Answer:
pH
7.0 = neutral.
(7–14) = basic
(0–6) = acidic
Explanation:
The electron configurations of two unknown elements x and y are shown. X: 1s2 2s2 2p6 Y: 1s2 2s2 2p6 3s2 3p6 Which statement is most likely correct about the two elements? A) They will react because X can give up two electrons B) They will react because X and Y can share two pairs of electrons to become stable C) They will not react because both have a complete outermost shell and are stable D) They will not react because both will give up one electron. to become stable.
Answer:
B) They will react because X and Y can share two pairs of electrons to become stable
Explanation:
The electron configurations of two elements x and y are given :
X: 1s2 2s2 2p6
Y: 1s2 2s2 2p6 3s2 3p6
The statement that is true for both the elements is that, they both will react as they both can share two pairs of electrons to become stable.
To become stable the outermost shell or p orbital should have 8 electrons, so element X can gain 2 atoms to become stable.
Element Y can also react as it can also share two atoms to fulfill its 3p orbital and will stable.
Hence, the correct option is "B".
You combine 13 g of magnesium with 5 g of nitrogen to form a compound.
What is the mass percent of nitrogen in the compound?
Answer:
[tex]\large \boxed{28 \, \% }[/tex]
Explanation:
magnesium + nitrogen ⟶ Product
13 g 5 g
Mass of product = 13 g + 5 g = 18 g
The product contains 5 g of nitrogen .
[tex]\text{Percent N} = \dfrac{\text{5 g}}{\text{18 g}} \times \, 100\% = \mathbf{28 \, \%}\\\text{The percent by mass of nitrogen is $\large \boxed{\mathbf{28 \, \% }}$}[/tex]
For the α anomer of a D-sugar, the anomeric hydroxyl in a Haworth projection Group of answer choices has an upward projection (on the same side as the terminal CH2OH group). has a downward projection (on the opposite side from the terminal CH2OH group).
Answer:
The answer is "choice 2".
Explanation:
Its glycosidic fruit juice facility would be a chromosomal hydrogen bond and an aldehyde (or acetone) team generated from the intramolecular creation of the acetals (or ketal).
Its two heterocycles created at the anomeric core from of the 2 potential stereochemical are named anomers, that's why choice "has a downward projection (from terminal CH2OH party on the opposite side)" is correct.
If the external vapor pressure is 2.0 atm , what is the vapor pressure of the water at its boiling point?
Answer:
22
Explanation:
22
The activation energy (E*) for 2N2O ---> 2N2 + O2 is 250 KJ. If the k for this reaction is 0.380/M at 1001oK, what will k be at 298oK? What will the half-life be at both temperatures?
Answer:
Explanation:
GIven that:
The activation energy = 250 kJ
k₁ = 0.380 /M
k₂ = ???
Initial temperature [tex]T_1 =[/tex] 1001 K
Final temperature [tex]T_2 =[/tex] 298 K
Applying the equation of Arrhenius theory.
[tex]In \dfrac{k_2}{k_1 }= \dfrac{Ea}{R}( \dfrac{1}{T_1 }- \dfrac{1}{T_2})[/tex]
where ;
R gas constant = 8.314 J/K/mol
[tex]In \dfrac{k_2}{0.380 }= \dfrac{250 * 10^3}{8,314}( \dfrac{1}{1001 }- \dfrac{1}{298})[/tex]
[tex]In \dfrac{k_2}{0.380 }= -70.8655[/tex]
[tex]\dfrac{k_2}{0.380 }= e^{-70.8655}[/tex]
[tex]\dfrac{k_2}{0.380 }= 1.67303256 \times 10^{-31}[/tex]
[tex]{k_2}= 1.67303256 \times 10^{-31} \times {0.380 }[/tex]
[tex]{k_2}= 6.3575 \times 10^{-32}[/tex] /M .sec
Half life:
At 1001 K.
[tex]t_{1/2} = \dfrac{In_2}{k_1}[/tex]
[tex]t_{1/2} = \dfrac{0.693}{0.38}[/tex]
[tex]t_{1/2} =[/tex] 1.82368 secc
At 298 K:
[tex]t_{1/2} = \dfrac{0.693}{6.3575 \times 10^{-32}}[/tex]
[tex]t_{1/2} =1.09 \times 10^{31} \ sec[/tex]
25. Which answer best describes the continental rise? area of land that drops toward deep ocean basins 75 mile shallow flat area just off coastlines thick deposits of sediments carried off of the shelf the surf area along coastlines
Answer:
Thick deposits of sediments carried off of the shelf
Explanation:
The continental rise is a thick deposit of sediments that accumulate between the continental slope and the abyssal plain
A is wrong. The area of land that drops toward the deep ocean basins is the continental slope.
B is wrong. The 75-mile shallow flat area just off coastlines is the continental shelf.
D is wrong. The surf area along coastlines is the surf zone .
Calculate the pH of a solution obtained by mixing 477 mL of 0.17 M hydrochloric acid with 253 mL of M lithium hydroxide. Assume the combined volume is the sum of the two original volumes.
Answer:
pH = 0.984
Explanation:
Molarity LiOH = 2.1x10⁻²M
HCl will react with LiOH as follows:
HCl + LiOH → H₂O + LiCl
1 moles of HCl reacts per mole of LiOH
Moles of each reactant in solution are:
HCl = 0.477L ₓ (0.17mol / L) = 0.08109 moles HCl
LiOH = 0.253L ₓ (2.1x10⁻² mol / L) = 5.313x10⁻³ moles of LiOH.
That means LiOH is the limiting reactant and excess moles of HCl that will remain in solution are:
0.08109 mol - 0.005313mol = 0.0758 moles HCl
As HCl dissociates in water as H⁺ and Cl⁻ ions, you will have in solution 0.0758 moles of H⁺
pH = -log [H⁺] and [H⁺] = moles H⁺ / L of solution.
Volume of the mixture in liters is: 0.477L + 0.253L = 0.730L.
That means [H⁺] is 0.0758 moles of H⁺ / 0.730L = 0.1038M
Replacing:
pH = -log [H⁺]
pH = -log [0.1038]
pH = 0.984To make a table of elements, dmitri
The question is incomplete, the complete question is;
To make a table of the elements, dimitri Mendeleev sorted the elements according to their?
Answer:
Atomic weights
Explanation:
Dimitri Medeleeve is a Russian scientist who worked assiduously on the project of developing a system of classifying all the elements. His periodic table was filled with spaces as many atoms weren't yet discovered. 'Eka' prefix was used to name some elements whose properties closely resembled that of their predecessors in Mendeleev's system of classification.
The dependence of the atomic properties on the weight of the atom was the basis for Mendeleeves' original classification. According to Medeleeve, elements having similar chemical properties are also expected to have similar atomic weights and their atomic weights was found to increase regularly.
The Mendeleeve concept of periodic arrangement of elements is the closest precursor of the modern periodic table as it is used in chemistry. Mendeleev arranged the elements in order of increasing relative atomic mass .
how many different d orbits are within the 3d sublevel
Answer:
Its 5
Explanation:
25g ice crystals are taken in a beaker and inserted a thermo meter into it and slowly heated. Answer the following questions based on the above experiment.
a) At what temperature ice starts melting?
b) At 50 0 C is reached, what is the physical state of ice?
c) At 100 0 C is reached the boiling point of substance is not rising for some time. What is the reason for it?
d) What is the boiling point of the substance?
e) What is physical state of the substance above 100 degree C?
Answer:
a) 0°C
b) liquid
c) The energy supplied at 100°C is utilized in breaking the intermolecular forces in the liquid.
d) 100°C
e) gas
Explanation:
There are three States of matter; solid, liquid and gas. If we start heating 25g of ice in a beaker with a thermometer inserted into it, the ice will change from solid to liquid and finally to gas as the temperature increases.
At 0°C, the solid ice begins to melt and remains liquid between 0°C-100°C. This is called the liquid range of water. At 100°C, the heat supplied does not lead to further rise in temperature. The energy supplied is rather utilized in breaking the intermolecular forces in the liquid. This is known as the latent heat of vaporization. Above 100°C, the liquid is changed to vapour. Water vapour is commonly called steam.
Help me pls!
What is heliuim?
Answer:
it's a chemical Element
Explanation:
symbol He
atomic number 2.
During which two minute time period is the temperature of the water changing fastest? Select one: a. 0-2 minutes b. 2-4 minutes c. 4-6 minutes d. 6-8 minutes Clear my choice
Answer:
b. 2-4
Explanation:
Look at the slope of the line, between 0-2 and 4-6 the slope is only 10, but between 2-4 the slope is 20, so that's when the temperature is changing the fastest. In the same time it took for the water to increase by 20 degrees between 0-2 and 4-6, the temperature of the water increased by 40 degrees between 2-4 so that's when the change is the fastest.
PLEASE HELP A woman travels to Canada where milk is sold in liters. She wants to buy enough milk at the grocery store to last 5 days and she knows at home she uses 0.75 gallons per week. How many liters must she buy?
Answer:
About 2 liters
Explanation:
Since 1 gallon equals 3.785 liters, you figure out how many liters per week she uses by 3.785 x 0.75 which is 2.83875. Then divide that by 7 which is 0.405535 liters per day. Then multiply that by 5 days which is 2.027 liters in 5 days.
how many moles are in 8.5 x 10^25 molecules of CO2
Answer:
the answer is 5.1 1049 mol.
Calculate mole fraction of ethylene
Glycol in solution
containing 20% g C2H6O2 by mass.
Answer:
Explanation:
20% of C2H6O2
since its a solution, this means that it has 20g of ethylene glycol and the rest is water.
Molar mass of C2H6O2 = (12 x 2) + (1 x 6) + (2 x 16)
= 62
mole = mass/molar mass
Moles of C2H6O2 = 20/62
= 0.322 mol
Moles of water = 80/18
= 4.444 mol
mole fraction = mol of solute / tatal mol of solution
Mole fraction of ethylene glycol = 0.322/(0.322 + 4.444)
= 0.068
Mole fraction of water = 1 - 0.068
= 0.932
How many moles are in 10.23 g of PO4-3? How many moles are 8.25 x 10^28 molecules of Na2CO3? What is the mass of 6 moles of CH2O? How many formula units are in 6.34 g of NaCl? How many ions are in 0.25 moles of Cu+2? How many grams are in 3.4 x 10^24 molecules of CH4? How many moles are in 10 mL of water (density of water = 1 g/mL)? (sorry for so many questions in one)
Answer:
1) 0.1077 moles
2) 137043.2 moles
3) 180.186 grams
4) 6.53×10²² molecules or formula units
5) 1.505×10²³ ions
6) 90.626 grams
7) 0.555 moles
Explanation:
1) The number of moles, n = Mass of the substance/(Molar mass of the substance)
The molar weight of PO₄⁻³ is 94.971 g/mol
The number of moles in 10.23 g of PO₄⁻³ is n =10.23/94.971 = 0.1077 moles
The number of moles in 10.23 g of PO₄⁻³ = 0.1077 moles
2) The number of molecules of Na₂CO₃ in one mole of Na₂CO₃ is given by the Avogadro's number, [tex]N_A[/tex] = 6.02 × 10²³ molecules
Therefore, the number of moles in 8.25 × 10²⁸ molecules of Na₂CO₃ is found by determining how many Avogadro's number of molecules are in 8.25 × 10²⁸ molecules of Na₂CO₃ as follows;
The number of moles in 8.25 × 10²⁸ molecules of Na₂CO₃ = (8.25 × 10²⁸)/(6.02 × 10²³) = 137043.2 moles
The number of moles in 8.25 × 10²⁸ molecules of Na₂CO₃ = 137043.2 moles
3) The molar mass of CH₂O = 30.031 g/mol
Therefore, the mass of 6 of CH₂O = 6 moles × 30.031 g/mol = 180.186 grams
The mass of 6 of CH₂O = 180.186 grams
4) The molar mass of NaCl = 58.44 g/mol
The number of moles of NaCl in 6.34 g of NaCl 6.34/58.44 = 0.1085 moles
1 formula unit of NaCl = 1 molecule of NaCl
The number of molecules in one mole of a substance = [tex]N_A[/tex] = 6.02 × 10²³
Therefore, the number of molecules in 0.1085 moles of NaCl = 6.02 × 10^(23) × 0.1085 = 6.53×10²² molecules or formula units
5) The number of ions per mole of any substance is give by Avogadro's number, [tex]N_A[/tex] = 6.02 × 10²³ ions,
The number of ions in 0.25 moles of Cu⁺² = 0.25×6.02 × 10²³ ions = 1.505×10²³ ions
The number of ions in 0.25 moles of Cu⁺² = 1.505×10²³ ions
6) The molar mass of CH₄ = 16.04 g/mol
The number of moles, n, in 3.4×10²⁴ = 3.4×10^(24)/(6.02×10^(23)) = 5.65 moles 5.65*16.04
The mass of 5.65 moles of CH₄ = 5.65 moles × 16.04 g/mol = 90.626 grams
The mass of 3.4×10²⁴ molecules of CH₄ = 90.626 grams
7) The density of water = 1 g/mL
The volume of the water 10 mL
The mass of the water = Volume × Density = 10 mL × 1 g/mL= 10 grams
The molar mass of water = 18.015 g/mol
The number of moles of water in 10 g of water = mass/(Molar mass) = 10/18.015 = 0.555 moles.
A stone bead and an iron bead are dropped into a cup of water. They both sink to the bottom of the cup. What can be said about these beads?Immersive Reader
Answer:
Both have densities greater than that of water
Explanation:
The ability of objects to either float or sink in a liquid depends on their relative densities.
If an object is denser than a liquid it will completely sink in it, but if the density of the object is less than that of the liquid, it will sink until the weight of liquid displaced is equal to the weight of the object, then it will finally float in that liquid.
In the case of the stone bead and iron beads dropped into a cup of water, hey both sank to the bottom because they are denser than water.
Plz solve mcqs#04 with full detailed.note
Answer:
The correct option is;
(B) 1 s², 2s², 2p⁶, 3s², 3p³
Explanation:
The electron configuration is the outline of the electron arrangement about a nucleus
In the systemic pattern of electron arrangement within an atom, there are, s, p, d, f orbitals
The maximum number of electrons in an s, p and d orbital = 2, 6, and 10 respectively
Based on Aufbau's principle the electrons are arranged based on the order of their energy level
The charge is presented by the number of electrons in the outermost shell, an element able to form an ion of charge of -3 will gain 3 electrons to complete its outermost shell
Among the options given, option B is the only option that has the capacity to take the electrons to complete the number of electrons in the p orbital outermost shell to 6 from 3, that is 3p³ + 3e⁻→ 3p⁶.
Answer the following questions:
1. Define a compound. State three points of evidence to show that sodium chloride is a compound.
2. When Iron powder and Sulphur powder were mixed together and heated strongly, a substance A was formed. When did. Hydrochloric acid was added to substance A, the gas B was evolved.
a) What is A and what type of substance is it?
b) Name the gas B. State one characteristic property of gas B.
c)Is the reaction of Iron and Sulphur powder a chemical change or a physical change.
Answer the question according to the class 9th student.
Answer:
1. A compound is a group of elements that cannot be separated by physical methods.
NaCl is a compound becuse it cannot be separated by physical methods.
It consists of postive and negative ions.
It can be separated only by chemical reactions.
2. (a) A is a mixture of iron and sulphur and it is in liq form.
(b) Gas B is hydrogen gas and it has sharp pungent irritating smell.
(c) It is a physical change.
Explanation:
Adrian loves the pancakes! The problem is, the recipe serves only six, and he has 540 people in his family (including aunts, uncles, and cousins). Now, he needs help increasing the recipe to feed his entire family. However, Adrian is particular - he insists on using only three significant figures with scientific notation.
Answer:
ingredient. U.s unit. SI unit. SI unit(540)
flour. 2cups. ²/6. 180cups = 1.8×10²
milk. 2cups. ²/6. 180cups. =1.8×10²
eggs. 2. ²/6. 180eggs. =1.8×10²
melted butter. ⅓cup ¹/18. 30cups. =3×10¹
sugar. 1spoon. ¹/6. 90spoons. =9×10¹
baking powder 2spoons ²/6. 180spoons. =1.8×10²
salt. ½spoon. ¹/12. 45spoons. =4.5×10¹
Explanation:
1) to get the SI unit divide the U.S unit by 6
example:eggs = 2÷6. =²/6
2) to get the SI unit for 540 people ,multiply the SI unit by 540.
example:eggs ²/6×540. = 180
3)convert the answers to scientific notation
example:eggs =180. =1.8×10²
Which of the following is the best explanation for why it is important to follow lab safety guidelines
a. Following laboratory safety guidelines prevents all lab accidents.
b. Following laboratory safety guidelines minimizes the chance of lab ac
C. Following laboratory safety guidelines prevents fires.
d. Following laboratory safety guidelines allows quick response during la
Please select the best answer from the choices provided
Answer:
B
Explanation:
The main aim of lab rules is to minimize the no of accidents
What is the molarity of 0.25 moles of FeCl3 dissolved in 120 ml of solution?
Answer:
Molarity = 2.0833 M (Approx)
Explanation:
Given:
Number of moles (n) = 0.25
Volume of solution = 120 ml = 0.12 L
Find:
Molarity
Computation:
Molarity = Number of moles (n) / Volume of solution.
Molarity = 0.25 / 0.12
Molarity = 2.0833 M (Approx)
An isotope of lead can be represented by the following symbol ²⁰⁷ 82 PB. From this symbol, it can be deduced that one atom of the isotope has: A) 82 neutrons B) 82 protons C) 125 protons D) 207 protons
Answer:
B) 82 protons
Explanation:
The number of protons for an element never change. 82 Is the atomic number for Pb which is how many protons it has. An isotope means it has more neutrons.
Which quantity can be calculated using the equation E=MC^2
Answer:
The energy needed to split an atom into separate protons, neutrons, and electrons
Explanation:
The equation E = MC^2 is developed by Einstein’s Special Relativity Theory
where,
E = Energy
M = mass
C = speed of the light
The energy should be measured in Joules i.e J
The mass should be measured in Kilogram i.e Kg
And, the speed of the light should be measured in meters per second i.e ms-1
The C should be squared
Now the energy is required to divided into three particles i.e protons, electrons and neutrons
It also needs to allocate the nucleus into distinct protons and neutrons that we called binding energy of nuclear
And if the energy is required to take off an electron from an atom we called the energy of ionization
And if the energy is required to add an electron to an atom so we called it affinity of electron
What happens to water 100°C as pressure is increased from 0.7 atm to 1.4 atm
Answer:
Explanation:
The graph shows the phase diagram of water . From it , it is clear that at 100°C water remains in equilibrium with water vapour and at this temperature , the vapour pressure is equal to one atm . So this must be boiling point of water.
At 0.7 atm pressure , boiling point must have been reduced . So when water is at 100°C , it must have been completely in vapour phase .
Now the pressure is increased to 1.4 atm . In this process of increase of pressure , the water in vapour state must have turned into liquid state as soon as the pressure increases beyond 1 atm . Beyond it its boiling point would have increased above 100°C so it can not remain in gaseous phase . At 1.4 atm , its boiling point would have increased to 110°C or so . Hence it must be in liquid phase because its temperature is below its boiling point at that pressure .
Hence water changes from gaseous phase to liquid phase when pressure changes from 0.7atm to 1.4 atm .
As defined by Aristotle, which one of the following is an element?
1. water 2. air 3. soil 4. none of them
Answer:
4
Explanation:
none of them
they are compounds and mixtures
Answer:
4. none of them
Explanation:
Water is a compound.
Air is a mixture.
Soil is a mixture.
None of them are elements.
A 2.5-liter sample of a gas has 0.30 mole of the gas. If 0.15 mole of the gas is added, what is the final volume of the gas? Temperature and pressure remain constant. 3.4 liters 3.8 liters 4.2 liters 4.7 liters
Answer:
3.75 ltrs
Explanation:
The final volume of the gas is 3.8L.
What is volume?Volume is the quantity of space occupied by a liquid, solid, or gas.
Using Avogadro's law.
Avogadro's Law:
According to Avogadro's law an equal volumes of all gases, at the same temperature and pressure, have the same number of molecules. For a given mass of an ideal gas, the volume and amount (moles) of the gas are directly proportional if the temperature and pressure are constant.V₁/n₁=V₂/n₂
Where V₁ = initial volume
V₂ = final volume
n₁ = initial amount of gas in moles
n₂ = final amount of gas in moles
Avogadro's Law explains when the temperature and pressure are kept constant, volume is directly proportional to gas amount in moles, which means when the volume increases, the amount of gas also increases.
V ∝ n
V₁/n₁ = V₂/n₂
V₁ = 2.5L, V₂ = ?, n₁ = 0.30 mol, n₂ = 0.45 mol
substituting the above values in the equation,
2.5L/0.30 mol = V₂/0.45 mol
V₂ = 1.125/0.30 mol
V₂ = 3.8L
Hence, 3.8L is the final volume of the gas.
To learn more about Avogadro's law here
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URGENT:
Do you switch charges for ionic or covalent bonds when naming them?
Answer:
ionic
Explanation:
The fact that a heat pump requires energy to move heat from a colder object (the outside of a house) to a hotter object (the inside of the house) is a real life observation of which thermodynamic law?
Answer:
The correct answer is - the second law of thermodynamics.
Explanation:
The second law of thermodynamics says that the in all heat energy exchange or transfer, and if there is no gain or lose of energy in a system, the potential energy of the particular state in that system will less than that of initial state of the system in any case.
It also suggests that the processes deals with the conversion of the heat energy are irreversible and the energy can be transfer from lower temperature system to higher temperate system without adding energy.
Thus, The fact that a heat pump requires energy to move heat from a colder object to a hotter object is a real life example of the second law of thermodynamics.
An antacid tablet has a pH of about 9.5 which
means it is considered to be in the _____
range.
Acidic or basic
Answer:
Basic
Explanation:
The pH scale is a scale that tells us about the concentration of hydrogen ions in a solution.
Acids have many hydrogen ions. Acids have a pH of less than 7.
Bases have fewer hydrogen ions and more hydroxide ions. Bases have a pH of less than 14.
If the solution has a pH of exactly 7, then it is pure water. Water has the same concentration of hydrogen and hydroxide ions.
The antacid tablet has a pH of roughly 9.5 Since this is less than 14, but not equal to or less than 7, this must be an base. Therefore, it is considered to be in the basic range.
Answer:
9.5 is a base
Explanation:
A ph of less than 7 is an acid
7 is neutral
7 to 14 is a base
9.5 is a base