What does this result in?
O A. Spin of electrons is reversed
O B. Change in chemical composition
O C. None of these
D. Absorption or release of energy
Answer:c
Explanation:
Answer: C
i think none of these
Explanation:
Which star has the highest surface temperature
A. blue star
B. yellow star
C. white star
D. red star
Answer:
The blue star is the hottest star.
Explanation:
Red stars are cooler than the sun, with surface temperatures of 3,500 K for a bright red star and 2,500 K for a dark red star. The hottest stars are blue, with their surface temperatures falling anywhere between 10,000 K and 50,000 K
Calculate the amount of mole of iron produced from the reaction of 15.9 grams of iron oxide.
Fe2O3 + 3 H2 +2 Fe + 3 H2O
Answer:
0.19875
Explanation:
nFe2O3=0.099375
nFe=2nFe2O3=0.19875
10. Fuel oil, gasoline, kerosene and naphtha are four fractions obtained from the fractional
distillation of petroleum.
What is the order of the boiling points of these fractions?
Answer:
option b
Explanation:
answer from gauth math
A cactus needle is a structure made of different tissues that work together to protect the plant from animals that might want to eat it. What level of body organization does a cactus needle represent?
A. Cell
B. Organ
C. Cell system
D. Body system SUBMIT
Jane wants to study how a person's heart and lungs respond to intense
exercise. She measures the heart rate and breathing rate of 10 people before,
during, and after a 5K race. Which body systems is she studying?
A. Cardiovascular and respiratory
B. Skeletal and urinary
C. Digestive and nervous
D. Muscular and reproductive
SUBMIT
The boiling points of diatomic halogens are compared in the table.
Boiling Points of Diatomic
Halogens
Molecule
Boiling Point
F2
-188 °C
Cl2
-34 °C
Br2
59 °C
12
184°C
Which of the following statements best explains the trends in boiling points?
The atomic size increases down the group, and this decreases the strength of the intermolecular forces.
The total number of electrons decreases down the group, and this decreases the strength of the intermolecular forces.
The total number of electrons increases down the group, and this increases the strength of the intermolecular forces.
The chances of forming a permanent dipole increases down the group, and this increases the strength of the intermolecular forces.
Which of the following statements best explains the trends in boiling points?
A. The atomic size increases down the group, and this decreases the strength of the intermolecular forces.
A is incorrect
B. The total number of electrons decreases down the group, and this decreases the strength of the intermolecular forces.
B is incorrect
C. The total number of electrons increases down the group, and this increases the strength of the intermolecular forces.
C is correct
D. The chances of forming a permanent dipole increases down the group, and this increases the strength of the intermolecular forces.
D is incorrect
The boiling point increase down a group because the total number of electrons increases down the group, and this increases the strength of the intermolecular forces. Hence option C is correct.
What is boiling point?Boiling point of a substance is the temperature at which the substance changes from its liquid state to vapour state. Boiling point of a molecule or compounds depends on the bond type, molecular weight, temperature and pressure.
For ionic compounds, boiling point will be higher since ionic bonds are stronger than covalent compounds. There is a periodic trend for the physical properties such as boiling point for elements in periodic table.
Down a group, the number of electrons increases and the atomic size also as well as the ionic character increases down a group . These two facts leads to higher intermolecular attraction, thus more temperature have to applied to weaken the bonds.
Higher temperature to be applied means the boiling point of the substance is higher. Therefore, boiling point down a group increases because of the higher intermolecular attraction as said in option C.
To find more about boiling point, refer the link below:
https://brainly.com/question/2153588
#SPJ1
g) silver nitrate + magnesium chloride → silver chloride + magnesium nitrate
Answer:
AgNo3+Mgcl2--->Agcl2+Mg(No3)2
I hope this helps
What is the oxidation state of S in HSO4^2-? (A.P.E.X)
I think there is a typo because I've never seen HSO4 2- before in my life. It should be HSO4-. For that, H is 1+ and each Oxygen is 2-0 totaling 8-. So the oxidation state of sulfur +1 - 8 = 7
So the oxidation state of sulfur is +6
How many molecules are in 35.5 grams of carbon dioxide?
Answer:
you have to use the avogadro's constant of 6.023×10^23 to calculate the number of molecules of carbon dioxide.and you also have to use the molecular mass which is 44.
35.5/44×6.023×10^23
=4.85×10^23
I hope this helps and sorry if it's wrong
What is valence of helium
True or false, the four units that must always be used when using the ideal gas law are liters, atm, Kelvin, and grams
Answer:
False grams is not used
Explanation:
IDEAL GAS LAW
The ideal gas law states that PV = NkT, where P is the absolute pressure of a gas, V is the volume it occupies, N is the number of atoms and molecules in the gas, and T is its absolute temperature.
It is necessary to use Kelvin for the temperature and it is conventional to use the SI unit of liters for the volume. However, pressure is commonly measured in one of three units: kPa , atm , or mmHg . Therefore, R can have three different values.
10. As electrons move through the electron-transport chain,
they lose energy, which is used to form
A. NAD.
B. ADP
C. ATP.
D. GBP
Answer:
NAD
Explanation:
mark me brainlist please
Answer:
They lose energy which is used to form ATP
Which of the following are held together by nonpolar covalent bonds?
The Periodic Table
A. Atoms of phosphorus (P) and chlorine (CI)
B. Atoms of chlorine (CI)
C. Atoms of chlorine (CI) and magnesium (Mg)
D. Atoms of magnesium (Mg)
Answer:
Answer: Atoms of chlorine (CI) and magnesium (Mg)
Answer: Atoms of chlorine (CI) and magnesium (Mg)is your answer
100cm³ of ethane gas diffuses through a porous plug in 100 seconds.What is the molecular mass of the gas Q if 100cm³ of the gas diffuses through the same plug in 121 secknds under the same condition?(C=12.0,H=1.0)
Answer:
The molar mass of gas Q is 43.923 g/mol
Explanation:
The given volume of ethane gas that diffuses through a porous plug in 100 seconds = 100 cm³
Therefore;
The rate of diffusion of ethane gas through the porous plug, [tex]v_{ethane}[/tex], is given as follows;
[tex]v_{ethane}[/tex] = (100 cm³/100 s) = 1 cm³/s
The molar mass of ethane, C₂H₆ = 2×12 g/mol + 6×1 g/mol = 30 g/mol
The given volume of gas, Q, that diffuses through a porous plug in 121 seconds = 100 cm³
∴ The rate of diffusion of the gas, Q, [tex]v_Q[/tex] = 100/121 cm³/s
Graham's Law of diffusion states that the rate of diffusion of a gas is inversely proportional to the square root of the molecular mass of the gas
Mathematically, we have;
[tex]\dfrac{v_A}{v_B} =\sqrt{\dfrac{m_B}{m_A} }[/tex]
Where;
[tex]v_A[/tex] = The rate of diffusion of gas A
[tex]v_B[/tex] = The rate of diffusion of gas B
[tex]m_A[/tex] = The molar mass of the gas A
[tex]m_B[/tex] = The molar mass of the gas B
Therefore, for ethane and gas Q, measured under the same condition, we have;
[tex]\dfrac{v_{ethane}}{v_Q} =\sqrt{\dfrac{m_Q}{m_{ethane}} }[/tex]
[tex]\dfrac{1 \ cm^3/s}{\dfrac{100}{121} \ cm^3/s} =\sqrt{\dfrac{m_Q}{30 \ g/mol} }[/tex]
[tex]m_Q = \left ({\dfrac{121}{100} } \right) ^2 \times 30 \ g/mol = 43.923 \ g/mol[/tex]
The molar mass of gas Q, [tex]m_Q[/tex] = 43.923 g/mol.
Which of the following describes scientists?
О
A. People with only one perspective
B. People with similar personalities
C. People from different backgrounds
D. People with perfect understanding of science
We have two surfaces A and B where same amount of Force is acting. Area of Surface A is greater than Area of Surface B. which of the following will be true *
1 point
Pressure on Surface A > Pressure on Surface B
Pressure on Surface B > Pressure on Surface A
Pressure does not depend on area
Pressure on Surface A= Pressure on Surface B
Answer:
Pressure on Surface A > Pressure on Surface B
Explanation:
Pressu
re on Surface B > Pressure on Surface A
PLZ HELP ME Which of the following lists the levels of body organization in order from most basic to most complex?
A Tissues, organs, body systems, cells
B. Cells, tissues, organs, body systems
C. Cells, organs, body systems, tissues
D. Tissues, cells, organs, body systems
Answer:
It is B
Explanation:
I was able to find my school notes and double-check. I hope you have a nice day!
What are you most likely to observe when an endothermic reaction is taking place?
Answer:
An endothermic reaction is when heat is needed by the reaction, so it draws heat from its surroundings, making them feel cold. Just like a ice pack.
As a person BAC level increase it becomes difficult for them to judge their vehicle distances and speed
Answer:
TRUE
Explanation:
The blood alcohol content is also known as the blood alcohol level or the blood alcohol concentration. It is defined as the measurement of the alcohol intoxication in the body and is used for the legal or the medical purposes.
When the BAC increases in the person's body, the person started to loose clear vision, loss of short term memory, poor muscle coordination, impaired perception and face difficulty in concentrating. Thus it becomes very difficult for a person to drive a car or ride a bike whose BAC has increased.
The driver cannot properly judge the distances between the vehicle and the speed of the vehicle.
Hence the answer is TRUE.
19. If 23.4 grams of hydrogen gas were produced by the reaction below, how many grams of aluminum chloride were produced? (2 points) 2 Al + 6 HCl yields 2 AlCl3 + 3 H2 516 g AlCl3 774 g AlCl3 1030 g AlCl3 1550 g AlCl3
Answer:
1040
Explanation:
you can use the mole to mole ratios of aluminum chloride and hydrogen gas,you first have to find the number of moles of hydrogen gas..the number of moles of hydrogen gas are 11.7(23.4/2)
2AlCl3+3H2
2 : 3
x :11.7
3x/3=23.4/3
x=7.8g/mol
then find the number of grams of aluminum chloride
m=n×mr
=7.8×133.341
=1040g
I hope this helps and sorry if it's wrong
A 0.085 M solution of a weak acid has a pH of 2.68. Determine the Ka value for this acid.
Answer:
The answer for ka is 5.26x10^-5
Explanation:
Fill in 5.26x10^-5
Atom A and Atom B have the same number of protons and neutrons, but they do not have the same number of electrons. ASAP
Answer:
They will be considered ions of the same element.
Explanation:
Ions form from elements when they gain or loss an electron, causing the number of protons (positively charged) to be unequal to the number of electrons (negatively charged), resulting in a net charge.
If there are more electrons than protons (from an element gaining 1 or more electrons), the ion is negatively charged and is called an anion.
If there are more protons than electrons (via the loss of electrons), the ion is positively charged and is called a cation.
which statement best describes the polarity of the molecule Sil4
a. it is polar, because the bond polarities add together in a tetrahedral molecule
b. It is non-polar, because the bond polarities cancel each other out in a tetrahedral molecule
c. it is non-polar, because the bonds between silicon (si) and iodine (I) are not polar
d. it is polar, because the bond polarities add together in a trigonal-planar molecule
How many moles of oxygen are required to react completely with 5 mol C8H18?
Answer:
62.5 moles of O₂.
Explanation:
We'll begin by writing the balanced equation for the reaction. This is illustrated below:
2C₈H₁₈ + 25O₂ —> 16CO₂ + 18H₂O
From the balanced equation above,
2 moles of C₈H₁₈ reacted with 25 moles of O₂.
Finally, we shall determine the number of mole of O₂ needed to react with 5 moles of C₈H₁₈. This can be obtained as shown below:
From the balanced equation above,
2 moles of C₈H₁₈ reacted with 25 moles of O₂.
Therefore, 5 moles of C₈H₁₈ will react with = (5 × 25) / 2 = 62.5 moles of O₂.
Thus, 62.5 moles of O₂ is needed for the reaction.
what is electronic configuration?
Answer:
In atomic physics and quantum chemistry, the electron configuration is the distribution of electrons of an atom or molecule in atomic or molecular orbitals.
A student measures the volume of a small irregularly- shaped stone. Which apparatus must be used? a. a measuring cylinder containing water and a ruler only. b. a measuring cylinder containing water only. c. an empty measuring cylinder and a ruler only. d. a ruler only.
Answer:
a measuring cylinder containing water only.
Explanation:
If we want to measure the volume of an irregular object. We need a properly calibrated measuring cylinder filled with water of known volume.
The irregular object is now inserted into the measuring cylinder containing water and the change in the volume of water is noted. The volume of the irregular object is now obtained as;
New volume of water - initial volume of water.
Hence, only a measuring cylinder filled with water is required to measure the volume of a small irregularly- shaped stone.
Which of the following describes metallic character on the periodic table? Question 1 options: A) It increases as you move right to left within a period and down a group on the periodic table. B) It increases as you move left to right within a period and down a group on the periodic table. C) It increases as you move left to right within a period and up a group on the periodic table. D) It increases as you move right to left within a period and up a group on the periodic table.
Answer:
D
Explanation:
Metallic character decreases as you move across a period in the periodic table from left to right. This occurs as atoms more readily accept electrons to fill a valence shell than lose them to remove the unfilled shell. Metallic character increases as you move down an element group in the periodic table. This is because electrons become easier to lose as the atomic radius increases, where there is less attraction between the nucleus and the valence electrons because of the increased distance between them.
