four
Explanation:
four significant figures in 0.4004 ml
Graphite is a form of____.
A. Galena
B. Corundum
C. Chalcopyrite
D. Carbon
E. Bauxite
Answer:
D. Carbon
Explanation:
Graphite, archaically referred to as plumbago, is a crystalline form of the element carbon with its atoms arranged in a hexagonal structure. You'll get the substance when carbon is stacked in sheets. It occurs naturally in this form and is the most stable form of carbon under standard conditions. Under high pressures and temperatures, it converts to diamond. Graphite is used in pencils and lubricants. It is a good conductor of heat and electricity. Its high conductivity makes it useful in electronic products such as electrodes, batteries, and solar panels.
A 1.87 mol sample of Ar gas is confined in a 45.5 liter container at 23.6 °C.
If the temperature of the gas sample is raised to 46.1 °C holding the volume constant, the average kinetic energy will
a. increase
b. remain the same
c. not enough information to answer the question
d. decrease
Answer:
a. increase
Explanation:
Based on the kinetic molecular theory of gases, the average kinetic energy of the system will increase.
The average kinetic energy is heat If temperature increases, heat of a system will also rise. According the kinetic molecular theory "the temperature of the gas is a measure of the average kinetic energy of the molecules"Therefore, due to the increase in temperature, the average kinetic energy of the system increases.
write the correct formulas that indicate only a physical change has taken place
1. 2NaCl + MgO -->
2. 2H2 + O2 -->
2NaCl + MgO → Na₂O + MgCl₂ and 2H₂ + O2 →2H₂O the correct formulas that indicate only a physical change has taken place
In a chemical reaction, there is a change in the composition of the substances in question; in a physical change there is a difference in the appearance, smell, or simple display of a sample of matter without a change in composition
2NaCl + MgO → Na₂O + MgCl₂ has change the color as well as appearance and in the 2H₂ + O2 →2H₂O has also change in the physical changes
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11. (03.03 MC)
What best describes the bonding in a water molecule? (5 points)
O An oxygen atom shares an electron pair with each H atom.
O An oxygen atom shares a single electron with each H atom.
) An oxygen atom receives an electron from each H atom.
O An oxygen atom transfers an electron to each H atom.
Answer:
A) An oxygen atom shares an electron pair with each H atom.
Explanation:
one studrnt rubs a balloon against his hair several times. Another student passes a comb through her hair several times. The students place the comb near the balloon and observe that the comb repels the balloon. Which is the most likely reason the comb is able to repel the balloon?
TIME REMAINING 02:39:32 Carla draws two circuit diagrams that connect the same components in different ways, as shown. Which statement about the circuits is correct? The total resistance in Circuit A is greater than that in Circuit B. When a bulb in Circuit A goes out, the other bulbs keep shining. The bulbs in Circuit A shine brighter than those in Circuit B. When a bulb in Circuit B goes out, the other bulbs go out.
Answer: The total resistance in Circuit A is greater than that in Circuit B.
Explanation:
The statement which is true about the circuit is that the total resistance in Circuit A is greater than that in Circuit B.
What is circuit?An electronic circuit comprises of individual electronic components like resistors, diodes,transistors , capacitors,etc. which are connected to each other by means of wires through which electric current flows.It can also be referred to as an electronic circuit.
It usually comprises of at least one active component . The combination of wires and simple and complex components allows operations to be performed, amplification of signals, displacement of data and performing of computations.
There are three types of circuits , an analog circuit ,a digital circuit and a mixed circuit which is combination of digital and analog circuits , even semiconductors are used in circuits.
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____ is a gemstone used in clocks and watches.
A. Carbon
B. Chalcopyrite
C. Quartz
D. Corundum
E. Galena
Answer: C
Explanation:
Clocks and watches are made out of Quartz
Non-living factors in an ecosystem are ______.
A. biotic
B. abiotic
C. antibiotic
PLEASE HELP!!!
Answer:
B. abiotic
Explanation:
in biology and ecology, abiotic components or abiotic factors are non living chemical and physical parts of the environment that affect living organisms and the functioning of ecosystems.
What is the molarity of a solution prepared by dissolving 1.25g of HCl gas
into enough water to make 30cm3 of solution
The molarity of a solution : 1.13 M
Further explanationMolarity shows the number of moles of solute in every 1 liter of solute or mmol in each ml of solution
[tex]\large \boxed {\bold {M ~ = ~ \dfrac {n} {V}}}[/tex]
Where
M = Molarity
n = Number of moles of solute
V = Volume of solution
mass HCl = 1.25 g
mol HCl(MW=36.5 g/mol) :
[tex]\tt mol=\dfrac{mass}{MW}\\\\mol=\dfrac{1.25}{36.5}\\\\mol=0.034[/tex]
Volume of solution = 30 cm³ = 0.03 L
The molarity :
[tex]\tt M=\dfrac{0.034}{0.03}\\\\M=1.13[/tex]
One of your classmates tells you, “Since atoms are the basic building blocks of matter, all atoms have to be the same. Do you agree or disagree with this statement? Explain your reasoning.
e. A 10kg iron plate contains 2000J potential energy at a height cal Find out its height. A/S,
The height of the given iron plate is 20.41m
Potential energy is the energy that is acquired by an object due to its position or configuration. If we consider that 'm' to be the mass of the object and it is placed at a height 'h' above the horizontal surface, then the P.E. , 'P' of the thing is given by the equation:
P = mgh
where, g is that the acceleration due to gravity.
From the above equation height could be calculated as:
h = P /mg
From the question it might be clearly seen that,
P = 2000 J ; m = 10 Kg and allow us to consider g = 9.8 m/s²
h = 2000 / (10 * 9.8)
∴ h = 20.41 m
Therefore, the height of the given iron plate is 20.41m
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measurements also show that a certain sample of the unknown compound contains of nitrogen and of oxygen. write the complete chemical formula for the unknown compound.
The chemical formula is the representation of the atoms of the molecule and compound involved in the reaction. The chemical formula for oxygen and nitrogen-containing atoms are N₂O₃.
What is the chemical formula?Chemical formulas are the representation of the coefficients or proportions of the atoms of the elements involved in the molecule or the chemical compound. It uses letters, symbols, numbers, arrows, etc.
Given,
Moles of oxygen = 6.2 mol
Moles of nitrogen = 4.1 mol
The moles of oxygen and nitrogen are divided by 4.1 as it is the smallest number:
N ÷ O = (4.1 ÷ 4.1) ÷ (6.2 ÷ 4.1)
= 1 ÷ 1.5
= 2 : 3
Therefore, N₂O₃ is the chemical formula.
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Your question is incomplete, but most probably your full question was, Measurements also show that a certain sample of the unknown compound contains 6.2 mol of oxygen and 4.1 mol of nitrogen. Write the complete chemical formula for the unknown compound.
what are reactivity trends
Answer:
Explanation:
Major periodic trends include: electronegativity, ionization energy, electron affinity, atomic radius, melting point, and metallic character. Periodic trends, arising from the arrangement of the periodic table, provide chemists with an invaluable tool to quickly predict an element's properties.
Use the periodic table above to help you compare the elements cesium (Cs, #55) and Calcium (Ca, #20). Which of the following statements is true about the valence electrons of these two elements? (1 pt)
*
1 point
Cesium has more valence electrons and they are in a higher energy level than calcium's valence electrons.
Cesium has fewer valence electrons but they are in a higher energy level than calcium's valence electrons.
Cesium has more valence electrons and they are in a lower energy level than calcium's valence electrons.
Cesium has fewer valence electrons and they are in a lower energy level than calcium's valence electrons.
The statement which is true about the valence electrons of cesium and calcium is as follows:
Cesium has fewer valence electrons but they are at a higher energy level than calcium's valence electrons.Thus, the correct option for this question is B.
What are Valence electrons?
Valence electrons may be defined as the number of electrons that are present in the outermost shell of any element. For example, Sodium has an atomic number of 11. Its electronic configuration is 2, 8, and 1. Here, one electron is present in the outermost shell, so, sodium has only one valence electron.
According to the electronic configuration, it is found that cesium has only one valence electron, while calcium has two. So, the number of valence electrons is more in calcium as compared to cesium.
But, the valence electron found in cesium is at a higher energy level due to the completed d-orbital.
Therefore, the correct option for this question is B.
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In a chemical reaction, it is the action of the___that is responsible for the changes taking place.
A. Protons
B. electrons
C. atoms
D. neutrons
Which of the following is not a product of cellular respiration?
a. CO2
b. Energy
c. C6H1206
d. H2O
Please select the best answer from the choices provided
Ο Α
ОВ
Ос
OD
Answer:
C
Explanation:
In the chemical equation of cellular respiration, C₆H₁₂O₆ is not a product of cellular respiration.
What is chemical equation?
Chemical equation is a symbolic representation of a chemical reaction which is written in the form of symbols and chemical formulas.The reactants are present on the left hand side while the products are present on the right hand side.
A plus sign is present between reactants and products if they are more than one in any case and an arrow is present pointing towards the product side which indicates the direction of the reaction .There are coefficients present next to the chemical symbols and formulas .
The first chemical equation was put forth by Jean Beguin in 1615.By making use of chemical equations the direction of reaction ,state of reactants and products can be stated. In the chemical equations even the temperature to be maintained and catalyst can be mentioned.
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mass number is the number of protons and neutrons in the nucleus of an isotope . how many electrons in an oxygen-18 atom ?
Answer:
In neutral oxygen atom 8 electrons are present
Explanation:
Physical properties of reactants: Physical properties of products: 12.
When you mix baking soda (a white powder) and vinegar (a clear liquid), you produce carbon dioxide gas. Describe the properties of the reactants and products to show that a chemical change has occurred.
Answer: The reactants are baking soda and vinegar. Baking soda is a white powder, and vinegar is a clear liquid. The products of this reaction are carbon dioxide, water, and sodium acetate. Carbon dioxide is a colorless gas, water is a colorless liquid, and sodium acetate is a white crystalline powder.
A chemical change can be seen in how the molecular formulas of the products are different from the reactants, since the reactants have chemically changed into completely different molecules.
Hope this helps
What are the 7 diatomic elements?
Answer: Hydrogen, Nitrogen, Flourine, Oxygen, Iodine, Chlorine and Bromine
Explanation:
A household cleaner has a pH around 10. It would be considered
a base.
an acid.
neutral.
a liquid.
describe beta and gamma radiation
Answer:
"Alpha radiation is the name for the emission of an alpha particle in fact an helium nuclei, beta radiation is the emission of electrons or positrons , and gamma radiation is the term used for the emission of energetic photons
Answer:
Alpha radiation is the name for the emission of an alpha particle in fact an helium nuclei, beta radiation is the emission of electrons or positrons , and gamma radiation is the term used for the emission of energetic photons.
Explanation:
Gamma Radiation
Frequently, gamma ray production accompanies nuclear reactions of all types. In the alpha decay of U-238, two gamma rays of different energies are emitted in addition to the alpha particle.
U92238→He24+Th90234+2γ00(17.3.4)
Virtually all of the nuclear reactions in this chapter also emit gamma rays, but for simplicity the gamma rays are generally not shown. Nuclear reactions produce a great deal more energy than chemical reactions. Chemical reactions release the difference between the chemical bond energy of the reactants and products, and the energies released have an order of magnitude of 1×103kJ/mol. Nuclear reactions release some of the binding energy and may convert tiny amounts of matter into energy. The energy released in a nuclear reaction has an order of magnitude of 1×1018kJ/mol. That means that nuclear changes involve almost a million times more energy per atom than chemical changes!
Beta radation
Beta radiation consists of high energy electrons emitted from the nucleus. These electrons have not come from the electron shells or energy levels around the nucleus. Instead, they form when a neutron splits into a proton and an electron.
Characteristics of Beta Radiation
Key characteristics of beta radiation are summarized in following points:
Beta particles are energetic electrons, they are relatively light and carry a single negative charge.
Their mass is equal to the mass of the orbital electrons with which they are interacting and unlike the alpha particle a much larger fraction of its kinetic energy can be lost in a single interaction.
Their path is not so straightforward. The beta particles follow a very zig-zag path through absorbing material. This resulting path of particle is longer than the linear penetration (range) into the material.
Since they have very low mass, beta particles reach mostly relativistic energies.
Beta particles also differ from other heavy charged particles in the fraction of energy lost by radiative process known as the bremsstrahlung. Therefore for high energy beta radiation shielding dense materials are inappropriate.
When the beta particle moves faster than the speed of light (phase velocity) in the material it generates a shock wave of electromagnetic radiation known as the Cherenkov radiation.
The beta emission has the continuous spectrum.
A 1 MeV beta particle can travel approximately 3.5 meters in air.
Due to the presence of the bremsstrahlung low atomic number (Z) materials are appropriate as beta particle shields.
an element has an atomic number of 47 and 50 neutrons. What is the element's symbol?
Answer:
Silver Ag
Explanation:
People sometimes talk about seeing shooting stars. What do they actually see?
Answer:
A ball of gas flying or a meter...
Explanation:
compare LPG and CNG as a fuel with coal
I NEED HELP ASAP ILL GIVE 10 POINTS
6. Experiments are usually conducted one time and by one team to speed
up the scientific process.
True
False
Answer: false
Explanation:
which of the four cars had the least net force applied to it when it was launched down the ramp
The least net force applied : Car 3(12 N)
Further explanationNewton's 2nd law explains that the acceleration produced by the resultant force on an object is proportional and in line with the resultant force and inversely proportional to the mass of the object
∑F = m. a
Car 1 ⇒m=0.5 kg, a=36 m/s²
[tex]\tt \sum F=0.5\times 36=18~N[/tex]
Car 2⇒m=0.8 kg, a=50 m/s²
[tex]\tt \sum F=0.8\times 50=40~N[/tex]
Car 3⇒m=0.6, a=20 m/s²
[tex]\tt \sum F=0.6\times 20=12~N[/tex]
Car 4⇒m=1, a=19~m/s²
[tex]\tt \sum=1\times 19=19~N[/tex]
Complete the nuclear equation
42 K → 0 e
19____-1
Answer:
42 19 K→42 20 Ca+e−
Explanation:
Naturally-occurring potassium atoms have a weighted average atomic mass of 39.10 (as seen on most modern versions of the periodic table.) Each potassium atom contains 19 protons p+ and thus an average potassium atom contains about 39.10−19≈20 neutrons n0.
This particular isotope of potassium-42 contains 42 nucleons (i.e., protons and neutrons, combined;) Like other isotopes of potassium 19 out of these nucleons are protons; the rest 42−19=23 are therefore neutrons.
Which statement describes Newton’s law of universal gravitation?
Mass has little effect on gravity between objects.
Gravity pushes objects away from Earth’s center.
Gravity does not act between Earth and the moon.
Every object in the universe attracts every other object.
Answer: Its D the last one.
Explanation:
Answer: I believe it’s d but I will come back and tell you if it’s wrong
Explanation:
13. (03.02 LC)
Which layer is between the crust and the asthenosphere? (7 points)
O LIthosphere
O Mesosphere
O Outer core
O Inner core