John daltons atomic theory is considered to be the first truly scientific theory of the atom. What aspect of daltons research was missing from the early theories?
A) experimentation and examination of the results
B) Effective technology in the form of microscopes
C) appropriate mathematical formulas for testing
D) a community of scientist capable of reviewing his work
Answer:
A) experimentation and examination of the results
Explanation:
From a historical and philosophical point of view, Dalton is considered the father of atomic theories. For over 20 centuries no one has manipulated the concept of atom. He had the audacity and the courage to manipulate these theories to try to explain what atoms would be by experimenting and analyzing the results.
For Dalton, matter was discontinuous, that is, between the atoms that compose it there would be empty spaces. Although considered theoretic behind the proposition of this model, Dalton considered relevant information from other studies (Proust's weighted laws; Lavoisier and the element conception; gases and their laws etc.), which allowed his model to explain the phenomena even then discussed. This is the "asset" of his atomic model, for though it presents clear constraints on today's science, for his contemporaries, this model satisfied many behaviors that continuous matter was unable to even predict.
Dalton's ideas were considered appropriate because of his effort to link theoretical postulates with scientifically obtained data through experimentation. This fact corroborated the acceptance of his model by the scientists of the time, making Dalton enter the history of chemistry and humanity.
if mass =180kg and volume =90m3, what is the density
Which of the solutions below have the same molar concentration as solution x? check all that apply?
How can the match remain unlit in the middle of the flame of a brusen burner
Answer:
By leaving the air valve almost close, so the flow of oxygen is as low as the combustion is not carried out properly, therefore, the flame will not rise beyond the middle of the ideally whole flame.
Explanation:
Hello,
On the attached picture, you will find a scheme showing the flame behavior of a bunsen burner in which it is seen that the middle of the flame matches with the hottest temperature due to the complete combustion of the fuel. It is possible for the match to remain unlit in the middle of the whole flame if the airflow is as low as the combustion is not carried out properly as shown below the middle of the flame; it implies that the feed of oxygen is low so its valve remains almost closed.
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examine Na+ with the anions F-, Br-, OH-, NO3-, and ClO4-. How many anions are there in each of these formulas?
The formulas for the anions NaF, NaBr, NaOH, NaNO3, and NaClO4 have only one anion present in each formula.
Explanation:The given question asks to examine Na+ with different anions and determine the number of anions present in each formula.
Na+ is a cation with a +1 charge. The anions mentioned in the question are F-, Br-, OH-, NO3-, and ClO4-. The formulas for these anions are NaF, NaBr, NaOH, NaNO3, and NaClO4, respectively.
In each of these formulas, there is only one anion present, which is indicated by the negative charge in the formula. Therefore, the number of anions in each formula is 1.
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Draw the electron configuration for a neutral atom of calcium
In order to write the Calcium electron configuration we first need to know the number of electrons for the Ca atom (there are 20 electrons). When we write the configuration we'll put all 20 electrons in orbitals around the nucleus of the Calcium atom.
In writing the electron configuration for Calcium the first two electrons will go in the 1s orbital. Since 1s can only hold two electrons the next 2 electrons for Calcium go in the 2s orbital. The next six electrons will go in the 2p orbital. The p orbital can hold up to six electrons. We'll put six in the 2p orbital and then put the next two electrons in the 3s. Since the 3s if now full we'll move to the 3p where we'll place the next six electrons. We now shift to the 4s orbital where we place the remaining two electrons. Therefore the Calcium electron configuration will be 1s22s22p63s23p64s2.
The atomic number of calcium is 20. Then the electronic configuration of calcium is 1 s₂, 2 s₂, 2 p₆, 3 s₂, 3 p₆ 4 s₂ .
What is electronic configuration ?The distribution of electrons in an element's atomic orbitals is described by the element's electron configuration. Atomic electron configurations adhere to a standard nomenclature in which all atomic subshells that contain electrons are arranged in a sequence with the number of electrons they each hold expressed in superscript.
One orbital can house a maximum of two electrons, and there are four different types of orbitals (s, p, d, and f). More electrons can be held in the p, d, and f orbitals since they contain various sublevels.
Consequently, the electron configuration of calcium will be 1s22s22p63s23p64s2. The configuration notation gives scientists a simple way to express and record how electrons are organized around an atom's nucleus. As a result, it is simpler to comprehend and forecast how atoms will interact to produce solids.
Thus, the electronic configuration of calcium is 1 s₂, 2 s₂, 2 p₆, 3 s₂, 3 p₆ 4 s₂ .
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How many water molecules are in a block of ice containing 1.75 mol of water (H2O)?
Answer: The number of molecules present in the given moles of water are [tex]1.054\times 10^{24}[/tex]
Explanation:
We are given:
Moles of water = 1.75 moles
According to mole concept:
1 mole of a compound contains [tex]6.022\times 10^{23}[/tex] number of molecules.
So, 1.75 moles of water will contain = [tex]1.75\times 6.022\times 10^{23}=1.054\times 10^{24}[/tex] number of molecules.
Hence, the number of molecules present in the given moles of water are [tex]1.054\times 10^{24}[/tex]
how many protons electrons and neutrons does the isotope nitrogen 15 have
Nitrogen-15 (^(15)N) has 7 protons, 7 electrons, and 8 neutrons. The atomic number (protons) is 7, and the mass number (protons + neutrons) is 15.
Nitrogen-15 (^(15)N) is an isotope of nitrogen, and it has a specific composition of protons, electrons, and neutrons.
1. Protons (atomic number): Nitrogen-15 has 7 protons. The atomic number of an element defines its identity and determines the number of protons in its nucleus. In the case of nitrogen, regardless of the isotope, it always has 7 protons.
2. Electrons: Since nitrogen-15 is an electrically neutral atom (it has no charge), it has an equal number of electrons as protons. Therefore, it also has 7 electrons. Electrons orbit the nucleus in energy levels or shells, and they play a crucial role in chemical bonding and reactivity.
3. Neutrons: Nitrogen-15 has 8 neutrons. Neutrons are electrically neutral subatomic particles found in the nucleus of an atom. They contribute to the atom's mass but not its charge. To determine the number of neutrons in an isotope, you subtract the atomic number (protons) from the mass number. In this case, 15 (mass number) - 7 (protons) = 8 neutrons.
Understanding the composition of isotopes, like nitrogen-15, is essential in chemistry and nuclear physics. It helps in differentiating between various forms of an element based on their nuclear properties. Nitrogen-15 is one of the stable isotopes of nitrogen, commonly used in scientific research, including nuclear magnetic resonance (NMR) spectroscopy and tracer studies in biology and chemistry.
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The simplest unit of matter that still retains the properties of an element is a(n) _____.
How can an unsaturated solution of a solid Be made saturated?
Answer:
Adding more solid.
Explanation:
Hello,
Based on the concern, it is known that an unsaturated solution is made when one adds an amount of the solid that is smaller than its solubility for the given amount of solute at the specified temperature, thus, to make a saturated solution, more solute must be added in order for it to equal the solubility at the very same amount of the solvent and at the same specified temperature.
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Question 15 there are three sets of sketches below, showing the same pure molecular compound (hydrogen chloride, molecular formula hcl ) at three different temperatures.
What could you do to change the volume of gas
7 seres vivos ejemplo
A sulfur atom and a sulfur molecule are not identical. what is the difference?
How many molecules of ethanol (c2h5oh) (the alcohol in alcoholic beverages) are present in 155 ml of ethanol? the density of ethanol is 0.789 g/cm3?
First convert volume to mass:
mass = 0.789 g/mL * 155 mL = 122.295 g
Then convert mass to number of moles:
number of moles = 122.295 g * (1 mole / 46 g) = 2.66 moles
Using avogadros number, we get the molecules:
number of molecules = 2.66 moles * 6.022 x 10^23 molecules / mole = 1.6 x 10^24 molecules
How many grams of Cl are in 525g of CaCl2
First we determine the moles CaCl2 present:
525g / (110.9g/mole) = 4.73 moles CaCl2 present
Based on stoichiometry,
there are 2 moles of Cl for every mole of CaCl2:
(2moles Cl / 1mole CaCl2) x 4.73 moles CaCl2 = 9.47 moles Cl
Get the mass:
9.47moles Cl x 35.45g/mole = 335.64 g Cl
What is the automatic number of a sodium atom that has 11 protons and 12 neutrons
determain the molecular mass of T2 ^17O2. Explain answer to me because I have a lot of questions like this
How many moles of o2- ions are there in 0.350 moles of aluminum oxide, al2o3?
There are 1.05 moles of O²⁻ in 0.350 moles of Al₂O₃.
FURTHER EXPLANATION The chemical formula of a compound consists of the chemical symbol of the elements that make up the compound and a small number written to the right of the symbol or the subscript. The subscript indicates how many atoms or ions of that element is found in one unit (formula unit or molecule) of the compound. It also indicates how many moles of the atom or ion are present in one mole of the compound. Example, the chemical formula of calcium chloride is CaCl₂. This can be interpreted in two ways:1) There is one Ca²⁺ and and two Cl⁻ in one formula
unit of calcium chloride.
2)There is one mole of Ca²⁺ and and two moles of Cl⁻ in
one mole of calcium chloride.
It is important to remember that the mole concept considers particles in bundles (or sacks) with one mole being one bundle (or sack) which consists of 6.022 ×10²³ particles. This number is called Avogadro's number. The particles may be atoms, ions, molecules, or formula units.The compound in the problem is Al₂O₃. Similar to the example, this chemical formula can be interpreted in two ways:
There are 2 aluminum ions (Al³⁺) and 3 oxide ions (O²⁻) in one formula unit of Al₂O₃.There are 2 moles of aluminum ions (Al³⁺) and 3 moles of oxide ions (O²⁻) in one mole of Al₂O₃.To determine how many moles of O²⁻ are in 0.350 moles of Al₂O₃, the equation below may be used:
[tex]moles \ of \ O^{2-} = 0.350 \ mol \ Al_2O_3 \times \frac{3 \ mol \ O^{2-}}{1 \ mol \ Al_2O_3}\\\\\boxed {\boxed {moles \ of \ O^{2-} = 1.05 \ mol \ O^{2-}}}[/tex]
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Keywords: moles, mole ratio
Hardness is related to:
specific gravity
surface roughness
size of the sample
strength of chemical bonds
Answer: Option (d) is the correct answer.
Explanation:
When atoms of a substance are strongly held together due to strong intermolecular forces of attraction then the substance acquires a fixed shape and volume.
Hence, the substance becomes hard in nature.
For example, solids are hard in nature due to the strength of chemical bonds between its atoms which are held by strong intermolecular forces of attraction.
Whereas in liquids, molecules are held by less strong intermolecular forces of attraction. As a result, they do not have fixed shape and volume.
Thus, we can conclude that hardness is related to strength of chemical bonds.
if you want to test whether a rock has calcite in it you could use the ?
"what is the probability of finding an electron within one bohr radius of the nucleus"
Ethanol is a common laboratory solvent and has a density of 0.789 g/mL. What is the mass, in grams, of 113 mL of ethanol?
Answer: The mass of ethanol is 89.2 grams
Explanation:
Density is defined as the mass contained per unit volume.
[tex]Density=\frac{mass}{Volume}[/tex]
Given : Mass of ethanol = ?
Volume of ethanol = 113 ml
Density of ethanol = 0.789 g/ml
Putting in the values we get:
[tex]0.789g/ml=\frac{mass}{113ml}[/tex]
[tex]mass=89.2g[/tex]
Thus mass of ethanol is 89.2 grams
Ethanol is a common laboratory solvent and has a density of 0.789 g/mL. The mass, in grams, of 113 mL of ethanol is 89.217 g.
Solvent is a part of solution in which solute is dissolved to form a solution.
To find the mass, we can use the formula:
mass = volume [tex]\times[/tex] density
where the volume is given as 113 mL and the density is given as 0.789 g/mL.
mass = 113 ml [tex]\times[/tex] 0.789 g/mL = 89.217 g
Therefore, the mass of 113 mL of ethanol is 89.217 g.
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Calculate how much 95% ethyl alcohol will be required to dissolve 0.1 g of sulfanilamide at 78 c using volume calculate how much sulfanilamide will remain dissolved after mixture is cooled to 0
This question involves calculating the volume of 95% ethyl alcohol needed to dissolve 0.1 g of sulfanilamide at 78°C and the remaining amount dissolved at 0°C, but these calculations depend on the solubility information of sulfanilamide in ethyl alcohol at these temperatures.
Explanation:To calculate how much 95% ethyl alcohol is required to dissolve 0.1 g of sulfanilamide at 78°C, you would need to know the solubility of sulfanilamide in the alcohol at that temperature. Without this information, an accurate calculation cannot be made. However, once that solubility information is available, you could use the definition of percent yield (the mass of the solute divided by the solvent volume multiplied by 100) to calculate the amount of alcohol needed.
Similarly, to calculate how much sulfanilamide will remain dissolved when the mixture is cooled to 0°C, you would need the solubility of sulfanilamide in ethyl alcohol at 0°C. This is because solubility can change dramatically with temperature.
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Calculate the volume of 95% Ethyl Alcohol needed to dissolve 0.1 g sulfanilamide at 78°C (result: 0.476 mL), and then determine how much will remain dissolved when cooled to 0°C (result: 0.006664 g).
A. To calculate this:
Determine the solubility at the given temperature (0.210 g/mL).
Calculate the required volume of solvent:
Volume = mass / solubility = 0.1 g / 0.210 g/mL ≈ 0.476 mL
B. To calculate this:
Determine the solubility at 0°C (0.014 g/mL).
Calculate the amount of sulfanilamide that remains dissolved in 0.476 mL of solvent:
Remaining dissolved = volume x solubility = 0.476 mL x 0.014 g/mL ≈ 0.006664 g
Complete question:
A) Calculate how much 95% Ethyl Alcohol will be required to dissolve 0.1 g sulfanilamide at 78 C. (At 80 C, solubility = 210 mg/mL)
B) Using the volume of solvent calculated in Step 1, calculate how much sulfanilamide will remain dissolved in the mother liquid after the mixture is cooled to ) C. (At 0 C, solubility = 14 mg/mL)
How many h2o molecules are in a 9.00-g sample of water?
How do scientists determine the number of neutrons in an atom?
Question 4 options:
They subtract the atomic number from the atomic mass.
They add the number of electrons and protons.
They find the number of protons.
They divide the atomic mass by two.
Calculate the molarity of 0.850 mol of Na2S in 1.70 L of solution.
Molarity is simply the ratio of the number of moles of a substance over the total volume of the solution. Assuming that the addition of 0.850 moles does not change the overall volume of 1.70 L, therefore molarity is simply:
Molarity = 0.850 moles / 1.70 L = 0.5 moles / L = 0.5 M
The molarity of 0.850 mol of Na2S in 1.70 L of solution is calculated to be 0.50 M.
Explanation:The subject of your question revolves around the calculation of molarity, which in chemistry represents the concentration of a solute in a solution. To calculate molarity, we need to divide the number of moles of the solute by the volume of the solution in liters. The formula is M = moles/volume. For your specific question, you want to calculate the molarity of 0.850 mol of Na2S in 1.70 L of solution. Using the formula, the calculation becomes: M = 0.850 mol / 1.70 L = 0.50 M.
For this specific scenario, where we have 0.850 moles of Na2S in a 1.70 L solution, the molarity (M) is determined by the formula M = moles/volume, resulting in a molarity of 0.50 M. This calculation allows us to precisely quantify the concentration of the solute in the given solution, a fundamental aspect of chemical analysis and reactions.
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A 6.50x10^-5 m solution of potassium permanganate has a percent transmittance of 27.3% when measured in a 1.15 cm cell at a wavelength of 525 nm. calculate the absorbance of this solution
how many grams of mercury are present in a barometer that holds 6.5 ml of mercury
When 56 J of heat are added to 11 g of a liquid, its temperature rises from 10.1 ∘C to 13.5 ∘C
To calculate how much the temperature of a substance will increase when a certain amount of heat is added, you can use the formula q = mcΔT, where q is the heat added, m is the mass, c is the specific heat capacity, and ΔT is the change in temperature. For question 6, the final temperature of mercury after adding 195 cal of heat can be calculated using the specific heat capacity of mercury. For question 7, the mass of copper can be determined using the heat absorbed and the temperature change. For question 8, the mass of the NaCl crystal can be calculated using the same principles.
Heat transfer calculations require knowledge of the specific heat capacity of the substance in question, which varies for different materials. This capacity indicates how much heat is needed to raise the temperature of one gram of the substance by one degree Celsius. In the questions provided, using the formula and the known quantities, you can rearrange the formula to solve for the unknown variable such as the final temperature, mass, or heat added based on specific heat capacity values.