what is quartz made of
Determine the number of moles of a gas which occupies 39.0mL at 27°C if the pressure is 107 kPa.
3.14 x 10-3 mol
5.52 x 10-3 mol
2.45 x 10-3 mol
1.67 x 10-3 mol
Which scientist arranged the elements in order of increasing atomic number, rather than increasing atomic mass? Antoine Lavoisier Dmitri Mendeleev Henry Moseley John Newlands
The answer is: Henry Moseley.
Henry Gwyn Jeffreys Moseley (1887–1915) proposed that the number of positive nuclear charges (protons) in atom is equal to its atomic number in the periodic table.
Mendeleev did not know about isotopes and he arranged the elements in order of increasing relative atomic mass.
For example, positions of iodine and tellurium were reversed in Mendeleev's table, because of different isotopes, but Moseley solved anomalies like this one.
Demonstrate your knowledge of waves.Describe the difference between mechanical and electromagnetic waves. Give an example of each kind of wave related to telecommunications. Answer using complete sentences and key vocabulary
PLEASE HELP
There are some methods that differentiate waves; one thing is by its medium. Electromagnetic waves did not require a medium for transmission such as in a vacuum while mechanical waves require a medium to travel such as air, water or anything that can serve as a transmission aid.
The most common sample of EM waves in telecommunication is radio, light and infra-red signals. An example of a mechanical wave is a sound wave, which requires air to travel. Oscillating molecules made the sound waves.
Which is the correct symbol for the atom with 42 protons and 49 neutrons?
Explanation:
Number of protons present in an atom are actually the atomic number of atom. Each element will have different atomic number.
Hence, each element is different in nature. On the other hand, atomic mass is the sum of number of protons and number of neutrons present in an element.
For example, Molybdenum is the element with 42 protons and 49 neutrons. Molybdenum is represented by the symbol Mo.
Therefore, we can conclude that Mo is the correct symbol for the atom with 42 protons and 49 neutrons.
The correct symbol for the atom with 42 protons and 49 neutrons is ^91Mo.
Atomic notation explained.
The correct symbol for the atom with 42 protons and 49 neutrons is ^91Mo.
In atomic notation, the image for an component consists of the nuclear number (number of protons) as a subscript and the mass number (entirety of protons and neutrons) as a superscript.
For the given atom with 42 protons and 49 neutrons, the overall mass number is 42 + 49 = 91. Hence, the image for this particle is ^91Mo, speaking to the component Molybdenum (Moment) with a mass number of 91.
Learn more about atomic notation below.
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An aqueous solution contains 0.100 m naoh at 25.0 °c. the ph of the solution is ________.
An aqueous solution contains 0.100 m NaOH at 25.0 °C. the pH of the solution is 13.00
To determine the pH of a 0.100 M NaOH solution, we need to understand that NaOH is a strong base and dissociates completely in water. The concentration of hydroxide ions (OH-) in the solution will be equal to the concentration of NaOH, which is 0.100 M.
The pOH of the solution can be calculated using the formula:
[tex]\[ \text{pOH} = -\log[OH^-] \][/tex]
where [tex]\([OH^-]\)[/tex] is the concentration of hydroxide ions.
Given that [tex]\([OH^-] = 0.100\)[/tex] M, we can calculate the pOH as follows:
[tex]\[ \text{pOH} = -\log[0.100] \][/tex]
[tex]\[ \text{pOH} = -(-1) = 1 \][/tex]
At 25.0 °C, the pH and pOH of a solution are related by the equation:
[tex]\[ \text{pH} + \text{pOH} = 14.00 \][/tex]
Using the calculated pOH, we can find the pH:
[tex]\[ \text{pH} = 14.00 - \text{pOH} \][/tex]
[tex]\[ \text{pH} = 14.00 - 1 \][/tex]
[tex]\[ \text{pH} = 13.00 \][/tex]
#1: Which of the following scientists came up with the first widely recognized atomic theory?
A. John Dalton
B. Antione Lavoisier
C. Robert Millikan
D. J.J. Thomson
***My answer: A. John Dalton
is that right??,
Which of the following accurately describes the behavior of water when subjected to temperature change?
A. A mass of water will expand if heated from 0°C to 2°C.
B. The volume of water will increase if cooled from 3°C to 2°C.
C. The volume of water will decrease if heated from 6°C to 7°C.
D. A mass of water will contract if cooled from 1°C to 0°C.
The answer option which accurately describes the behavior of water when subjected to temperature change is: B. The volume of water will increase if cooled from 3°C to 2°C.
Water refers to a liquid molecule that is typically made up of two (2) main chemical elements in the following proportion;
Two atoms of hydrogen.One atom of oxygen.Generally, the volume of water is directly proportional to its temperature.
Hence, an increase in the temperature of water causes the volume of water to increase because its molecules gain energy and move more rapidly, which in turn makes the water molecules to be further apart.
When water is cooled, it contracts (decrease in volume) until a temperature of approximately four degree Celsius (4°C) is reached and then it begins to expand (increase in volume) at lower temperatures (3°C to 2°C), until it reaches its freezing point, which is typically at zero degree Celsius (0°C).
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Why is oxygen called a gas. Give two reasons.,
Why carbontetra chloride exist in liquid form at room temperature?,
2H2S + 3O2 mc008-1.jpg 2SO2 + 2H2O Which option gives the correct mole ratios?
is the aswer H2S:SO2=2:2 and O2:H2O=3:2
If a solution containing 51.429 g of mercury(ii) perchlorate is allowed to react completely with a solution containing 16.642 g of sodium sulfate, how many grams of solid precipitate will be formed?
A transverse and longitudinal wave combine to form __________. a sound wave a radio wave a surface wave an electromagentic wave
#1: In an icy glass of lemonade, which of the following is the solvent?
A. lemon juice
B. ice
C. sugar
D. water
**my answer: D. water
is that right? :/ @chmvijay :)
In a solution, there are two components that is solvent and solute. Solute is one that is dissolved and solvent is one in which is used for dissolving solute or it can be said that it is the which is used for dissolving. So in the icy glass of lemonade, there is a substance that is used for dissolving solute and it will be water as it is used for dissolving solute.
In general, in which direction do convection cells in Earth's atmosphere move heat around the planet?
A. clockwise along the jet streams
B. from the equator toward the poles
C. from the surface to the upper atmosphere
D. from east to west, along with the westerlies,
Connect It Imagine that you can see the particles of ice, liquid water, and water vapor. Describe how these three states of water differ.
Lightning is a very large flow of electrical energy. Describe the type of energy that creates the electrical energy.
A) The electrical energy comes from the thermal energy stored up in the water molecules.
B) The electrical energy comes from the gravitational potential energy of the water molecules.
C) The electrical energy comes from the chemical potential energy of the water molecules in the clouds.
D) The electrical energy comes from the attraction between charges in the cloud and the ground creating an electric potential.
During lightning, the electrical energy comes from the attraction between electrical charges in the cloud and the ground generating an electric potential. Therefore, option (D) is correct.
What is lightning?Lightning can be described as a naturally occurring electrostatic discharge in which two electrically charged regions, both in the atmosphere and the ground, temporarily neutralize themselves, causing the instantaneous release of energy.
Lightning occurs when the negative charges of electrons in the bottom of the cloud are attracted to the positive charges of the protons in the ground.
This discharge creates a wide range of electromagnetic radiation, from the heat created by the rapid movement of electrons, to brilliant flashes of visible light.
Lightning causes a sound of the shock wave which produces gases in the vicinity of the discharge experiencing an instant increase in pressure. Lightning takes place during thunderstorms as well as other kinds of energetic weather systems.
Therefore, the electrical energy during lightning produces the attraction between electrical charges in the cloud.
Learn more about lightning, here:
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here are approximately 15 milliliters (mL) in 1 tablespoon (tbsp).
Which expression can be used to find the approximate number of milliliters in 3 tbsp?
1 tbsp x 15ml/3tbsp
1 tbsp x 3ml/15tbsp
3tbsp x 1 tbsp/15ml
3tbsp x 15ml/1tbsp
Answer:
The correct option is 3tbsp x 15ml/1tbsp
Explanation:
According to the question, 15 milliliters (mL) is equivalent to 1 tablespoon (tbsp), how many milliliters will be equivalent to 3 tablespoons. Let use "X" as the unknown number of milliliters.
If 15 milliliters ⇒ 1 tablespoon
X milliliters ⇒ 3 tablespoons
cross multiply
15 mL × 3 tbsp ⇒ 1 tbsp × X mL
X mL = 15 mL × 3 tbsp/1 tbsp
Which metal atom below cannot form a cation of several different charges?
When one atom of sodium (Na) combines with one atom of fluorine (F), they form the compound sodium fluoride (NaF). Which of the following best describes the arrangement of valence electrons in a bond between Na and F?
1. The valence electrons are shared equally between Na and F.
2. The valence electrons spend more time around the atom of Na.
3. The valence electrons spend more time around the atom of F.
4. The valence electrons are given up by the Na and gained by the F.
Answer:
4. The valence electrons are given up by the Na and gained by the F.
Explanation:
Sodium and fluorine bond ionically, they do not share electrons. Instead, ionic bonding involves the each atom of the metal, sodium, giving up its one electron in it's valence shell to each atom of the non-metal, fluorine.
magnesium reacts with aluminum chloride. if you have 40g of each, how many grams of Al can you make? what is the LR? how much excess is left over after the reaction takes place
At room temperature, the surface tension of water is 72.0 mJ·m–2. What is the energy required to change a spherical drop of water with a diameter of 1.20 mm to five smaller spherical drops of equal size? The surface area of a sphere of radius r is 4π r2 and the volume is 4π r3/3.
An unknown compound has the empirical formula CH2O and a molecular mass of 180 amu. What is the molecular formula of the compound
I need help, the longer I look at this question the more I confuse myself!!!
Consider the unbalanced equation:
HC2H3O2 (aq) +Ba(OH)2 (aq) --> H2O (l) +Ba(C2H3O2)2 (aq)
balance the equation and determine how many moles of Ba(OH)2 are required to completely neutralize 0.461 mole of HC2H3O2.
What happens to the temperature of a thermometer near an endothermic reaction?
What are 3 things you can do to increase the rate of dissolving?
How does a volcano form?
Balance equation Al(s)+__CuSO4(aq) = ____Al2(SO4)3(aq)+____Cu(s)
What is the pressure exerted by 3.00 mol of ar gas with a volume of 50.0 l at 25.0ºc (298.2 k)?
Which of the following atomic numbers represent an element that is radioactive on the periodic table.
The atomic number that represents a radioactive element is N = 100.
Therefore, the correct answer is option 4: N = 100.
To determine which of the given atomic numbers represent a radioactive element, we need to look at the periodic table and identify elements with atomic numbers corresponding to known radioactive elements.
1. N = 11 corresponds to sodium (Na), which is not radioactive.
2. N = 56 corresponds to barium (Ba), which is not radioactive.
3. N = 81 corresponds to thallium (Tl), which has two radioactive isotopes, but it also has stable isotopes.
4. N = 100 corresponds to fermium (Fm), which is a synthetic element and is highly radioactive.
So, the atomic number that represents a radioactive element is N = 100.
Therefore, the correct answer is option 4: N = 100.
The probable question may be:
Which of the following atomic numbers represent an element that is radioactive on the periodic table.
1. N=11
2.N=56
3.N=81
4.N=100