Finding dead insects or mouse droppings in the kitchen is an indication of pest infestation.
Pests are living organisms that are capable of spreading diseases, causing economic damages, or generally constituting nuisance to the environment.
Pest infestation occurs when there is a high number of pests in the environment. When this occurs, their activities are felt in the environment in terms of causing a nuisance, and damaging properties or contaminating foods.
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5. To investigate electrostatic forces between molecules in water and in ethanol, a student pours identical amounts of the liquids into two identical beakers. The student then places objects of different weights in the beakers. Which characteristic is the student most likely testing?
A. melting point
B. boiling point
C. surface tension
D. vapor pressure
The student then places objects of different weights in the beakers, surface tension is the characteristic is the student most likely testing.
What is surface tension ?Surface tension is the propensity for liquid surfaces that are at rest to condense into the smallest surface area. Razor blades and insects, which have a density greater than that of water, can float on the surface of the water without even becoming partially buried because of surface tension.
A liquid surface's ability to operate like a stretched elastic membrane is known as surface tension. Small liquid drops and soap bubbles have almost spherical shapes, which are indicators of these phenomena. Some insects can stand on the surface of water due to this characteristic.
Surface tension is a crucial factor in many industrial processes, such as detergent formulation, paint optimization, improved oil recovery, medicinal compound performance, and food product stability.
Thus, option C is correct.
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For the diprotic weak acid H2A, a1=3.2×10−6 and a2=6.1×10−9 .
What is the pH of a 0.0750 M solution of H2A ?
What are the equilibrium concentrations of H2A and A2− in this solution?
In the first dissociation of H2A:
molarity H2A(aq)↔ (HA)^-(aq) + H^+(aq)
initial 0.05 m 0 m 0 m
change -x +x +x
equilibrium 0.05-x x x
we can neglect X in [H2A] as it so small compared to the 0.05
so by substitution in Ka equation:
Ka1 = [HA][H] / [H2A]
2.2x10^-6 = X^2/0.05
X = √(2.2x10^-6)*(0.05)= 1.1x10^-7
X= 3.32x10^-4 m
∴ [H2A] = 0.05 - 3.32x10^-4 = 0.0497 m
[HA] = 3.32x10^-4 m
[H] = 3.32x10^-4 m
the second dissociation of H2A: when ka2 = 8.2x10^-9
HA-(aq) ↔ A^2- (aq) + H+(aq)
at equilibrium 3.32x10^-4 y 3.32x10^-4
Ka2 = [H+][A^2-] / [HA]
8.2x10^-9 = Y(3.32x10^-4)/(3.32x10^-4)
∴y = 8.2x10^-9 m
∴[A] = 8.2x10^-9 m
PH= -㏒[H+]
= -㏒(3.32x10^-4)= 3.479
[A]=8.2x10^-9 m
[H2A] = 0.0497 ≈ 0.05 m
Which one of these is not an important structural feature found by the number of
electron rich regions
Hybridization
Bond Angles
Electronegativity
Electron Geometry
Answer:
Electronnegativity
Explanation:
There are three important structural features: Hybridization, Bond angels, and Electron Geometry.
The not so important structural feature found by the number of electron rich regions is electronegativity. Hence option c is correct.
What are structural feature?Structural feature is defined as the modeled as a directed acyclic graph (DAG), with the variable names as pathways and the variable values as nodes. The study of the construction of biological molecules is known as structural biology. Scientists study molecules in three dimensions using a range of imaging techniques to examine how they are put together, how they work, and how they interact.
Electronegativity is defined as the propensity for atoms involved in covalent bonds to draw the bonding electrons. The negatively charged electrons are drawn to the positively charged protons in the nucleus. The electronegativity or attraction will rise with the number of protons in the nucleus. Therefore, in a row of the periodic table, electronegativity rises from left to right.
Thus, the not so important structural feature found by the number of electron rich regions is electronegativity. Hence option c is correct.
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PLEASE ITS DUEE TODAY at 6:00PM!!!!!
Please draw the complete chemical structure of the tripeptide having the amino acidsequence: Asp-Leu-Ser
Answer:
I got you... 2 amino acids are linked to each other by a peptide linkage. A peptide linkage is formed when carboxyl group of one amino acid combine with the amine group of the other and during this process, a water molecule is removed.
The given tripeptide will have 2 peptide bonds. To draw the structure of given tripeptide, we will arrange them in the given order and then we will remove 2 water molecules to form 2 peptide bonds.
Explanation:
Hope this helps:)
a
A molecule that experiences London dispersion forces is
likely to have a • boiling point than a molecule
experiencing a dipole-dipole interaction.
pls
Answer:
it should be the second one since London dispersion causes interaction between molecules.
hope I helped.
Generally non ionic species with no polarity forms the London -dispersion bonds. London dispersion is weaker than the dipole-dipole interaction and hence it have less boiling point.
What is boiling point?Boiling point of a substance is the temperature at which the substance changes from liquid state to gaseous state or vapor where, the two states are in equilibrium.
Boiling of a substance depends on the molecular weight, bond type,temperature, pressure as well as purity of the substance.
London dispersion force is formed between two non-polar atoms. These atoms when come closer they attains a temporary polar nature and gets bonded.
Dipole-dipole bond is formed between two atoms of permanent dipole moment and they are polar compounds. Thus dipole-dipole interaction is stronger than London dispersion interaction. A strong bond needs more energy to boil.
Hence, molecules with Dipole-Dipole bond is having higher boiling point.
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What kind of fault movement will create a tsunami?
Answer:
I THINK IT'S BECAUSE THE EARTH UNDER THE SEA SHIFTS AND THE VIBRATION OF THE WATER GETS BIGGER UNTIL IT BECOMES A TSUNAMI. BRAINLIST ???
*1. The internal energy with a system associated with the motion of particles and that can be added to a substance is called_____.
A. Thermal energy
B. Electrostatic forces
C. Temperature
D. Kinetic energy
•
•
•
*2. Which statement describes the effect of adding more energy to a system, assuming a phase change does not occur?
A. The particles within the system will have greater motion, and the temperature will decrease.
B. The particles within the system will have greater motion, and the temperature will increase.
C. The particles within the system will have less motion, and the temperature will increase.
D. The particles within the system will have less motion, and the temperature will decrease.
•
•
•
*3. Which statement correctly describes how attractions that hold particles break?
A. Attractions due to electrostatic forces. When particles have low enough energy, these forces can no longer keep particles together.
B. Attractions due to gravitational forces. When particles have low enough energy, these forces can no longer keep particles together.
C. Attractions due to gravitational forces. When particles move fast enough, these forces can no longer keep particles together.
D. Attractions due to electrostatic forces. When particles move fast enough, these forces can no longer keep particles together.
•
•
•
*4. Which statement explains why a rubber band analogy is not a perfect comparison for bonds in a substance when considering phase changes?
A. For a phase change from liquid to gas, the bonds break completely and particles can move independently of each other.
B. For a phase change from liquid to gas, the bonds do not break completely and the particles can still slide past each other.
C. For a phase change from solid to liquid, the bonds break completely and particles can move independently of each other.
D. For a phase change from solid to liquid, the bonds do not break completely in the particles can still slide past each other.
•
•
•
*5. The boiling point of benzene is 80°C. Which pair of samples will have the same average kinetic energy as benzene molecules?
A. Two samples of liquid benzene, one at 70°C in the other at 80°C.
B. A sample of liquid benzene at 70°C and a sample of gaseous benzene at 90°C.
C. Two samples of gaseous benzene, one at 80°C in the other at 90°C.
D. A sample of liquid benzene at 80°C and a sample of gaseous benzene at 80°C.
Answer:
1. thermal energy
2. the particles within the system will have greater motion, and the temp will increase.
3. attractions occur due to electrostatic forces. when particles move fast enough, these forces can no longer keep particles together.
4. for a phase change from a solid to liquid, the bonds do not break completely and particles call still slide past each other.
5. a sample of liquid benzene at 80°C and a sample of gaseous benzene at 80°C
Explanation:
hope this helps
Temperature is a measure of the average kinetic energy of molecules.
The particles of a substance are in constant random motion. As more thermal energy is added to the particles, the motion of the particles increases. If more energy is added to a system during phase change, the particles within the system will have greater motion, and the temperature will increase.
Attractions between particles is greater when the kinetic energy of molecules decreases. Therefore, a statement that correctly describes how attractions that hold particles break is; "attractions due to electrostatic forces. When particles move fast enough, these forces can no longer keep particles together."
The rubber analogy is commonly used to describe covalent bonds where stretching of bonds occur. This analogy is not apt in describing phase changes because for a phase change from a solid to liquid, the bonds do not break completely and particles call still slide past each other.
The average kinetic energy of molecules depend on temperature hence a sample of liquid benzene at 80°C and a sample of gaseous benzene at 80°C will have the same average kinetic energy.
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please help me! giving brainliest!!
Answer:
It is a covalent bond because both carbon and oxygen are nonmetals. The formula will be CO² because the electrons between the atoms are being shared equally.
Answer:
Option C
Explanation:
CO₂ is a covalent bond because we know that both elements are nonmetals. The carbon atoms shares 2 electrons with each oxygen atom and each oxygen atom shares two electrons with the carbon atom. CO₂ forms a nonpolar covalent bond, meaning that the electrons are shared equally.
what are massless particles
Answer:
particals that have no mass
Explanation:
key word maseless
please help me
Select the correct answer.
Who founded the specialized field of anatomy?
A. Herophilus
B. Aristotle
C. Claudius Galen
D. William Harvey
Answer:
the correct answer is A. please mark me brainlist
Explanation:
Answer:
geon, Andreas Vesalius. Vesalius describes what he observes during the public dissection of human corpses. By dissecting human bodies, preparing muscles, tendons, and nerves down to the smallest detail, Vesalius is able to prove more than 200 errors in Galen’s anatomical works.
Explanation:
With his comprehensive scientific studies of human bodies, the young professor of medicine not only revolutionizes anatomy, but consequently, the whole science of medicine.
I know I never completely answered your question, I just wanted to explain it was E. None of the above.
If a barometer were built using water (d=1.0 g/cm3) instead of mercury (d=13.6 g/cm3), would the column of water be higher than, lower than, or the same as the column of mercury at 1.00 atm? If the level is different, by what factor? Explain.
Explanation:
A more dense liquid stays lower while a less dense liquid stays higher. since water is 13.6 times less dense than mercury, the column for a barometer using water would have to be 13.6 times taller.
A reaction mixture initially contains 0.236 mol FeS and 0.670 mol HCl. Once the reaction has reached completion, what amount (in moles) of the excess reactant is left
Answer:
= 0.198 mole H₂S in excess
Explanation:
A quick way to determine limiting reactant is to convert reactant values given to moles and divide by respective coefficient. The smaller value is the limiting reactant other reactants will be in excess. However, when working problem, use mole values given to solve, not results of division.
FeS + 2HCl => FeCl₂ + H₂S
0.236mole/1 0.670mole/2
= 0.236 = 0.335
limiting reactant is FeS; HCl will be in excess.
Problem solution
0.236mole FeS used + 2(0.236 mole HCl used)
=> 0.236 mole FeCl₂ + 0.236 mole H₂S + (0.670 - 0.472) mole HCl in excess or, 0.198 mole H₂S in excess.
Hope this helps. :-)
Write and balance the equation for the complete combustion of heptane, C7H16. Phase symbols and energy changes are optional.
The balanced equation for the complete combustion of heptane, [tex]C_{7}H_{16}[/tex] is given as,
[tex]C_{7}H16(g) + 11O_{2} (g)[/tex] → [tex]7CO_{2}(g) + 8H_{2}O(g)[/tex] + heat/light
What is combustion reaction?It is exothermic redox chemical reaction.The reaction between fuel and oxidant to produce oxidized product is called combustion reaction.The oxidant are usually atmospheric oxygen.The oxidized product is carbon dioxide gas and water.What is balanced chemical equation?The chemical equation in which number of atom each elements is equal in reactant and product of the reaction is called balanced chemical equation.
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Calculate the pH when the following quantities of 0.100 M NaOH solution have been added to 50.0 mL of 0.100 M HCl solution
Answer:
see explanation
Explanation:
Given 0.100M NaOH + 50ml 0.100M HCl
If 50ml of 0.100M NaOH is added to 50ml 0.100M HCl => pH = 7
if less than 50ml of 0.100M NaOH => pH < 7
if more than 50ml of 0.100M NaOH => pH > 7.
Example:
50ml(0.100M NaOH) + 50ml(0.100MHCl) =>
0.500mole NaCl + 0.500mole H₂O
In this mix, both NaOH and HCl are converted to NaCl and H₂O and NaOH or HCl are no longer present giving a neutral solution. Since neither Na⁺ nor Cl⁻ undergo hydrolysis, the pH is dependent upon H₂O ⇄ H⁺ + OH⁻ and [H⁺] = [OH⁻] = 10⁻⁷M => pH = -log[H⁺] = -log(10⁻⁷) = -(-7) = 7
If less than 50ml of 0.100M NaOH is added, the mix will have an excess of HCl and the pH will be acidic; i.e., less than 7.
If more than 50ml of 0.100M NaOH is added, the mix will have an excess of NaOH and the pH will be alkaline (basic); i.e., greater than 7.
Which unit is 10,000 times LARGER than the MICRO unit?
Answer:
Micro means 0.000001. So 10,000 times larger than that is the Centi unit, which is 0.01
Identify the major ionic species present in an aqueous solution of C6H12O6 (glucose).
A. 6 C-
, 12 H+
, 6 O–
B. 6 C+
, 12 H+
, 6 O2–
C. 6 CH2+, 6 O2–
D. C6
+
, 12 H+
, 6 O2–
E. no ions are present
Glucose is a molecular substance therefore, there are no ionic species in glucose.
Ionic substances dissolve in water to yield ions. Molecular substances do not produce ions in solution. The conductivity of ionic solutions owes to the presence of ions in solutions. Molecular solutions do not conduct electricity due to the absence of ions.
Glucose is a molecular substance hence they are are no ions present hence glucose does not conduct electricity.
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What is the molality of sodium chloride in solution that is 13.0% by mass sodium chloride and that
the solution has a density of 1.10 g/mL?
Answer:
2.4 M
Explanation:
1. Suppose you have 100 mL solution:
Use density to find grams of solution:
100 mL solution x (1.10 g / 1 mL) = 110 g solution
2. FInd the amount of sodium chloride pure:
110 g solution x(13 g NaCl / 100 g solution) = 14.3 g NaCl
3. Change grams to mol:
14.3 g NaCl x ( 1 mol NaCl/ 58.44 g NaCl) = 0.24 mol NaCl
4. Molarity:
M = mol NaCl / L solution
M = 0.24 mol NaCl / 0.1 L = 2.4 M
name 2 elements that are liquid at room temperature and describe their colour
Answer:
Bromine
Mercury
Bromine (symbol Br and atomic number 35) is a reddish-brown liquid, with a melting point of 265.9 K. Mercury (symbol Hg and atomic number 80) is a toxic shiny silvery metal, with a melting point of 234.32 K.
Help please :) with this
Answer:
The answer is 3
Explanation:
Hope this helps and have a wonderful day.
Which of the following frequencies of light has the lowest energy?
Answer:
Radio waves have photons with the lowest energies. Microwaves have a little more energy than radio waves. Infrared has still more, followed by visible, ultraviolet, X-rays and gamma rays.what is the best way to learn and understand high school chemstry?
Answer:
Firstly, try to Go through your chapter and pay attention to main keywords.
secondly try to watch 'Uube' videos related to specific topic instead of chapter and pay attention to it closely and watch it with a keen interest.
Discuss topics that you find harder with your friends or peer group members, Because you learn faster when you study with the people of your age.
Answer:
i think the best way to learn chemistry is study over things that involve it
Explanation:
Explain why most cells must be microscopic (so small they must be viewed with a microscope) in order to maintain life properly.
Answer:
if the cell grows beyond a certain limit, not enough material will be able to cross the membrane fast enough to sustain the increased cellular volume
Answer: In most cells, this passage of all materials in and out of the cell must occur through the plasma membrane
Explanation:
Respiration describes the process that living cells use to release energy by combining sugar and oxygen. The primary chemical changes that happen during respiration are shown in the equation below.
C6H12O6 + 6O2 ---> 6CO2 + 6H2O + energy
Which statement correctly compares the reactants and products of the equation?
A.
The mass of the reactants is less than the mass of the products.
B.
The mass of the reactants is greater than the mass of the products.
C.
The mass of the reactants is the same as the mass of the products.
D.
The number of reactant molecules is greater than the number of products.
Answer:
C the mass of the reactant molecules is the same as the mass of the product
which phase has the highest entropy?
a. gas
b. liquid
c. solid
d. aqueous
Answer:
Gas>Liquid>Solid
Explanation:
Entropy by definition is the degree of randomness in a system. If we look at the three states of matter: Solid, Liquid and Gas, we can see that the gas particles move freely and therefore, the degree of randomness is the highest.
As the reaction goes through phases, the phase that has the highest entropy is the gas state. This is further explained below. Option A is correct.
What is entropy?A thermodynamic number that represents the inability of a system's thermal energy to be converted into mechanical work, and is commonly understood as the system's degree of disorder.
In conclusion, we have that as the reaction goes through phases, the gaseous state has the highest entropy.
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The partial pressure of CO2 gas in a bottle of carbonated water is 4.60 atm at 25 ºC. How much CO2 gas (in g) will be released from 1.1 L of the carbonated water when the partial pressure of CO2 is lowered to 1.28 atm? At 25 ºC, the Henry’s law constant for CO2 dissolved in water is 1.65 x 103 atm, and the density of water is 1.0 g/cm3.
If the partial pressure of CO₂ in a bottle of carbonated water decreases from 4.60 atm to 1.28 atm, the mass of CO₂ released is 0.265 g.
The partial pressure of CO₂ gas in a bottle of carbonated water is 4.60 atm at 25 ºC. We can calculate the concentration of CO₂ using Henry's law.
[tex]C = k \times P = \frac{1.65 \times 10^{-3} M }{atm} \times 4.60 atm = 7.59 \times 10^{-3} M[/tex]
We can calculate the mass of CO₂ in 1.1 L considering its molar mass is 44.01 g/mol.
[tex]\frac{7.59 \times 10^{-3} mol}{L} \times 1.1 L \times \frac{44.01 g}{mol} = 0.367 g[/tex]
Now, we will repeat the same procedure for a partial pressure of 1.28 atm.
[tex]C = k \times P = \frac{1.65 \times 10^{-3} M }{atm} \times 1.28 atm = 2.11 \times 10^{-3} M[/tex]
[tex]\frac{2.11 \times 10^{-3} mol}{L} \times 1.1 L \times \frac{44.01 g}{mol} = 0.102 g[/tex]
The mass of CO₂ released will be equal to the difference in the masses at the different pressures.
[tex]m = 0.367 g - 0.102 g = 0.265 g[/tex]
If the partial pressure of CO₂ in a bottle of carbonated water decreases from 4.60 atm to 1.28 atm, the mass of CO₂ released is 0.265 g.
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The partial pressure of CO₂ gas in a bottle of carbonated water is 4.60 atm at 25 ºC. How much CO₂ gas (in g) will be released from 1.1 L of the carbonated water when the partial pressure of CO2 is lowered to 1.28 atm? At 25 ºC, the Henry’s law constant for CO₂ dissolved in water is 1.65 x 10⁻³ M/atm, and the density of water is 1.0 g/cm³.
How does using more water in a beaker affect the solubility in an experiment?
What does percent composition tell you about a molecule?
O A. It tells you how the elements are arranged in the molecule.
B. It tells you the ratio of elements in the molecular formula.
C. It gives you the total number of atoms in the molecule.
D. It tells you how much of a molecule is made up of each element.
SUBMIT
Answer:
B
Explanation:
percentage composition helps to determine the percentage of each element in a compound
A student wants to show the transfer of heat energy without matter which investigation design would best help the student
A) an investigation of radiation through a current in a fluid
B) an investigation of radiation through electromagnetic waves
C) an investigation of conduction through collisions between particles in space
D) an investigation of conduction through the movement of particles through a solid
Answer:
C
Explanation:
According to the concept of thermal energy, transfer of heat energy can be depicted by investigation of conduction through collisions between particles in space.
What is thermal energy?Thermal energy is defined as a type of energy which is contained within a system which is responsible for temperature rise.Heat is a type of thermal energy.It is concerned with the first law of thermodynamics.
Thermal energy arises from friction and drag.It includes the internal energy or enthalpy of a body of matter and radiation.It is related to internal energy and heat .It arises when a substance whose molecules or atoms are vibrating faster.
These vibrating molecules and atoms collide and as a result of which heat is generated in a substance , more the collision of particles , higher is the thermal energy.
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Help with this please
Answer:
12
Explanation:
There are 4 sulfur atoms in SO4
4×3=12
This means that it turns into 3×(SO4)
=3SO4
Calculate the mass of butane needed to produce 57.3 g of carbon dioxide.
Answer:
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