If oxygen causes fire to burn, why didn't the world explode when fire burns at a particular place...since oxygen is everywhere...? Explain...
Answer:
Oxygen does not burn. It is not flammable, but it is an oxidizer.
Explanation
I think you are misunderstanding what is meant by "fire burns up air". Fire does use oxygen when it burns. But it also produces carbon dioxide. An oxygen molecule has two oxygen atoms in it. Fires use this to produce carbon dioxide by adding a single carbon atom from the fire’s fuel (wood, for instance).
hope it'll help:)
Which star has the highest surface temperature
A. blue star
B. yellow star
C. white star
D. red star
Answer:
The blue star is the hottest star.
Explanation:
Red stars are cooler than the sun, with surface temperatures of 3,500 K for a bright red star and 2,500 K for a dark red star. The hottest stars are blue, with their surface temperatures falling anywhere between 10,000 K and 50,000 K
Which of the following is a scientific question you could ask about the game
of basketball?
A. Do you enjoy basketball more than volleyball?
B. Which team is this year's best?
C. Which player should be traded to another team?
D. Do teams that practice more win more games?
SUBMIT
The scientific question related to the game of basketball is option D: "Do teams that practice more win more games?"
This question is scientific because it explores a cause-and-effect relationship between practice and game outcomes. It can be investigated through empirical observation and data analysis.
To answer this question, researchers could collect data on the practice hours of different basketball teams and compare them to their corresponding game performance. Statistical analysis could be used to determine if there is a correlation between practice time and winning percentage or other performance metrics.
By examining a large sample of teams over an extended period, researchers could draw conclusions about the impact of practice on game outcomes. This scientific inquiry would contribute to the understanding of the factors that influence team success in basketball and could potentially inform training strategies and coaching techniques.
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Which of the following describes scientists?
О
A. People with only one perspective
B. People with similar personalities
C. People from different backgrounds
D. People with perfect understanding of science
When a single salt crystal is added to a cool liquid, large crystals form. Which statement about the original cool liquid is correct?
A) The liquid is a heterogeneous mixture because the crystals can be easily separated from the liquid
B) The liquid is a pure substance because it was made up of a single compound
C) The liquid is a pure substance because it was uniform before the crystal was added
D) The liquid is a homogenous mixture because the substance that formed the large crystals was uniformly dissolved
The liquid is a homogeneous mixture because the substance that formed the large crystals was uniformly dissolved.
A solution is composed of a solute and a solvent. A solution is a typical example of a homogeneous mixture.
We define a solution as any combination of solute and solvent. A solution can be regarded as a homogeneous mixture since the solute is uniformly distributed throughout the solution. The solute and solvent constitutes one phase.
When a salt crystal is added to the solution, crystallization is induced and large crystals of solute form.
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A salt crystal is a cubic form of sodium chloride that is closely bounded together by the reaction of sodium and chlorine ions during electrovalent bonding.
Taking a look at a heterogeneous mixture;
It refers to the mixtures that are not thoroughly mixed and uniform in composition.
On the other hand, homogeneous mixtures are formed when a substance i.e. solute (here, it is the salt crystal) is being added to a cool liquid(solvent) is thoroughly mixed.
From the given information, we are being told that when this single salt crystal is added to the cool liquid, large crystals are formed.
This implies that the formation of large crystals is brought about by the action of crystaliization rendering the liquid to be a homogeneous mixture.
We can therefore conclude that the correct statement about the original cool liquid is in Option D.
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A toaster has a resistance of 28 Ω and is plugged into a 110 V circuit. Using the GRASS method, what current is measured?
Answer:
The current of the toaster is 3.93A
Explanation:
Using the GRASS method:
G: Given: The information that is given is that we have 28Ω of Resistance and 110V of voltage.
R: Required: We need to find the current measured.
A: Action: We can use Ohm's law that relates resistance, voltage and current in the equation:
V = R*I
Or:
I = V/R
Where I is current in A, V is voltage = 110V and R is resistance = 28Ω
S: Solve:
I = 110V / 28Ω
I = 3.93A
S: Statement:
The current of the toaster is 3.93Ais zinc a basic radical or acid radical?
Answer:
depends on the element it's reacting with..
Explanation:
if the another element requires less energy to loose electron then zinc will become negatively charged and hence becomes acidic radical..
normally if it is reacting with element with valency 4 and Atomic number less than it(Ti,Si,C) then it will lose electron and gain positive sign and henve becomes basic radical..
Which of the following is the BEST choice to contain small amounts of chemicals while they react?
electronic balance
test tube
coffee mug
graduated cylinder
Answer:
test tube
Explanation:
test tube is a very small thin glass in the science lab and it's contain small amount of chemicals as they react
Assess two situations in which it is important to question scientific issues in the media.
Answer:
Claims based on vague statements and statements from non-experts.
Explanation:
Two unknown white, lustrous minerals were tested for hardness and streak. Both had a hardness of 4, and had a white streak. What can you conclude from these tests?
Answer: Fluorite
Explanation: Minerals are naturally occurring inorganic materials with definite chemical compositions and definite physical properties. Hardness and Streak are both physical characteristics used in identifying minerals. The colour of a mineral’s powder defines its streak (it does not change from mineral to mineral) and a streak of white shows that such mineral has a calcium fluoride making it a fluorite. To check streak, one simply scrapes the mineral across an unglazed porcelain plate.
Hardness on the one hand, is the resistance to cutting, scratching, abrasion or indentation of minerals. Mineral hardness is specified by the Mohs hardness scale when working with hand samples, and the scale ranges from 1 (very soft like talc) to 10 (as hard as diamond). A hardness of 4 also put such mineral into the fluorite range indicating that it is harder than calcite, but softer than feldspar.
In conclusion, the tests show that the mineral in question is a fluorite.
lab report evidence of plate motion
Explanation:
There is variety of evidence that supports the claims that plate tectonics accounts for
(1) the distribution of fossils on different continents
,(2) the occurrence of earthquakes, and
(3) continental and ocean floor features including mountains, volcanoes, faults, and trenches.
MARK AS BRAINLIST IF IT IS USEFUL
which of the following will show tyndall effect ?
a. salt solution
b. copper sulphate solution
c. starch solution
d. chalk powder in water
Answer:
Starch solution
Explanation:
Colloidal solutions show tyndall effect and starch solution is a colloidal solution.
cho 6,5 g Zn tác dụng với dung dịch chứa 12g HCl. Thể tích khí H2 ( ở đktc ) là
Answer: nHCl = 12/36,5= 0,38(mol)
nZn = 6,5/65 = 0,1(mol)
Ta có pt: Zn + 2HCl --> ZnCl2 + H2
Vì 2n Zn = 0,2 < n HCl = 0,38 nên HCl dư
Theo PTHH :
n H2 = n Zn = 0,1(mol)
V H2 = 0,1.22,4 = 2,24(lít)
Explanation:
What is the energy of a photon emitted with a wavelength of 448 nm?
O A. 2.97 x 10-22 J
O B. 4.44 x 10-19 J
O C. 8.91 x
10-23 J
O D. 1.48 x 10-27 J
Answer: B is the correct answer
Explanation:
The energy of a photon is 4.44×[tex]10^{-19}[/tex]J for the wavelength of 448 nm.
So, option (B) is correct. This can be calculated by using the energy formula.
The energy of a photon:The energy of a photon is said to be photon energy. It is directly proportional to the photon's electromagnetic frequency and inversely proportional to the wavelength. If the frequency of the photon is high then its energy is also high.
The energy of a photon, E=hc/λ
Given data:Given that,
λ = 448nm
h= 6.63×[tex]10^{-34}[/tex]J/s
Calculating the energy:E = 6.63×[tex]10^{-34}[/tex]×3×[tex]10^8[/tex]/448×[tex]10^-^9[/tex]
E = 4.44×[tex]10^{-19}[/tex] J
Hence option (B) is correct.
Therefore, the energy of a photon emitted with a wavelength of 448nm is 4.44×[tex]10^{-19}[/tex] J.
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define briefly about kilogram
Answer:
it's the SI unit of mass (equivalent to
approximately 2.205 lb), first introduced as a unit of mass for the metric system.
How can the percentage of air be determined
Answer:
The composition of air can be determined by an experiment which includes passing a known volume of air, measured at a known temperature and pressure, over sufficient amount heated copper granules/powder, and measuring the volume gas remaining after the gas cools down to the temperature at which the first measurement was taken
Oxygen reacts with copper according to the following chemical reaction
2Cu (s) + O₂ (g) → 2CuO (s)
Cupper does not react with the other constituents of air
Whereby the initial volume of air was 100 cm³, we have;
Percentage of oxygen in air = 100 - The final volume reading of the container initially holding the air
When done using am appropriate experimental setup, the percentage of gases remaining equals 79% to 80%, therefore, the percentage composition of oxygen in air is between 20 and 21 percent
Explanation:
Which type of monomer combines and forms nucleic acids?
A. Nucleotide
B. Nitrogenous base
C. Amino acid
D. Monosaccharide
Answer:
A. Nucleotide
Explanation:
Nucleotides are the monomers that make up nucleic acids, such as DNA and RNA.
¿Qué ocurre cuando la radiación del sol atraviesa la atmósfera?
La luz es la fuente de energía y radiación que recibe la Tierra desde el espacio. De toda la energía que entra a la atmósfera una parte es absorbida y otra reflejada. Tanto el aire con sus partículas y moléculas gaseosas como la superficie terrestre (suelo, ciudades, bosques, mares, hielo, etc.) absorben y reflejan en diferente proporción la energía radiante entrante.
Asumiendo, que al tope (última capa) de la atmósfera llega un 100% de la radiación solar, de este total, un 20% es absorbido por las nubes y gases atmosféricos, pero también la atmósfera refleja al espacio un 6%, las nubes reflejan un 20% y el suelo refleja un 4%. El porcentaje de energía restante es absorbida por la superficie de la Tierra (¿cuánto es?).
4. Representar gráficamente los valores y la dirección de las energías radiantes absorbidas y reflejadas a partir de un valor total de energía solar entrante a la atmósfera igual al número de la suma de su fecha de nacimiento asignada previamente en unidades de vatios por cada metro cuadrado (W/m2).
Ejemplo: energía solar entrante = 2.026 W/m2
Asuma que a la atmósfera llega un 100% de la radiación solar (el valor corresponde a la suma de su fecha de nacimiento), de este total, un 20% es absorbido por las nubes y gases atmosféricos, pero también la atmósfera refleja al espacio un 6%, las nubes reflejan un 20% y el suelo refleja un 4%. El porcentaje de energía restante es absorbida por la superficie de la Tierra (¿cuánto es?).
Under certain conditions, the substance mercury(II) oxide can be broken down to form mercury and oxygen. If 24.1 grams of mercury(II) oxide react to form 22.3 grams of mercury, how many grams of oxygen must simultaneously be formed? Grams oxygen
Answer:
1.76 g
Explanation:
2HgO(s) ==> 2Hg(l) + O2(g)
Number of moles of Hg = 22.3 g/ 201g/mol
= 0.11 moles
From the reaction equation;
2 moles of Hg is formed alongside 1 mole of oxygen
Hence;
0.11 moles of Hg forms 0.11 moles × 1/2
= 0.055 moles of oxygen
Mass of oxygen formed = 0.055 moles of oxygen × 32g/mol = 1.76 g
Read the chemical equation.
2H2 + O2 → 2H2O
Which of the following statements would be correct if one mole of H2 was used in this reaction?
One mole of oxygen was used in this reaction.
Two moles of oxygen were used in this reaction.
One mole of water was produced from this reaction.
Two moles of water were produced from this reaction.
WILL MARK BRAINLIST
Answer:
One mole of water was produced from this reaction.
Explanation:
According to this question, the following equation is given as follows:
2H2 + O2 → 2H2O
Two (2) moles of hydrogen gas produces two (2) moles of water in this balanced chemical equation.
If 1 mole of hydrogen gas was used, then:
1 × 2/2 moles of water would be produced
1 mole of water would be produced.
Answer:
One mole of water was produced from this reaction.
Explanation:
Guy above me is right
PLZ HELP ME WITH MY WORK
Answer:
It should be the answer D. A type of atom
Explanation:
A model is a "synthetic coordination entity that closely approaches the properties of a metal ion in a protein"
An ion is a charged atom.
One way of producing drinking water from seawater is by reverse osmosis.
Reverse osmosis is a type of filtration. Seawater is pushed through a semi-permeable membrane. Pressure is applied to the seawater. Semi-permeable
means salt is trapped on one side of the membrane, but water can pass through.
The trapped salts form a ‘seawater concentrate’ on one side of the membrane.
Where do the trapped salts go?
[a] ocean [b]Water distribution system
[c]Storage tank [d]delivery pipeline
QUESTION 3:
Based on the above picture what will determine whether a particle is able to pass
through the membrane?
[a] particle size [b] particle mass
[c] number of particles [d] charge on the particle
the trapped salts go to seawater concentrate
describe the process to electroplating with the help of an activity
Answer:
process of depositing a thin layer of any superior metal over an object of a cheaper metal, with the help of electric current
Explanation:
I hope this help have an great day and stay health
Question 4. Thanks !!
Answer:
the shape would be square planar.
Explanation:
From the question, we can see that the electron geometry is octahedral. Removing the two axial bonds to fit the description, and we have a square planar structure.
What information does the percent composition of an atom in a molecule
give?
A. The relative number of atoms one element contributes to a
molecule
B. The relative amount of mass an atom contributes to a molecule
C. The total mass that element contributes to a molecule
D. The total number of atoms of that element in a molecule
C.
This is basically the definition of percent composition which is how much mass a element contributes to a specific molecule.
Answer: B.
Explanation:
the relative amount of mass an atom contributes to a molecule
A cactus needle is a structure made of different tissues that work together to protect the plant from animals that might want to eat it. What level of body organization does a cactus needle represent?
A. Cell
B. Organ
C. Cell system
D. Body system SUBMIT
Calculate the amount (in moles) of gas which occupies 250cm³ at STP
Answer:
0.01
Explanation:
volume of 22.4 L (22,400 ml) at s.t.p. 250 ml out of 22,400 ml is 0.01 rounded, therefore I assume that is the answer. About 0.01 mole occupies 250 cm3 at s.t.p.
yall what do ya think shaped ya feelings bout science classes?
I was interested in science when I first saw a diagram of Solar system in my sister's geography book. At that time I was in Senior Kindergarten and she was in 6th grade. At first, I was just interested in space, universe and black holes stuff, but then as I started learning more, I realised how amazing other branches of science are too. They are so systematic. What encourages me to learn more are the gaps in science, its mysteries, I wish to uncover them one day, and for that I am preparing myself. When I am in a science class, I try to imagine where can I apply this knowledge in my day to day life, and my teachers are fascinated when I ask them if this principle is responsible for this phenomena. I love it very much. I like Physics the most, but other branches are great too.
Mike is gathering equipment for a lab where he will measure the masses of various
chemicals. Which of the following is the most complete list of the equipment he will
need?
electric balance, graduated cylinder, test tube
graduated cylinder test tube, goggles
O graduated cylinder beaker, test tube
electric balance, goggles, beaker
Answer:
electric balance, goggles, beaker
Explanation:
I did it and got it right
1. El genotipo es el conjunto de alelos que posee un individuo, y cuando dos alelos son idéntica
heterocigoto para ese locus.
a Falso
b Verdadero
2. En genética se utilizan letras para representar los alelos de las caracteristicas hereditarias,
mayúscula representa el alelo recesivo y la letra minuscula representa al alelo dominante.
Falso
b. Verdadero
a
3. Usualmente los cruces se presentan en un cuadro de Punnett, y ayuda a determinar la probat
de un genotipo y fenotipo en particular
a Falso
b. Verdadero
4. Para corroborar un genotipo a partir del fenotipo, Mendel realizó cruces de prueba, esto es p
conociendo la dominancia y el genotipo de un progenitor
Falso
b. Verdadero
a
5. Las mutaciones pueden ser heredables debido a que ocurren a nivel genético
a Falso
b. Verdadero
C. Tareas de la semana
1. Cruce monohibrido (50%)
Elabora el cruce de dos organismos heterocigotos: Aa x Aa. Donde: A - verde, a - rojo
. Coloca los resultados
Gametos
А a
• Determina la frecuencia genotipica y fenotipica
Frecuencias fenotipica Frecuencias genotipica:
X-4 Homocigotos
x:4 heterocigotos
Verde:
Rojo
А
a
I
El genotipo es el conjunto de información genética en un organismo, y se encuentra codificado en el ADN en su secuencia de bases. Dicha información se expresa mediante síntesis de proteínas.
1. Los genes son unidades de herencia pues almacenan la información genética. El conjunto de genes de una especie se denomina genoma. Cada gen ocupa en el cromosoma una determinada posición, denominada locus. Para cada locus hay dos tipos o formas de genes, llamados alelos. Los mismos pueden ser iguales (siendo el organismo homocigota para ese locus) o distintos (heterocigota). Entonces, la respuesta es "b: Verdadero"
2. Los alelos dominantes, se representan con letras mayúsculas mientras que los alelos recesivos se representan con letras minúsculas. Ejemplo, el alelo que codifica para el color de ojos marrones puede ser dominante (se puede representar con la letra A, por ejemplo), mientras que el alelo que codifica para ojos verdes puede ser recesivo (a). Un individuo cuyo genotipo es Aa, tendrá ojos marrones ya que el alelo dominante enmascara los efectos del alelo recesivo. Un individuo AA también tendrá ojos marrones pues es el único alelo presente. Sin embargo, un individuo aa tendrá ojos verdes ya que tiene ambos alelos recesivos que se expresan. Entonces, la respuesta es "a: Falso"
3. Un cuadro de Punnett es un diagrama utilizado para determinar la probabilidad de obtener descendencia con un determinado fenotipo (características visibles) y genotipo (conjunto de genes). Permite utilizar genotipos maternos y paternos con sus alelos dominantes y recesivos , para cruzarlos y realizar el análisis. Entonces, la respuesta es "b: Verdadero"
4. Mendel realizó un experimento para estudiar los genes de la planta de guisantes. Cruzó una plantas de dos variedades distintas (gigantes y enanas), espolvoreando el polen de una sobre el pistilo de otra. Observó que en la primera generación de descendencia, habían todas plantas gigantes y no de tamaño "intermedio" Luego de esto, entendió que había una característica dominante para el tamaño gigante de una planta, y una recesivo para el tamaño enano. Pero previamente a todo esto, no conocía la dominancia ni el genotipo de los progenitores. Entonces, la respuesta es "a: Falso"
5. Una mutación es una alteración azarosa o por acción de un mutágeno en el ADN, ya sea en su secuencia de bases o en su organización. Esto hace que se produzca una variación en las características del organismo, que puede o no transmitirse a una descendencia. Una mutación genética hereditaria ocurre en las gametas femeninas (óvulo) y/o masculinas (espermatozoide). Cuando ocurre la fertilización, se crea un cigoto que dará lugar a un nuevo organismo que portará la mutación. Entonces, la respuesta es "b: Verdadero"
1. Cruce entre Aa x Aa
siendo A: verde, a: rojo
Cada genotipo, en este caso ambos Aa, representa los genes de un organismo. Sin embargo, en el cuadro de Punnett, se utilizan las gametas producidas por los mismos organismos. Cada gameta solo posee un alelo de cada gen, ya que son haploides. Entonces los organismos con genotipo Aa, pueden producir gametas A o a. (Ver archivo adjunto)
Como se puede ver en el cuadro, hay un 25% de probabilidades de obtener descendencia con genotipo AA (verde), 25% para aa (rojo) y 50% para Aa (verde). Lo mismo se puede expresar como 2:1:1 (de un total de 4, 2 son Aa, 1 es AA y 1 es aa). Recordando que el alelo A es dominante sobre a, la frecuencia fenotípica será de 75% verde y 25% rojo, lo que se puede expresar como 3:1 (de un total de 4, 3 son verdes y 1 es rojo).
Para concluir, recordemos que los genes codifican para las características visibles (fenotipo), y el conjunto de genes forma el genotipo. Para cada gen, hay dos alelos que ocupan un determinado locus o posición en el cromosoma y los mismos pueden ser dominantes o recesivos. Para estudiar esto, se pueden utilizar cuadros de Punnett en donde se cruzan organismos maternos y paternos, conociendo sus genes para así determinar el posible genotipo y fenotipo de la descendencia que puedan tener. Aunque hay que considerar que puede ocurrir una mutación en sus gametas, que se herede y afecte los genes y las características visibles.
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