2. Evaluate :
(i) 28 : 23
Answer:
28/23
Explanation:
28 : 23
this is written as ,
28/23
u can convert into simplest form but in this question u can't so leave it as it is.
Which best describes an alpha particle that is emitted during nuclear decay?
A. A helium nucleus
B. A hydrogen nucleus
C. An electron
D. A positron
Answer:
A helium nucleus
Thre types of radiation
Alpha: Helium nucleus
Beta: Electron
Gamma: Gamma rays
Why does platinum metal make a good catalytic surface for reactant molecules?
It causes reactant molecules to be less reactive.
It strengthens bonds between reactant molecules.
It prevents products from breaking away from the surface.
It holds reactant molecules in a good position for them to react.
Answer:
it holds reactant molecules in a good position for then to react
Answer:
D. It holds reactant molecules in a good position for them to react.
Explanation:
Got a 100 on e2020.
what does the second law of thermodynamics say about entropy
Answer:
The entropy and the systems surrounding it tend to increase.
Answer: The entropy in a system and its surroundings tends to increase.
Explanation:
3.3.2 Quiz: Entropy (a p e x)
Which group on the periodic table contains chemical elements that are shiny and conduct electricity?
A.
Metalloids
B.
Nonmetals
C.
Representative elements
D.
Metals
Can someone please solve this for me and explain it
83.3% yield
Explanation:
First, we need to convert 240 g of [tex]Fe_{2}O_{3}[/tex] into moles:
[tex]240 \:g \:Fe_{2}O_{3} \:\times(\frac{1\:\text{mol}\:Fe_{2}O_{3}}{159.69\: \text {g}\:Fe_{2}O_{3}})[/tex]
[tex]=1.50 \:\text{mol}\:Fe_{2}O_{3}[/tex]
Next, find the theoretical Fe yield using molar ratios.
[tex]1.50 \: \text {mol} \: Fe_{2}O_{3}\: \times (\frac{2\: \text{mol} \: Fe}{1 \:\text{mol} \: Fe_{2}O_{3}})[/tex]
[tex] = 3.00 \: \text{mol} \: Fe[/tex]
Then convert this back into grams:
[tex]3.00 \: \text{mol} \:Fe \times (\frac{55.845 \: \text{g} \: Fe}{1 \: \text{mol} \: Fe}) = 168 \: \text{g} \: Fe[/tex]
Note that actual yield is only 140 g Fe so percentage yield is
[tex]\dfrac{140\:\text{g}\:Fe}{168\:\text{g}\:Fe} \times 100[/tex]%= 83.3%
83.3%
The answer is 83.3%
BRAINILIEST PLEASEAt 40km up in the atmosphere the pressure is 3.8 kPa. I release a balloon with a volume of 30.0
liters from sea level. The balloon ascends up into to atmosphere 40 km. What will be the new
volume of the balloon, assuming no change in temperature?
Answer in liters
A sample of gas occupies a volume of 55.3 L, has a temperature of 23.3 °C and a pressure of .658 atm. Calculate the number of moles of gas which are present in the sample. R= .0821 atm L/mol K
Answer: The number of moles of gas which are present in the sample are 1.49 mol.
Explanation:
Given: Volume = 55.3 L
Temperature = [tex]23.3^{o}C[/tex] = (23.3 + 273) K = 296.3 K
Pressure = 0.658 atm
Formula used is as follows.
PV = nRT
where,
P = pressure
V = volume
n = no. of moles
R = gas constant = 0.0821 L atm/mol K
T = temperature
Substitute the values into above formula as follows.
[tex]PV = nRT\\0.658 atm \times 55.3 L = n \times 0.0821 L atm/mol K \times 296.3 K\\n = \frac{0.658 atm \times 55.3 L}{0.0821 L atm/mol K \times 296.3 K}\\= \frac{36.3874}{24.32623}\\= 1.49 mol[/tex]
Thus, we can conclude that the number of moles of gas which are present in the sample are 1.49 mol.
A molecule has four bonded atoms around a central atom. The central atom does not have any lone pairs of electrons. What is the geometry of the molecule?
Answer:
Tetrahedral. Tetra- signifies four, and -hedral relates to a face of a solid; “tetrahedral” literally means “having four faces. ” This shape is found when there are four bonds all on one central atom, with no lone electron pairs. In accordance with the VSEPR theory, the bond angles between the electron bonds are 109.5o ...
There are two characteristics of molecules, one is geometry and other is shape. Shape is excluding lone pair surrounding the central element and geometry is including the lone pair. Therefore, the geometry of given molecule is tetrahedral.
What is VSEPR theory?
VSEPR stands for valence shell electron pair repulsions. VSEPR theory is used to predict the shape and geometry of molecules on the basis of valence electrons pairs that are present around the central element of the molecule.
According to VSEPR theory, Lone pair lone pair repulsion is greater than bond pair bond pair repulsion. There are so many limitations of VSEPR theory. There is a repulsion between bond pair electrons and lone pairs present on the central element.
A molecule has four bonded atoms around a central atom. The central atom does not have any lone pairs of electrons. The geometry of such molecule is Tetrahedral. Geometry does not include lone pair on central atom.
Therefore, the geometry of given molecule is tetrahedral.
To know more about VSEPR theory, here:
https://brainly.com/question/19582124
#SPJ6
ChemBonding9. In ammonium chloride NH4Cl, the bonding between NH4+ and chloride ion Cl− is _______.
options:
ionic
polar covalent
nonpolar covalent
I have oxygen gas at 2 L and 2 atm. At what pressure is the oxygen gas if my volume decreases to 1 L?
Answer: The oxygen gas has a pressure of 4 atm if my volume decreases to 1 L.
Explanation:
Given: [tex]V_{1}[/tex] = 2 L, [tex]P_{1}[/tex] = 2 atm
[tex]V_{2}[/tex] = 1 L, [tex]P_{2}[/tex] = ?
Formula used to calculate the new pressure is as follows.
[tex]P_{1}V_{1} = P_{2}V_{2}[/tex]
Substitute the values into above formula as follows.
[tex]P_{1}V_{1} = P_{2}V_{2}\\2 atm \times 2 L = P_{2} \times 1 L\\P_{2} = 4 atm[/tex]
Thus, we can conclude that the oxygen gas has a pressure of 4 atm if my volume decreases to 1 L.
Thompson's experiments with cathode ray tube lead to the invention of what?
Answer:
Thompson's experiments with cathode ray tube showed that every atom contains a small amount of negatively charged subatomic particles. Thomson proposed the plum pudding model of the atom.
Explanation:
7. You have 1.5x1024 atoms of iron. How many moles do you have?
Answer:
2.49moles
Explanation:
To calculate the number of moles (n), of iron (Fe) in 1.5 × 10²⁴ atoms, we divide the number of atoms by Avogadro's number (6.02 × 10²³).
That is, n = N ÷ nA
Where;
n = number of moles (mol)
N = number of atoms
nA = Avogadro's constant
n = 1.5 × 10²⁴ ÷ 6.02 × 10²³
n = 1.5/6.02 × 10(²⁴ - ²³)
n = 0.249 × 10¹
n = 2.49moles
Please I need an explanation on the relationship between concentration and volume of reacting substances
Answer:
when d volume of a substance is high, the concentration is gonna b low...
Jus lyk putting much water in just a cube of sugar
Explanation:
So lower volume, higher concentration
Diseña un procedimiento que te ayudaría a obtener agua en el desierto usando como fundamento la destilación?
Answer:b
Explanation:
I searched it
What is the mass of 0.125 moles of tin sulfate (SnSO4)?
Answer:
26.85 grams
Explanation:
The formula for mole calculations is number of moles = given mass/gram-formula mass.
The number of moles is given to us, which is 0.125.
The gram formula mass of SnSO4 is about 214.77.
Plug in the values we have into the equation. It should look like this:
0.125 = x / 214.77
Solve for x by multiplying 214.77 and 0.125. The answer should be about 26.85 grams.
Cheese is an example of Solid in gas colloid Liquid in gas colloid Solid in liquid colloid Liquid in solid colloid
Which statement is true for most autotrophic organisms?
A. They carry on extracellular digestion of nutrients before they ingest them.
B. They synthesize organic molecules from inorganic molecules.
C. They obtain organic molecules from heterotrophic organisms.
O O
D. They require no external energy source.
omg yees
eExplanation:
4. A piece of metal weighing 0.0713 g was placed in a eudiometer containing dilute aqueous HCl. After the metal fully dissolved, 23.5 mL of hydrogen gas was collected by displace-ment of water and a 400 mm column of water was observed. The water temperature was 258C and the barometric pressure was 758.8 mm Hg (torr). Refer to the Introduction and data sheet to solve the following problems. a) What is the vapor pressure of the water vapor in the column? (Consult Appendix E.)
Complete Question
4. A piece of metal weighing 0.0713 g was placed in a eudiometer containing dilute aqueous HCl. After the metal fully dissolved, 23.5 mL of hydrogen gas was collected by displace-ment of water and a 400 mm column of water was observed. The water temperature was 258C and the barometric pressure was 758.8 mm Hg (torr). Refer to the Introduction and data sheet to solve the following problems.
a) What is the vapor pressure of the water vapor in the column? (Consult Appendix E.)
b) What is the pressure of the water column expressed in mm Hg (torr)? The density of mercury is 13.6 g/mL.
c) Calculate the pressure of the hydrogen gas above the water in the column.
d) Calculate the volume occupied by the hydrogen gas at STP.
Answer:
a) [tex]25\textdegree C=23.8 torrs[/tex]
b) [tex]P_w=758.8[/tex]
c) [tex]P_w=758.8=735torr[/tex]
d) [tex]V_2=20.82mL[/tex]
Explanation:
From the question we are told that:
Metal weight [tex]M_m=0.0713g[/tex]
Volume Hydrogen [tex]V_h=23.5mL[/tex]
Displace-ment Column of water 400 mm column of water
Temperature [tex]T =258\textdegree C[/tex]
Barometric Pressure [tex]p=758.8mmHg[/tex]
Vapour Pressure of water at [tex]25^oC[/tex]
Generally from (Consult Appendix E.)
a)
Va-pour Pressure of water at
[tex]25\textdegree C=23.8 torrs[/tex]
b)
Pressure of Water column
[tex]P_w=758.8[/tex]
c) Pressure of Water column (Consult Appendix E.)
[tex]P_w=758.8=735torr[/tex]
d)
Generally the equation for ideal gas is mathematically given by
[tex]\frac{p_1v_1}{T_1}=\frac{p_2v_2}{T_2}[/tex]
Therefore
[tex]V_2=\frac{p_1V_1T_2}{T_1p_2}[/tex]
[tex]V_2=\frac{735*23.5*273}{298*760}[/tex]
[tex]V_2=20.82mL[/tex]
An oxygen atom has 8 protons. What number of neutrons would make an
oxygen atom most stable?
A. 10
B. 6
C. 12
D. 8
D. 8
Hope this helps! :)
______________
Answer:
D: 8 neutrons would make it most stable
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
E. Give reasons
1. Oxygen is a diatomic element.
3. The valency of sodium is one.
F. Differentiate between
1. electrovalent bond and covalent bond
2. acidic radical and basic radical
Answer:
the valency of sodium is one because sodium loses 1 electron to become stable
m%of solution containing 100 gram of NaCl dissolved in 500g of water
Answer:
16.7 %(m/m)
Explanation:
The percent by mass of a solution (% m/m) is defined as 100 times the ratio of the mass of solute (The substance in the lower amount, NaCl) and the mass of the solution = Mass solute + Mass Solvent (water).
Mass Solution:
100g NaCl + 500g water = 600g solution
Mass Percent:
100g NaCl / 600g solution * 100
= 16.7 %(m/m)
Complete the table by writing the name or formula of each compound and the type of bonding that it uses. You may refer to this list of polyatomic ions.
Explanation:
Dinitrogen monoxide: covalent bond
copper(||) hydroxide: ionic bond
Butane: Covalent Bond
Answer
Disulfur decafluoride S2F10 covalent
calcium sulfide CaSO3 ionic
Diphosphorus tetraiodide P2I4 ionic
dinitrogen monoxide N2O ionic
Aluminum chloride AlCl3 covalent
copper(II) hydroxide Cu(OH)2 ionic
barium sulfate BaSO4 covalent
butane C4H10 covalent
Explanation:
edmentum
help me with this attachment please
Answer:
See explanation
Explanation:
Let us recall that the basic rule in writing balanced chemical reaction equations is that the number of atoms of each element on the right hand side of the reaction equation is the same of the number of atoms of the same element on the left hand side of the reaction equation.
The reaction of red hot iron and steam is written as follows;
3Fe + 4H2O → Fe3O4 + 4H2.
The decomposition reaction of ammonium dichromate is written as;
(NH4)2Cr2O7 → N2 + Cr2O3 + 4H2O
Reaction of aluminium, sodium hydroxide and water is as follows,
2Al + 2NaOH + 2H2O ----> 2NaAlO2 + 3H2
Reaction of potassium bicarbonate with sulphuric acid;
2KHCO3 + H2SO4 -------> K2SO4 + 2H2O + 2CO2
Reaction of zinc and sodium hydroxide is as follows;
Zn + 2NaOH→Na2ZnO2 + H2
Calculate the number of O atoms in 0.364 g of CaSO4 · 2H2O
Answer:
= 7.66 x 10²¹ oxygen atoms in 0.364 grams of CaSO₄·2H₂O
Explanation:
For problems like this posting, one needs an understanding of the following topics:
The definition of the mole
1 mole of substance = mass in grams of substance containing 1 Avogadro's Number ( = 6.023 x 10²³ ) of particles of the specified substance. This is generally one formula weight of the substance of interest. From this, the following equivalent relationships should be memorized:
1 mole = 1 formula weight = 1 mole weight (g)= 6.023 x 10²³ particles
Converting grams to moles:
Given grams => moles = grams/gram formula wt
Converting moles to grams:
Given moles => grams = moles x gram formula wt
_________________________________________________________
Calculate the number of O atoms in 0.364 g of CaSO₄ · 2H₂O.
Given mass CaSO₄ · 2H₂O = 0.364 grams
Formula Wt CaSO₄ · 2H₂O = 172 g/mole
moles CaSO₄ · 2H₂O = mass CaSO4 · 2H2O / formula Wt. CaSO₄ · 2H₂O
= 0.364 g CaSO₄·2H₂O / 172 g CaSO4·2H2O
= (0.364/172) mole CaSO₄·2H₂O
= 2.12 x 10⁻³ mole CaSO₄·2H₂O
∴ number of Oxy (O) atoms in 0.364 grams CaSO₄·2H₂O
= (2.12 x 10⁻³ mole CaSO₄ · 2H₂O)(6.023 x 10²³ molecules CaSO₄· 2H₂O/ mole)
= 1.276876 x 10²¹molecules CaSO₄· 2H₂O CaSO₄2H₂O
= 1.276876 x 10²¹ molecules CaSO₄· 2H₂O x 6 oxygen atoms / molecule
= 7.661256 x 10²¹ oxygen atoms in 0.364 grams of CaSO₄·2H₂O
= 7.66 x 10²¹ oxygen atoms in 0.364 grams of CaSO₄·2H₂O
Which of these is a measure of the average kinetic energy of the molecules of a material? A.heat B.temperature C.thermal energy D.bonding energy
Answer:
b temperature
Explanation:
Temperature is a measure of the average kinetic energy of the particles in a substance
©
What is the maximum number of electrons that can occupy a box in an orbital filling diagram at any
energy level?
2
6
8
14
Answer:
2
Explanation:
Electronegativity6. Which one of the following bonds is the least polar one?
options:
C-F
C-Cl
C-Br
C-I
Why do we need to know these organic molecules?
Are they important to living things?
Answer:
Organic molecules are important to living things because life is based on the properties of carbon.
Properties of Carbon
Carbon is an important element because it can form four covalent bonds.
Carbon skeletons can vary in length, branching, and ring structure.
The carbon skeletons contain the functional groups that are involved in biochemical
Explanation:
Hope it helps
