Answer:
Explanation:
1. diffusion is a physical process when there is random motion of molecules by which there is a net flow of matter from a region of high concentration to a region of low concentration.
2. Osmosis is the diffusion of water where molecules of water move passively (without energy) from high concentration to low concentration. eg: the way water rushes into a sponge.
3. Active transport moves particles from low to higher concentration. The difference between diffusion and active transport is diffusion does not require energy (eg: oxygen moving from the airways to the lungs - there is very little oxygen in the lungs but lots in the air). whereas active transport does require energy (eg: when plants take up nutrients from the soil. The soil does not have a large concentration of nutrients, but the plant does)
A leaky faucet can waste 3,000 gallons of water per year. Which of the following is correct to convert the water wasted to liters/month? [1 gallon = 3.8 liters]
a
Divide 3,000 by 3.8
b
Multiply 3,000 by 12
c
Multiply 3,000 by 3.8 and divide the result obtained by 12
d
Divide 3,000 by 3.8 and multiply the result obtained by 12
Answer:
c
Multiply 3,000 by 3.8 and divide the result obtained by 12
Alchemy is the process of trying to turn non-gold metals into gold. It was practiced hundreds of years ago by scientists who believed that with the right amounts of heat or chemical reactions, they could make gold. After years of experiments and observations, gold was never produced. Which best describes the practice of alchemy
Answer:
Alchemy is a practice of making gold from other metals.
Explanation:
Alchemy is a method which is practiced by the ancient scientists of Europe, Africa and Asia trying to produced gold from other metals. This method was failed to produced gold from metals and all scientist suggested that metals can not be converted into gold. Greeks were the people who presented the theory of alchemy in the first few centuries of CE.
Answer:
the answer is Alchemy was scientific because it included observations and experiments
Explanation:
i took the test
Which types of particles are found in the nucleus of the atom?
Answer:
Hope it helps you dude :)
The rate constant for a second-order reaction is 0.54 M-1s-1. What is the half-life of this reaction if the initial concentration is 0.39 M
Answer:
4.748 seconds
Explanation:
second-order is one in which the rate is proportional to the square of the concentration of one reactant. This can be expressed below;
2A----->P
Where
A is the reactant.
P is the product.
The rate can be expressed as
Rate= k[A]^2
Half-life reffers to time required to reduce the concentration of reactant to half of its initial value.
The half life of reaction can be calculated using below formula
Half-life =. 1/(K*I)
Where,
K = Rate constant = 0.54 1/ms
I = Initial concentration = 0.39 m
If we substitute these values we have
Half-life t(1/2) =1/(0.54×0.39)
=4.748 seconds
Therefore, the half life is 4.748 seconds
What entropy change is associated with the reversible phase change from 1.0kg of ice to water at 0 ° C?
Answer:
1200 J/K
Explanation:
The formula for the entropy associated with a reversible phase change is
[tex]\Delta S= \dfrac{q_{\text{rev}}}{T}[/tex]
1. Calculate q
For a reversible phase change like melting,
[tex]q_{\text{rev}} = m\Delta_{\text{fus}}H = \text{1000 g} \times \dfrac{\text{334 J}}{\text{1 g}} = \text{334 000 J}[/tex]
2. Calculate ΔS
[tex]\Delta S = \dfrac{q_{\text{rev}}}{T} =\dfrac{\text{334 000 J}}{\text{273.15 K}} = \textbf{1200 J/K}[/tex]
Which reaction is exothermic? CH4 + 2O2 Right arrow. CO2 + 2H2O + 891 kJ NH4NO3 + H2O + 25 kJ Right arrow. NH4+(aq) + NO3-(aq) 2H2O + 286 kJ Right arrow. 2H2 + O2 N2 + O2 + 181 kJ Right arrow. 2NO
Answer:
ch4 + 2o2 gives co2+2h2o +891kj
Explanation:
becoz 891kj heat energy is given out
exothermic process means heat energy is given out/ released
Among the given reactions the exothermic reaction is option a. The reaction between methane and oxygen giving out carbon dioxide and water with 891 KJ of heat energy.
What is exothermic reaction?An exothermic reaction is the reaction in which heat is evolved from the reaction system to the surroundings. The reaction container will be too hot to touch.
The enthalpy change for an exothermic reaction is negative. Whereas that for an endothermic reaction is positive where, heat is absorbed into the reaction system.
For the given reactions, all other reactions except option a are intaking some heat energy that's why written in the left side of arrow which are endothermic. Option a is the combustion of methane gas and it is exothermic.
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Hurricane Donna was one of the most severe hurricanes on record. What empirical evidence could scientists analyze and evaluate to support the statement?
Answer:
The comparison of the damages generated by Hurricane Donna with respect to others. The empirical information that can support this may be the number of homes affected or the cost of repairs after the hurricane has passed until it stops.
Explanation:
Empirical knowledge is the knowledge that it generates from experience and observation, perception tells us how something works and its natural characteristics.
If a scientist assures that it was the most severe hurricane, it is because the scientist is comparing the disasters generated by Hurricane Donna with other ones.
Answer:
I'm not quite sure.....
Explanation:
Which of the following best describes this sentence?
There were 20 flamingos at the zoo.
Group of answer choices
Qualitative observation
Quantitative observation
Qualitative inference
Quantitative inference
Answer:
i think quantitative observation
Question 5
Above is the grades for 17 students in Chemistry class. What percent received a B+? Make sure you round your answer
to two decimal places.
Answer:
There are 17.64% students received B+ grades.
Explanation:
It is given that,
Total number of students in chemistry class is 17
We need to find the percentage received by B+.
Number of students having B+ grades are 3 (from graph)
Required percentage = [tex]P=\dfrac{3}{17}\times 100=17.64\%[/tex]
So, there are 17.64% students received B+ grades.
Which of these discoveries contradict components of Dalton’s atomic theory? Check all of the boxes that apply.
Explanation:
ATOMIC THEORY
Lesson 1 - Page 5
J.J. Thomson
In 1897, English physicist J. J. Thomson (1856–1940) disproved Dalton’s idea that atoms are indivisible. When elements were excited by an electrical current, atoms break down into two parts. One of those parts is a negative tiny particle, which Thomson called a corpuscle in 1881. The term electron was introduced in 1891 by G. Johnstone Stoney (1826-1911) as a way to describe a “natural unit of electricity.” Thomson envisioned these negative charges embedded into positive charges, like an English plum pudding. The plums were the electrons and the pudding was the positive matter.
Thomson's idea of an atom did not survive very long. English physicist Ernest Rutherford (1871–1937) studied the effects of bombarding thin gold foil with alpha particles. Alpha particles are helium atoms that have lost their electrons and are positive. Rutherford’s model had a nucleus, which occupied a very small area toward the middle, and was positive. He used the term proton for the positive particles. However, his electrons were moving on the outside of the nucleus in no definable manner in his model.
A is Dalton's Model; B is Thomson;
and C is Ruthford's model of an atom
Do heavy metals like lead and arsenic cause damage to human DNA
Answer:
Yes
Explanation:
Some environmental factors- chemical, physical (UV), and biological (poisonous plants)- have the capability to damage DNA. This can lead to mutation, cell death, and several ailments.
Chemicals such as pesticides and heavy metals can be found in the environment (air, water) or in some consumer products.
The presence of Lead and a reactive oxygen species can result in DNA damage. Arsenic is classified as a carcinogen (cancer-causing substance).
More details are found in scientific articles online, but here's a helpful snippet- "heavy metal exposure can contribute to genetic damage by inducing double strand breaks (DSBs) as well as inhibiting critical proteins from different DNA repair pathways"
Lead and arsenic are heavy metals that are considered carcinogens. These metals cause alteration and damage to the genetic material and protein synthesis.
What are carcinogens?Carcinogens are said to be a substance that can lead to cancer in an organism and are produced naturally from viruses and ultraviolet rays or mna made by cigarette smoking and chemicals.
Their high exposure causes the breaking of the double strand of the DNA molecule in the cells that inhibits and prevents protein formation leading to interference with the DNA repair pathways.
Cadmium, lead, arsenic, etc., are heavy metals that are released by human activities and alter the genetic mechanism and composition leading to mutation and disorders like skin cancers, lung cancer, etc.
Therefore, lead and arsenic is carcinogens that damage DNA.
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A scientist wrote a report that communicates the steps he performed in an investigation, the data he gathered, and his conclusions. A second scientist used the report to carry out the same investigation. However, her results were very different. Are the results of the investigation described below valid? If not, what should the scientists do next? Explain your reasoning.
Answer:
yes, this is an acceptable practice in research.
Explanation:
Note that, having a different result in one's research does not imply it is automatically invalid. However, because there may have been some errors or limitations in the previous work by the male researcher, it is possible that the later results are more accurate, even though she used the same procedures. She may have been more careful when calculating her results.
Answer:
Since the results did not match, she should repeat the investigation again. If the data still cannot be replicated, then the results are not valid. In that case, the next step is to restart the process of inquiry from the beginning. An improved design might produce valid, repeatable results.
Explanation:
Can someone pls explain this to be step by step:
The density of a substance is 1.03g/cm? What would be the density in mg/mm'?
Answer:
Explanation:
You can do this by doing dimensional analysis.
The first step is to change grams to mg
1000 mg = 1 gram
So the fraction will look like this
1.03 g * 1000 mg/ 1 gram = 1030 mg (the grams cancel out)
Now move onto the volume. The volume is actually 1 cm^3. This becomes 1 cm^3 / 1000 mm^3
So the answer becomes
1030 mg / cm^3 * ( 1 cm^3/1000 mm^3) The cm^3 cancel out
1030 mg / 1000 mm^3
1.030 mg/ mm^3
What is the light transmission of chlorine?
Explanation:
The Absorption of Light by Chlorine, Bromine and their Gaseous Mixtures
Click the link here to open the atom-building interactive, and click the atom square. Use the interactive to
answer the following questions. Note: Keep all atoms neutral (net charge = 0) for this exercise. Be sure
to select the "plus" sign to expand the element, mass number, and net charge windows.
Make a He atom with a mass of 4. How many protons did you put in the nucleus?
Make a Li atom with a mass number of 7. How many electrons did you place in the outermost orbital
(ring)?
Make a N atom with a mass number of 14. How many neutrons are in the nucleus?
Make a B atom with a mass number of 11. How many electrons did you put in the second orbital (ring)?
Answer:
2 protons, 1 electron, 7 neutrons, and 3 electrons
Explanation:
Make a He atom with a mass of 4. How many protons did you put in the nucleus?
2 protons
Make a Li atom with a mass number of 7. How many electrons did you place in the outermost orbital (ring)?
1 electron
Make a N atom with a mass number of 14. How many neutrons are in the nucleus?
7 neutrons
Make a B atom with a mass number of 11. How many electrons did you put in the second orbital (ring)?
3 electrons
Answer:
2 protons, 1 electron, 7 neutrons, and 3 electrons
Explanation:
Can anyone solve this please. I need this fastly
Answer:
Average atomic mass = 63.3896
Explanation:
Step 1: Find how much Cu-65 we have
1 - Amount of Cu-63 = Amount of Cu-65
1 - 0.6915 = Amount of Cu-65
Amount of Cu-65 = 0.305
Step 2: Find the average atomic mass of Cu
(0.6915 x 63) + (0.305 x 65) = Average atomic mass
(43.5645) + (19.825) = Average atomic mass
63.3895 = Average atomic mass
Therefore the average atomic mass of Cu is 63.3895 atomic mass units
Zinc carbonate dissolves in water to the extent of 1.12 x 10-4 g/L at 25 C. Calculate the solubility product Ksp for ZnCO3 at 25 C.
Answer:
Ksp= 7.98 × 10^-13
Explanation:
According to the question, we are to calculate the solubility constant (Ksp) of Zinc carbonate (ZnCO3) in a dissolved solution.
The equilibrium of the reaction is:
ZnCO3 (aq) ⇌ Zn2+ (aq) + CO32- (aq)
According to this; 1 mole of Zinc carbonate (ZnCO3) dissolves to give 1 mole of Zinc ion (Zn2+) and 1 mole of carbonate ion (CO32-).
This illustrates that:
(Zn2+) = 1.12 x 10-4 g/L
(CO32-) = 1.12 x 10-4 g/L
However, 1.12 x 10-4 g/L is the solubility in mass concentration of ZnCO3, we need to convert it to molar concentration in mol/L by dividing by the relative molar mass of ZnCO3.
To calculate the molar mass of ZnCO3, we say:
Zn (65.4) + C (12) + 03 (16×3)
= 65.4+12+48
= 125.4g/mol.
Hence, molar concentration= 1.12 x 10-4 g/L / 125.4 g/mol
= 8.93 × 10^-7 mol/L.
Therefore;
Zn2+) = 8.93 x 10-7 mol/L
(CO32-) = 8.93 x 10-7 mol/L
Ksp = [Zn2+] [CO32-]
Ksp = (8.93 x 10-7) × (8.93 x 10-7)
Ksp = 7.98 × 10^-13
Question 7 (5 points)
(01.03 LC)
The atoms and molecules in a liquid are in constant motion. As temperature decreases, what is true of the particles in the liquid? (5 points)
a.) The distance between the particles increases.
b.) The attraction between the particles decreases.
c.) The rate of particle movement decreases.
d.) The potential energy of the particles decreases.
Answ Es la B .
Explanation
By raising the temperature of a liquid, it turns into a gas, therefore its particles will have more movement and its kinetic energy will increase. the more you raise the temperature, the more space they will have between the molecules.
What is the mass, in grams, of 1.33 mol of water, H2O? Express the mass in grams to three significant figures.
Explanation:
First find the mass of 1 mole of water (Molecular mass)
[tex] H_{2} O = 2H + O [/tex]
[tex]
= 2(1) + 32 [/tex]
[tex]
= 34 \: grams
[/tex]
Hence 1 mole of water is 34 g
Compare
1 mole = 34 g
1.33 mole = x g
[tex] \frac{x}{34} = \frac{1.33}{1} [/tex]
[tex]
x = 1.33 \times 34 [/tex]
[tex]
\color{blue}{\boxed{x = 45.2}} \: \: \: \: to \: 3 \: s.f.
[/tex]
Therefore 1.33 moles of water is 45.2 grams
The mass of the substances can be given by the molar mass and the moles of the substances. The mass of 1.33 mole of water is expressed in grams as, 23.94 grams.
What is mass?The mass has been defined as the product of the moles of the substance and the molar mass in grams per mole. The mass is given in grams and has a formula,
Moles = mass ÷ molar mass
Mass = molar mass × moles
Given,
Moles = 1.33 moles
Molar mass of water (H₂O) is calculated as = 2 (1) + 16= 18 grams per mole
Using the formula of mole, mass is calculated as:
Mass = molar mass × moles
mass = 1.33 × 18
= 23.94 grams
The mass of the substance can be calculated if the value of the molar mass and the moles of the substance has been known. The molar mass of the substance can be calculated by adding the mass of the individual masses of the element in a molecule.
Therefore, 1.33 mol of water contains 23.94 grams.
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is 0.0410 M−1 s −1 . We start with 0.105 mol C2F4 in a 4.00-liter container, with no C4F8 initially present. What will be the concentration of C2F4 after 3.00 hours ? Answer in units of M.
Answer:
After three hours, concentration of C₂F₄ is 0.00208M
Explanation:
The rate constant of the reaction:
2 C2F4 → C4F8 is 0.0410M⁻¹s⁻¹
As the units are M⁻¹s⁻¹, this reaction is of second order. The integrated law of a second-order reaction is:
[tex]\frac{1}{[A]} =\frac{1}{[A]_0} +Kt[/tex]
Where [A] and [A]₀ represents initial and final concentrations of the reactant (C₂F₄), K is rate constant (0.0410M⁻¹s⁻¹) and t is time of the reaction (In seconds).
3.00 hours are in seconds:
3 hours ₓ (3600 seconds / 1 hour) = 10800 seconds
Initial concentration of C2F4 is:
0.105mol / 4.00L = 0.02625M
Replacing in the integrated law:
[tex]\frac{1}{[A]_0}= \frac{1}{0.02625} +0.0410M^{-1}s^{-1}*10800s\\\frac{1}{[A]_0}=480.9M^{-1}[/tex]
[A] = 0.00208M
After three hours, concentration of C₂F₄ is 0.00208M. What is the kinetic energy of a jogger with a mass of 65.0 kg traveling at a speed of 2.5 m/s?
Answer:
Kinetic energy=1/2mv^2.
1/2×65×2.5^2.
1/2×6.5×6.25.
1/2×40.625.
=20.3125Joules.
The branch of science which deals with the chemicals bond is called chemistry.
The correct answer is 20.3125J
The energy formed by the motion of particles is called kinetic energy. The formula is half of the product of the mass and velocity.
[tex]Kinetic\ energy=\frac{1}{2}mv^2.[/tex]
After putting the value:-
[tex]\frac{1}{2}*65*2.5^2.[/tex]
After solving the equation, the kinetic energy is 20.3125Joules.
Hence, the correct answer is 20.3125Joules.
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Convert each of the following lengths to the units requested.
A. 17.3 m to kilometers.
B. 2.56 m to kilometers
C. 567 dm to meters
D. 5.13 m to millimeters
Answer:
A=0.173 Km
B=0.00256 km
C=56.7 m
D=5130 mm
Explanation:
first we need to know that
[tex]1km=1000m\\\\1dm=0.1m\\\\1000mm=1m[/tex]
so we can form the following
[tex]\frac{1km}{1000m}=1\\\\\frac{0.1m}{1dm} \\\\\frac{1000mm}{1m}[/tex]
so in A
[tex]17.3m\\\\=17.3m*1\\\\=17.3m(\frac{1km}{1000m} )\\\\=0.0173km[/tex]
in B
[tex]2.56m\\\\=2.56m*1\\\\=2.56m(\frac{1km}{1000m} )\\\\=0.00256km[/tex]
in C
[tex]567dm\\\\=567dm*1\\\\=567dm(\frac{0.1m}{1dm} )\\\\=56.7m[/tex]
in D
[tex]5.13m\\\\=5.13m*1\\\\=5.13m(\frac{1000mm}{1m} )\\\\=5130mm[/tex]
Air has a mass of 1.2g and a volume of 4,555ml. What is the density
Answer:
Hey there!
Density=Mass/Volume
Density=1.2/4555
Density=2.63e-4g/cm^3
Let me know if this helps :)
Which of the following pieces of lab equipment is used to protect eyes
Cite as principais características das tentativas de organização da Tabela periódica-Tríades de Dobereiner, o Parafuso Telúrico de Chancourtois e a Lei das Oitavas de Newlands.
Answer:
Todos os três cientistas classificaram os elementos de acordo com o peso atômico.
Explicação:
As características da Tabela Periódica da Tríade Dobereiner são as seguintes:
1. é uma das classificações mais antigas de elementos.
2. nesta classificação, o peso atômico de um átomo é igual à média dos outros dois pesos atômicos.
3. é baseado no peso atômico.
Características do parafuso telúrico de Chancourtois
1. É a primeira classificação baseada no peso atômico.
2. foi a primeira representação gráfica dos elementos da tabela periódica.
Características da Lei das Oitavas de Newlands
1. também organizou os elementos de acordo com o peso atômico.
2. Em uma linha há apenas sete elementos e o oitavo vem abaixo do primeiro elemento devido às mesmas propriedades físicas e químicas.
What units should be used when describing the density of oil?
Answer:
Generally, density is measured using he SI unit for measurement of density which is kg/m³ or the cgs units used to describe the density of a substance which is g/cm³
However, due to its nature (being composed of varying amount proportions of different compounds mixed together resulting in a variation of the density of naturally produced crude oil) of having different densities whereby the lighter oils are more easily processed than the heavier variety of oils, oil density is related to the quality of the oil and it is usually measures in API gravity as follows;
°API = (141.5/S.G.) - 131.5
Where;
API = American Petroleum Institute
S. G. = Specific gravity
As such the API gravity of fresh water with a S. G. of 1.0 has is 10 degrees
Explanation:
Which bond is intermediate in terms of strength? why is it weaker than the strongest? ap bio?
Answer:
Ionic bond is the intermediate in strength.
Explanation:
Ionic bond is weaker than covalent bond and stronger than hydrogen bond in strength because in ionic bond, the atoms attract each other due to opposite in charge. Ionic bond is a type of bond in which one atom losses electron completely and become cation (positive charge) while the other atom receive the electron and become anion (negative charge). so they attract each other due to opposite charges.
If anyone is good at chemistry do you mind helping? (●'◡'●)
• Before the balloon was placed inside the hot water, the pressure was the same inside and outside the balloon. The hot water raised the kinetic energy of the air molecules inside the balloon, expanding the balloon, through thermal expansion.
• (1) the pressure of air inside the balloon increased, (2) the volume of the inside of the balloon increased as well, and (3) the temperature of the balloon increased. Note that pressure and volume are inversely proportional, and pressure and temperature are directly proportional. Therefore as the temperature increases, the pressure inside will increase, causing an increase in the volume. At a certain point though the volume will increase too much as to cause a significant decrease in pressure.
• The air molecules will gain kinetic energy, hence (1) increasing the molecules's speed, and (2) heating the air molecules.
Given 1 in=2.54 cm, how many centimeters are in an average hand (9.50 inches) __ cm (3 significant figures)
Answer:
9.5 inches = 24.1 cm
Explanation:
Given that,
1 inch = 2.54 cm
We need covert 9.5 inches to cm. For this we will use unitary method. To convert 9.5 inches to cm multiply 2.54 and 9.5. So,
9.5 inches = (2.54 × 9.5) cm
9.5 inches = 24.13 cm
or
9.5 inches = 24.1 cm
Hence, this is the required solution.
La rapidez a la que cantan los grillos de árbol es de 2.0 ×102 veces por minuto a 27°C, pero es sólo de 39.6 veces por minuto a 5°C. A partir de estos datos, calcule la "energía de activación" para el proceso del canto.
Answer:
51096J/mol = Energía de activación para el proceso del canto
Explanation:
Podemos solucionar este problema usando una forma de la ecuación de Arrhenius:
[tex]Ln\frac{K_2}{K_1} = \frac{-Ea}{R} (\frac{1}{T_2} - \frac{1}{T_1} )[/tex]
Donde K representa la velocidad de reacción (En este caso, la velocidad a la que cantan los grillos), Ea es la energía de activación, R la constante de los gases (8.314J/molK) y T representa la temperatura absoluta de 1, el estado inicial y 2, el estado final.
Estado inicial: K1 = 2.0x10²; T1 = 27°C + 273.15 = 300.15K
Estado final: K2 = 39.6; t2 = 5°C + 273.15 = 278.15K
Reemplazando en la ecuación:
[tex]Ln\frac{39.6}{2.0x10^2} = \frac{-Ea}{8.314J/molK} (\frac{1}{278.15K} - \frac{1}{300.15K} )\\\\-1.6195 = \frac{-Ea}{8.314J/molK}*2.6351x10{-4}K{-1}[/tex]
51096J/mol = Energía de activación para el proceso del canto