After 7 half-lives, 0.78% of a substance remains. This is calculated by taking 0.5 to the power of 7, as each half-life represents a 50% reduction of the remaining substance from the previous amount.
To determine what percentage of a substance remains after 7 half-lives, you can calculate the remaining quantity using the principle that after each half-life, only 50% of the substance remains from the previous amount. So after 1 half-life, 50% remains; after 2 half-lives, 25% remains (which is 50% of 50%); and this process continues.
To find the remaining percentage after 7 half-lives, you would calculate (0.5)^7. That means you take 0.5 (half of the substance) and multiply it by itself 7 times. The calculation will look like this: 0.5 x 0.5 x 0.5 x 0.5 x 0.5 x 0.5 x 0.5 = 0.0078125, which is 0.78125%. You can round this to 0.78%, which is the closest answer to the options given and would be the correct choice.
Which of these did your answer include?
Each hydrogen atom is bonded to the oxygen atom with a single bond.
The oxygen atom has two lone pairs.
The molecule is bent.
Oxygen is more electronegative than hydrogen.
Each O-H bond is polar.
The molecule is asymmetrical.
The asymmetry and the polar bonds produce an overall molecular dipole.
The oxygen atom has a partial negative charge, and the hydrogen atoms have a partial positive
charge.
The oxygen atom has a partial negative charge and the Hydrogen atoms have a partial positive charge
The O2 atoms have a covalent bonding and are attracted to the electrons more strongly.
The sharing of the electrons gives them water molecules a slightly negative change near the O2 atom. A slight positive change near the H2. Hence the option D is correct.Learn more about the did your answer includes.
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This diagram shows the shift in the spectrum for hydrogen light from several different sources in the universe compared to a laboratory reference. What is the best argument you can make from this data?
A) More distant galaxies are hotter than nearby stars
B) More distant galaxies are moving toward us faster than a nearby star
C) More distant galaxies are moving at the same rate as nearby stars
D) More distant galaxies are moving away faster than nearby stars
Answer:
Many stars and distant galaxies move at varying speeds compared to each other.
Explanation:
All statements are contradictory, so play it safe and declare different energy levels.
Answer:
I think the answer is A) More distant galaxies are hotter than nearby stars
Explanation:
Hope this helps :)
Some chemical reactions take a very long time to go to completion or cannot be directly measured. Which law allows one to use two or more thermochemical equations to
calculate the heat of a reaction indirectly?
-Pascal's Principle
-Hess's law of heat production
-Hess's law of heat division
-Hess's law of heat summation
Answer:
D
Explanation:
If you add two or more thermochemical equations to give a final equation, then you also add the heats of reaction to give the final heat of reaction
How many moles of helium are in a Superman ballon of volume 8.5 L at 92.3 kPa and 287 K?
Answer : The number of moles of helium are, 0.329 mol.
Explanation :
To calculate the moles of helium gas we are using ideal gas equation.
[tex]PV=nRT[/tex]
where,
P = Pressure of [tex]He[/tex] gas = 92.3 kPa = 0.911 atm
V = Volume of [tex]He[/tex] gas = 8.5 L
n = number of moles [tex]He[/tex] = ?
R = Gas constant = [tex]0.0821L.atm/mol.K[/tex]
T = Temperature of [tex]He[/tex] gas = 287 K
Now put all the given values in above equation, we get:
[tex]0.911atm\times 8.5L=n\times (0.0821L.atm/mol.K)\times 287K[/tex]
[tex]n=0.329mol[/tex]
Thereofore, the number of moles of helium are, 0.329 mol.
What type of wave is shown below?
A. Transverse wave
B. Longitudinal wave
C. Combined wave
D. Sound wave
Answer:
It's C (combined wave)
Explanation:
Manganese dioxide (MnO2(s), Delta.Hf = –520.0 kJ) reacts with aluminum to form aluminum oxide (AI2O3(s), Delta.Hf = –1699.8 kJ/mol) and manganese according to the equation below. 3 upper M n upper O subscript 2 (s) plus 4 upper A l (s) right arrow 2 upper A l subscript 2 upper O subscript 3 (g) plus 3 upper M n (s). What is the enthalpy of the reaction? Use Delta H r x n equals the sum of delta H f of all the products minus the sum of delta H f of all the reactants.. –1,839.6 kJ –1,179.8 kJ 1,179.8 kJ 1,839.6 kJ
Answer:
-1,839.6
Explanation:
The enthalpy of the reaction between Manganese dioxide and aluminum to produce aluminum oxide and manganese is -1,839.6 kJ, calculated using the formula for ΔH reaction incorporating the enthalpies of formation of the reactants and products.
Explanation:The enthalpy of the reaction for Manganese dioxide and aluminum to produce aluminum oxide and manganese can be calculated using the formula ΔHrxn = Σ ΔHf products - Σ ΔHf reactants. Here, the ΔHf for MnO2 is -520.0 kJ and for Al2O3 is -1699.8 kJ/mol. The balanced reaction involves 3 moles of MnO2 and 2 moles of Al2O3, so applying this to our equation: ΔHrxn = [2(-1699.8 kJ) + 3(0 kJ)] - [3(-520.0 kJ) + 4(0 kJ)], because the formation of a pure element in its standard state, like solid Mn, is zero. Hence, the ΔHrxn calculates to be -1,839.6 kJ.
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Question 9
1 pts
A gas of 3.4 moles occupies a volume of 0.046 Lat 298 K. What is the pressure
in kPa?
O 4.40 x 100 kPa
O 9.45 x 103 kPa
O 6.1 x 102 kPa
O2.1x 105 kPa
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Answer:
2.1 x 105 kPa
Explanation:
Answer:
2.1 x 105 kPa
Explanation:
just took a quiz got it right so good luck!! :)
The cell wall of a fungi is made of
what?
A) cellulose
B) chitin
C) cytoplasm
Answer:
B. Chitin
Explanation:
Simple, chitin
Can someone please help me
Answer:
c
Explanation:
Which process takes the
longest to occur?
freezing
melting
boiling
heating the solid
What groups of elements do not have a charge and why
Answer:
Noble gases because they have a full outer shell of electrons.
Explanation:
Noble gases usually called inert gases are generally non reactive gases. They belong to group 18 elements.They tend to not gain the electron or not give up a electron as they have full valence shells. Because they already have full valence shell and therefore full outer energy level, they are very stable and hardly react with any other elements.
Write the reduction reaction of glucose to form sorbitol. List and explain the side effects caused by too much sorbitol consumption.
Answer:
The product of reduction of glucose is sorbitol
The side effects caused by too much sorbitol consumption include: Diarrhea, Nausea, stomach discomfort
Explanation:
Please find attached the reaction of glucose with NADPH to produce sorbitol
Answer:
Glycytols or alditols (also called alcoholic sugars) are characterized by being a set of sweet-tasting organic chemical compounds of the polyol family. These compounds are chemically considered hydrogenated carbohydrates whose carbonyl group (aldehyde, ketone, sugar reducer) has been reduced to a primary or secondary hydroxyl group (i.e. an alcohol). Alcoholic sugars have the general formula H (HCHO) n + 1H, while sugars have H (HCHO) nHCO. Food applications are used in modifications as sweeteners to replace sugar (sucrose). Glycytols contain very low calorie contents, and their low fermentability makes them non-cariogenic, that is why it can be found in the package leaflet of some pediatric toothpastes, or Asian chewing gum itself.
Explanation:
When taking too much sorbitol (between 20 to 50 grams) it can have many negative effects by causing gas and abdominal pain and even become a very powerful laxative that even causes diarrhea.
In diabetic patients, it is usually used as a sweetener and prevents spikes in blood glucose because it generates the accumulation of water in the walls of the intestines, delaying the absorption of glucose
Humans first appeared in the _____ period.
A) Mesozoic
B) Paleozoic
C) Jurassic
D) Cenozoic
Answer:
They first appeared in the fossil record around 66 million years ago, soon after the Cretaceous–Paleogene extinction event that eliminated about three-quarters of plant and animal species on Earth, including most dinosaurs.
Explanation:
Answer:
A or b I learned this in history
How much heat is released when 0.762 mol of copper cools
from 81.6°C to 52.2°C?
Answer:
548.089 J
Explanation:
-The molar mass of copper is 63.546 grams.
-We obtained the mass of 0.762 moles of copper:
[tex]mass =moles\times molar\ mass\\\\\\=0.762\times 63.546\\\\=48.422\ g[/tex]
-We apply the specific heat formula to calculate the amount of heat released:
[tex]q=mC\bigtriangleup T\\\\\\=48.422\ g\times 0.385 \ J/g\textdegree C\times (81.6-52.2)\textdegree C\\\\\\=548.089 J[/tex]
Hence, the amount of heat released is 548.089 J
The heat released when 0.762 mol of copper cools from 81.6°C to 52.2°C can be calculated using the formula q = mcΔT where q is the heat transferred, m is the mass, c is the specific heat capacity and ΔT is the temperature change. The calculated heat released is approximately -548.07 Joules.
Explanation:To calculate the heat released when 0.762 mol of the copper cools from 81.6°C to 52.2°C, we need to first know the specific heat capacity of copper, which is 0.385 J/g°C.
Calculate the temperature change: ΔT = Tfinal - Tinitial = 52.2°C - 81.6°C = -29.4°C. The negative sign indicates a decrease in temperature or that heat is released. Convert the number of moles of copper to mass: mass = moles x molar mass = 0.762 mol x 63.5 g/mol = 48.4 g. Then, use the equation for heat transfer: q = mcΔT where m is the mass of the copper, c is the specific heat capacity of copper, and ΔT is the temperature change. Substituting the known values gives q = 48.4 g x 0.385 J/g°C x -29.4°C. Doing the math, q = -548.07 Joules. As q is negative, this indicates that heat is released.Learn more about Heat Transfer here:
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which system at equilibrium will shift to the right when the pressure is increased?
A)NaCl(s)-Na+(aq)+Cl-(aq)
b)c2h5OH(l) -- c2h5OH (aq)
c) NH3(g) ---NH3(aq)
d)c6h12o6(s) ---- c6h12o6(aq)
Answer: (C) NH3(g)-- NH3(aq)
Explanation:
The system at equilibrium will shift to the right when the pressure is increased is NH₃(g) = NH₃(aq) and the correct option is option C.
What is Chemical Equilibrium?Chemical equilibrium refers to the state of a system in which the concentration of the reactant and the concentration of the products do not change with time, and the system does not display any further change in properties.
It is the state of a reversible reaction where the rate of the forward reaction equals the rate of the reverse reaction. While a reaction is in equilibrium the concentration of the reactants and products are constant.
Equilibrium shifts in the direction of lesser number of moles when the temperature is increased.
Therefore, the system at equilibrium will shift to the right when the pressure is increased is NH₃(g) = NH₃(aq) and the correct option is option C.
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If 251 mL of 6.0 M H2SO4 is diluted to 500. mL, what is its new molarity?
Answer:
3.0MExplanation:
The dilution formula is:
[tex]M_1\times V_1=M_2\times V_2[/tex]
Where M₁ and M₂ are the molar concentrations and V₁ and V₂ are the volumes of the concentrated and the diluted solutions.
Substitute:
M₁ = 6.0MM₂ = unknownV₁ = 251 mLV₂ = 500. mL[tex]6.0M\times 251ml=M_2\times 500.ml[/tex]
Clear M₂ and compute:
[tex]M_2=6.0M\times 251ml/500.ml\approx3.0M[/tex]
how are biomes determined
Answer: A biome is an area of the planet that can be classified according to the plants and animals that live in it. Temperature, soil, and the amount of light and water help determine what life exists in a biome. A biome is different from an ecosystem. ... Some use broad classifications and count as few as six biomes.
Explanation: Im good in science and stuff
Answer:
they are determined by what kinds of plants and animals are able to live and survive there due to temperature, the amount of water and light there, and soil
Explanation:
A water molecule collides with a sugar molecule. What type of energy
is transferred in this interaction?
Select one:
Sound energy
Kinetic energy
Chemical energy
Heat energy
Answer:
kinetic energy.
Explanation:
an object in motion collides with another object to make that object in motion.
kinetic energy is the energy of an object being in motion.
3. What is the relationship between the kinetic energy of gas particles and the
temperature of the gas?
Answer:
The average kinetic energy of the particles in a gas is proportional to the temperature of the gas.
Explanation:
Because the mass of these particles is constant, the particles must move faster as the gas becomes warmer.
The Relationship between the kinetic energy and temperature of a gas is : Kinetic energy of a gas is directly proportional to the temperature (K∝T)
Meaning of kinetic energy, temperature and their relationshipKinetic energy is the energy contained by a particle by the reason of it motion.
temperature can be said be the degree of hottness or degree of coldness of a particle.
Because the particles of has have a negligible force when they are heated they become excited and move about randomly. so the more the heat the faster they move.
we can conclude by saying that the Kinetic energy of a gas is directly proportional to the temperature (K∝T).
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Baking Soda Acidic, alkaline, or neutral?*
O
Acidic
Alkaline
Neutral
Answer:
Baking soda, also known as sodium bicarbonate, is a base
Baking soda, or sodium bicarbonate, is an alkaline substance with a pH greater than 7, indicating its basic properties. It reacts with acids in baking to produce carbon dioxide, helping the dough to rise. The correct answer is B) Alkaline.
Sodium bicarbonate, commonly known as baking soda, is a chemical compound with the formula [tex]NaHCO_3[/tex]. It is a white solid that is crystalline but often appears as a fine powder. Baking soda is not neutral or acidic; it has alkaline properties.
When baking soda is dissolved in water, it slightly raises the pH of the solution, making it basic. The pH scale, which measures how acidic or alkaline a substance is, typically ranges from 0 (very acidic) to 14 (very alkaline), with 7 being neutral. Sodium bicarbonate usually has a pH greater than 7; therefore, it can help neutralize acids.
When used in baking, baking soda acts as a base and usually reacts with an acidic ingredient (like lemon juice or buttermilk).
This reaction produces carbon dioxide gas, which causes dough or batter to expand and "rise," giving baked goods their porous texture. The equation for its reaction with an acid is as follows: [tex]NaHCO_3(s) + H^+[/tex] → [tex]Na^+ + H_2O + CO_2[/tex]. This demonstrates baking soda’s role as a base in neutralizing acids and producing carbon dioxide and water.
A 50.00 g sample of an unknown metal is heated
to 45.00°C. It is then placed in a coffee-cup
calorimeter filled with water. The calorimeter and
the water have a combined mass of 250.0 g and
an overall specific heat of 1.035 cal/g•°C. The
initial temperature of the calorimeter is 10.00°C.
The system reaches a final temperature of
11.08°C when the metal is added.
What is the specific heat of the metal
Answer:
.1648 cal/g•°C
Explanation:
Complete and balance the following redox reaction in acidic solution As(s) -> H 2 AsO 4 (aq)+ASH 3 (s)
Answer:
12H2O + 8As = 3H2AsO4- + 5AsH3 + 3H+
Explanation:
- This is balanced in an acidic solution and should be correct.
Why are plastics called polymers? Explain the nature of a polymer.
Hurry please!
Answer:
Plastics and natural materials such as rubber or cellulose are composed of very large molecules called polymers .
Explanation:
hi
why does poop turn blue after you bleach it
Enzymes and activators in the poop might cause the bleach to decompose quickly, releasing chlorine gas. Otherwise, it would have the effect making your toilet smell like a swimming pool, which might be a worthwhile improvement.
How many different kinds of atoms do occur naturally on earth? Why do you think so?
Final answer:
Ninety-two different atoms occur naturally on Earth, and these are detailed in the Periodic Table of Elements. Atoms are distinguished by the number of protons in their nucleus, while isotopes of these elements differ by their neutron count. Evidence of atoms includes the periodic table's structure and Brownian motion.
Explanation:
There are 92 different kinds of atoms that occur naturally on Earth. These are the building blocks of all matter and are listed in the Periodic Table of the Elements. Each atom type, or element, has a unique number of protons in its nucleus, which also dictates the number of electrons that orbit the nucleus.
When considering the number of neutrons, atoms of the same element can have different numbers, leading to various isotopes. For instance, while 99% of carbon atoms on Earth have 6 neutrons, about 1% have 7 neutrons. Thus, what we see in nature is actually a mixture of isotopes, with most elements having at least one stable isotope.
Despite the ancients believing in only four types of atoms (earth, water, air, and fire), we now understand there are many more, with distinct properties such as atomic weight, size, and structure. We can't observe atoms with visible light due to their incredibly small size, which is below the wavelength of light that our eyes can detect. However, we have evidence of their existence, such as the patterns in the periodic table and the phenomenon of Brownian motion.
What is the Molar mass of Fe2(SO4)3
Answer:
399.88
Explanation:
The molar mass is just the number of total mass of each atom of each element.
2 - Fe = (55.845 x 2) = 111.69
3 - S = (32.06 x 3) = 96.18
12 - O = (15.999 x 12) = 191.988
For oxygen, it's being added 12 times because there is 4 in the compound times the 3 on the outside.
Now, add all of them and you have your answer!
The molar mass of
[tex]Fe2(SO4)3,[/tex]I) sulfate, is calculated by adding up the molar masses of its individual atoms. It has 2 atoms of iron, 3 molecules of sulfate (each containing 1 sulfur atom and 4 oxygen atoms). This adds up to approximately 400.01 g/mol.
Explanation:To calculate the molar mass of
[tex]Fe2(SO4)3[/tex]own as iron(III) sulfate, you should add up the molar masses of all the atoms in the formula. Iron ('Fe') has a molar mass of about 55.85 g/mol. Sulfur ('S') has a molar mass of about 32.07 g/mol, and oxygen ('O') has a molar mass of about 16.00 g/mol. The compound has 2 atoms of iron, 3 molecules of sulfate (each containing 1 sulfur atom and 4 oxygen atoms).
Calculating these gives:
[tex](2*55.85 g/mol) + [3*(32.07 g/mol + (4*16.00 g/mol))] = 111.7 g/mol + 3*96.07 g/mol = 400.01 g/mol[/tex]
So the molar mass of Fe2(SO4)3 is approximately 400.01 g/mol.
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Which substance would be able to pass through filter paper when added to water?
Answer:
The salt and water will pass through the filter paper while the large, undissolved pieces of sand will be trapped by the filter paper. The liquid that passes through the filter paper and is collected in the beaker is called the filtrate.
Explanation:
If you look on google it will give you the answer: Salt.
What type of intermolecular bond occurs between two water molecules?
A) dipole to dipole
B) hydrogen
C) ionic
D) polar covalent
What state of matter has the strongest intermolecular forces?
A) solid
B) none of these choices
C) liquid
D) gas
Answer:
Solid
Explanation:
As the temperature continues to drop, the matter forms a solid. Due to the solid's low kinetic energy, particles have no "time" to move around, the particles have more "time" to be attracted. Therefore, solids have the strongest intramolecular forces (because they have the strongest attraction).
If 27.9 grams of calcium carbonate reacts with excess HCl, how many moles of calcium chloride are produced
Answer:
[tex]\large \boxed{\text{0.2797 mol}}[/tex]
Explanation:
We must do the conversions:
mass of CaCO₃ ⟶ moles of CaCO₃ ⟶ moles of CaCl₂
We will need a chemical equation with masses and molar masses, so, let's gather all the information in one place.
Mᵣ: 100.09 110.98
CaCO₃ + 2HCl ⟶ CaCl₂ + CO₂ + 2HCl
m/g: 27.9
(a) Moles of CaCO₃[tex]\text{Moles of CaCO}_{3} = \text{27.9 g CaCO}_{3}\times \dfrac{\text{1 mol CaCO}_{3}}{\text{100.09 g CaCO}_{3}}= \text{0.2787 mol CaCO}_{3}[/tex]
(b) Moles of CaCl₂[tex]\text{Moles of CaCl}_{2} =\text{0.2787 mol CaCO}_{3} \times \dfrac{\text{1mol CaCl}_{2}}{\text{1 mol CaCO}_{3}} = \text{0.279 mol CaCl}_{2}[/tex][tex]\text{The reaction produces $\large \boxed{\textbf{0.279 mol}}$ of CaCl}_{2}[/tex]