When a 30.98-g sample of phosphorus reacts with oxygen, a 71.00-g sample of phosphorus oxide is formed. What is the percent composition of the compound? What is the empirical formula for this compound?

1. A B. Theory is a framework of ideas and assumptions that has been well tested and can be used to explain some set of observations and make predictions about the world.

Although "theory" is a concept that is always in discussion, the scientifics agree on some points. It must be logically composed of concepts, definitions, assumptions, and generalizations. Secondly, it's major function is to describe and explain, it is important to say that a theory is a general explanation that leads to basic principles. In the third place, a theory is heuristic because it stimulates and guides to further development of knowledge.

2. How can astronomers locate objects in the sky?

D. by using the celestial sphere and constellations

Astronomers locate objects in the sky in a very simillar way we locate places in a map. Instead of using latitude and longitude, they use declination and right ascension. This is based on the celestial sphere, an imaginary object that is created by asuming all objects in space are at the same distance. By doing this astronomers can determine a line of zero latitude and zero longitude and therefore locate precisely distant objects. They can use also constelations as references with this same method.

The technique of thin-layer chromatography is used to compare ink on a suspect document. This is done by creating a chromatogram through exposing the ink to a solvent and observing the resulting pattern of spots.

The technique used to compare ink on a suspect document is A) thin-layer chromatography. Thin-layer chromatography is a type of chromatography that is widely used to separate mixtures in forensic analysis. In this process, the ink sample from the suspect document is placed on a thin layer of absorbent material.

The sample is then exposed to a solvent, which moves up the stationary phase, carrying different components of the ink at different rates. This results in a series of spots, that form a chromatogram, can then be compared to known samples for identification.

https://brainly.com/question/36127741

#SPJ12

Answer: Moles of strontium and nitrate ions formed by dissolving 0.5 moles of strontium nitrate in water are 0.5 moles and 1 mole respectively.

Explanation:

We are given a chemical compound known as strontium nitrate having chemical formula [tex]Sr(NO_3)_2[/tex]. This is an ionic compound and when it is dissolved in water, it will dissociate into its respective ions.

We are given:

Moles of strontium nitrate = 0.5 moles

The chemical equation for the ionization of strontium nitrate follows:

[tex]Sr(NO_3)_2(aq.)\rightarrow Sr^{2+}(aq.)+2NO_3^-(aq.)[/tex]

By Stoichiometry of reaction:

1 mole of strontium nitrate produces 1 mole of strontium ions and 2 moles of nitrate ions.

So, 0.5 moles of strontium nitrate will produce = [tex](1\times 0.5)=0.5mol[/tex] of strontium ions and [tex](2\times 0.5)=1mol[/tex] of nitrate ions.

Hence, moles of strontium and nitrate ions formed by dissolving 0.5 moles of strontium nitrate in water are 0.5 moles and 1 mole respectively.

Answer is: 180 mL of 7% vinegar and 60 mL of 11% vinegar.

ω₁ = 7% ÷ 100% = 0.07.
ω₂ = 11% ÷ 100% = 0.11.
ω₃ = 8% ÷ 100% = 0.08.
V₁ = ?.

V₂ = ?.
V₃ = V₁ + V₂.
V₃ = 240 mL.

V₁ = 240 mL - V₂.
ω₁ · V₁ + ω₂ ·V₂ = ω₃ · V₃.

0.07 · (240 mL - V₂) + 0.11 · V₂ = 0.08 · 240 mL.

16.8 mL - 0.07V₂ + 0.11V₂ = 19.2 mL.

0.04V₂ = 2.4 mL.

V₂ = 2.4 mL ÷ 0.04.

V₂ = 60 mL.

V₁ = 240 mL - 60 mL.

V₁ = 180 mL.

Answer: t = d/s , s= d/t d= st

Explanation:

I did the assignment (Also Ikix don´t take this down again)

The correct variations of the speed formula are d = st, representing the calculation of distance, and t = d/s, representing the calculation of time. The options s = t and s = dt don't seem to be valid variations of the speed formula.

The formula for speed is typically represented as s = d/t, where s is speed, d is distance, and t is time. The variations of this formula would then be d = st, which gives us the distance traveled if we know the speed and time, and t = d/s, which gives us the time taken if we know the distance and speed. These variations are crucial in different parts of physics, primarily when dealing with motion-related problems.

In the question, the terms d = st and t = d/s are correct variations, while s = t and s = dt don't seem to be valid in the context of speed formula. In speed calculations, it's always important to remember units of measurement, as speed could be recorded in terms such as miles per hour or meters per second, depending upon the context.

https://brainly.com/question/16242493

#SPJ2

Explanation:

The mass number of an element is a weighted average of all the isotopes of that element.

If Au has only one isotope then the atomic weight of that isotope matches the mass number.

Au-197 ==> mass number 197

Mass of one atom=mass number 197 amu

Mass of one mol of atoms:

[tex]m=197 amu*1.66054*10^{-24}g/amu*6.022*10^{23}[/tex]

[tex]m=196.97 g[/tex]

Answer: wait im gonna search some info.

Explanation:I come back with an asnwer for you

The calcium chloride needed to produce 1.5 grams of KCl is: 1.12 grams

Stoichiometry in Chemistry learn about chemicals mainly emphasizes quantitative, such as the calculation of volume, mass, number, which is related to numbers, molecules, elements, etc.

A reaction coefficient is a number in the chemical formula of a substance involved in the reaction equation. The reaction coefficient is useful for equalizing reagents and products.

In the reaction there are also manifestations of reagent substances namely gas (g), liquid (liquid / l), solid (solid / s) and solution (aqueous / aq).

Reactions that occur:

CaCl₂ (aq) + K₂CO₃ (aq) → 2 KCl (aq) + CaCO₃ (aq)

From the reaction equation above, the reaction coefficient shows the mole ratio of reagents and products

mol CaCl₂: moles of KCl = 1: 2

relative molecular mass KCl = 74.6

relative molecular mass of CaCl2 = 111

then the mole:

mole KCl = mass: relative molecular mass

mole KCl = 1.5 gram: 74.6

mole KCl = 0.020107

so that

mole CaCl₂ = 1/2. 0.020107

mole CaCl₂ = 0.0100535

So the mass of CaCl2 = mole x relative molecular mass

mass CaCl₂ = 0.0100535 x 111

mass CaCl₂ = 1.12 gram

moles of water

https://brainly.com/question/1405182

grams of oxygen required

https://brainly.com/question/8175791

mass of copper required

https://brainly.com/question/1680090

Keywords: CaCl2, KCl, mole, mass, relative molecular mass

The mass calcium chloride needed is 1.12 g

The balanced equation for the reaction is illustrated below:

CaCl₂ + K₂CO₃ —> 2KCl + CaCO₃

Next, we shall determine the mass of CaCl₂ that reacted and the mass of KCl produced from the balanced equation.

Molar mass of CaCl₂ = 40 + (35.5×2)

= 40 + 71

= 111 g/mol

Mass of CaCl₂ from the balanced equation = 1 × 111 = 111 g

Molar mass of KCl = 39 + 35.5

= 74.5 g/mol

Mass of KCl from the balanced equation = 2 × 74.5 = 149 g

Thus,

From the balanced equation above,

111 g of CaCl₂ reacted to produce 149 g of KCl.

Finally, we shall determine the mass of CaCl₂ needed to produce 1.5 g of KCl as follow:

From the balanced equation above,

111 g of CaCl₂ reacted to produce 149 g of KCl.

Therefore, X g of CaCl₂ will react to produce 1.5 g of KCl i.e

Thus, 1.12 g of calcium chloride, CaCl₂ is needed to produce 1.5 g of KCl.

Learn more: https://brainly.com/question/13143779

Answer:

C. The rocket might explode from the added pressure when combustion reaction hits the air pocket.

Explanation:

Correct answer for *APEX quiz!

The rocket might explode from the added pressure when combustion reaction hits the air pocket. Hence, option C is correct.

Combustion is another word for burning. In a combustion reaction, a fuel is heated and it reacts with oxygen.

In a rocket engine , fuel and a source of oxygen, called an oxidizer, are mixed and exploded in a combustion chamber.

The combustion produces hot exhaust which is passed through a nozzle to accelerate the flow and produce thrust.

Hence, option C is correct.

Learn more about the combustion here:

https://brainly.com/question/14521417

#SPJ2

Answer:

one S four O atoms

Explanation:

To produce 50.0 g of calcium oxide, 89.29 g of calcium carbonate is required. The amount is calculated based on the fixed ratio of the decomposition reaction of calcium carbonate, which aligns with the law of conservation of mass.

To determine the mass of calcium carbonate ([tex]CaCO_3[/tex]) needed to produce 50.0 g of calcium oxide (CaO), it's essential to refer to the stoichiometry of the chemical reaction. The balanced chemical equation for the decomposition of calcium carbonate is:

From the given examples, we can deduce that when 10.0 g of calcium carbonate decompose, they produce 5.6 g of calcium oxide. This means there is a fixed ratio of mass of calcium carbonate to calcium oxide, which is:

To produce 50.0 g of calcium oxide, we can set up a proportion based on the fixed ratio:

By solving for x, which represents the mass of calcium carbonate needed, we can cross-multiply and divide to find the answer:

x = 89.29 g of CaCO3

Therefore, to obtain 50.0 g of calcium oxide, you would need 89.29 g of calcium carbonate. This calculation is in agreement with the law of conservation of mass, which states that mass is neither created nor destroyed in a chemical reaction.

Answer: The correct answer is C) 3.33 grams

Explanation: 1/8 of the initial 10 grams is a little more than 1 gram, while 1/16 of 10 grams is a little more than 1/2 gram. The only answer that falls in that range is 1.00 gram. Use the integrated rate equation: ln(g0/gt) = kt, also ln(2) = kt1/2. Therefore k = (0.693)/36 min = 0.0193 min-1. In addition to the specific chemical properties that distinguish different chemical classifications, chemicals can exist in several phases. For the most part, the chemical classifications are independent of these bulk phase classifications; however, some more exotic phases are incompatible with certain chemical properties. A phase is a set of states of a chemical system that have similar bulk structural properties, over a range of conditions, such as pressure or temperature. Physical properties, such as density and refractive index tend to fall within values characteristic of the phase. The phase of matter is defined by the phase transition, which is when energy put into or taken out of the system goes into rearranging the structure of the system, instead of changing the bulk conditions.

Sometimes the distinction between phases can be continuous instead of having a discrete boundary' in this case the matter is considered to be in a supercritical state. When three states meet based on the conditions, it is known as a triple point and since this is invariant, it is a convenient way to define a set of conditions.

The most familiar examples of phases are solids, liquids, and gases. Many substances exhibit multiple solid phases. For example, there are three phases of solid iron (alpha, gamma, and delta) that vary based on temperature and pressure. A principal difference between solid phases is the crystal structure, or arrangement, of the atoms. Another phase commonly encountered in the study of chemistry is the aqueous phase, which is the state of substances dissolved in aqueous solution (that is, in water).

After observations are made, it is crucial to record and present results properly, discuss findings, and formulate hypotheses for further testing in the scientific investigation process.

After measurements or observations are made in a scientific investigation, it's most appropriate to record your observations and present your results in a suitable format, such as tables and graphs. Discussing findings with group members is also important, coupled with formulating a relevant central idea. If a scientist develops a new idea based on their observations of nature, the next step would be to make a new hypothesis, which can then be tested through experiments.

As part of the scientific method, it's essential not to force data to fit a hypothesis. Instead, draw conclusions from the experiment results objectively. If data fits, you should repeat the experiment to verify results, or if it does not, conduct more background research and refine the hypothesis.

Final answer:

The Tacoma Narrows Bridge collapsed due to resonance caused by heavy crosswinds and insufficient damping. The bridge's design did not consider these factors, leading to its failure.

Explanation:

The catastrophic collapse of the Tacoma Narrows Bridge stands as a poignant reminder of the critical importance of comprehensive engineering considerations. The unfortunate event was precipitated by intense crosswinds that triggered resonant oscillations within the bridge, ultimately leading to its demise. The absence of sufficient damping, exacerbated by the detachment of support cables, allowed the oscillations to escalate uncontrollably, reaching destructive amplitudes.

The failure highlighted a critical oversight in the bridge's design, as it did not incorporate adequate measures to mitigate the effects of resonance. The omission of sophisticated mathematical tools for analyzing wave dynamics and resonance in structural engineering further underscored the limitations in understanding and predicting the complex interplay of forces. This incident spurred advancements in engineering practices, emphasizing the imperative of incorporating resonance considerations and meticulous mathematical modeling to enhance the structural integrity and resilience of bridges and similar constructions. The lessons learned from the Tacoma Narrows Bridge collapse have significantly influenced subsequent infrastructure projects, contributing to the evolution of engineering practices and the development of more robust and secure structures.

To calculate temperature of a gas, use the ideal gas law PV=nRT. Substitute the given values, including the number of moles calculated from the mass and molar mass of chlorine, and solve for the temperature. The result will be in Kelvin, so convert to Celsius.

The celsius temperature of 100.0 g of chlorine gas in a 55.0-l container at 800 mm hg can be calculated by using the ideal gas law: PV = nRT. Here, P = Pressure = 800 mm hg (we must convert this to atmospheres by using the conversion factor 1 atm = 760 mm hg), V = volume = 55.0 liters, n = number of moles (which we can calculate by using chlorine's molar mass), R = ideal gas constant = 0.08206 L.atm/(mol.K), T = temperature (which is what we're solving for). After substitifying and calculating values, the final temperature would be expressed in Kelvin, which could be easily converted to Celsius by subtracting 273.15.

https://brainly.com/question/30458409

#SPJ3

Answer: 0.0612 kcalories

Explanation:

Endothermic processes are those processes in which heat is absorbed and exothermic processes are those processes in which heat is released.

Standard units for heat measurement are Joules and calories wherein

1 joule = 0.239 calorie.

As 1 Joule is equivalent to 0.239 calorie

256 Joules are equivalent to=[tex]\frac{0.239}{1}\times 256=61.2calories[/tex]

Now 1 cal = 0.001 kcalories

Therefore 61.2 calories=[tex]\frac{0.001}{1}\times 61.2=0.0612kcal[/tex]

Answer:

dipole-dipole

Explanation:

Polar molecules are formed as result of covalent bonds between atoms.

Dipole-dipole attraction are intermolecular bonds. Both London dispersion forces and dipole-dipole attraction are van der waals forces.

In dipole-dipole attraction, polar molecules (unsymmetrical molecules) line up such that the positive pole of one molecule attracts the negative pole of another. Example of such is found in HCl.

Answer:

Dipole-dipole forces are the van der Waals forces that hold polar molecules together!!

Answer: The reaction can take place only if energy is added.

Explanation:

Exothermic processes are those processes in which heat is released and endothermic processes are those processes in which heat is absorbed.

Photosynthesis is a phenomenon in which green plants containing chlorophyll use sunlight as a source of energy to convert carbon dioxide and water to form glucose and oxygen.

Photosynthesis is the process used by plants, algae and certain bacteria to convert energy from sunlight and turn it into chemical energy in the form of glucose which is used a s a source of energy by many organisms.

[tex]6CO_2+6H_2O\overset{sunlight}\rightarrow C_6H_{12}O_6+6O_2[/tex]

Thus photosyynthesis reaction can take place only if energy is added.

Final answer:

To determine the volume of NO gas produced from 854 L of NO₂ gas reacting with water, the stoichiometry of the balanced reaction (3 NO₂(g) + H₂O(l) → 2 HNO₃(aq) + NO(g)) indicates a 3:1 ratio. Using this ratio, the calculated volume of NO gas produced is 284.67 L.

Explanation:

To calculate the volume of NO gas produced when 854 L of NO₂ gas react with water, we can use the stoichiometry of the balanced chemical equation:

3 NO₂(g) + H₂O(l) → 2 HNO₃(aq) + NO(g)

According to the equation, 3 moles of NO₂ produce 1 mole of NO. This ratio can be applied to the volumes of the gases involved, as they are both measured under the same conditions and thus follow the ideal gas law where volume is directly proportional to moles.

To find the volume of NO produced:

Determine the mole ratio from the chemical equation: 3 moles of NO₂ produce 1 mole of NO.

Use the mole ratio to find the volume ratio for NO₂ to NO, which is also 3:1.

Apply the volume ratio to the given volume of NO₂: 854 L of NO₂ × (1 mole NO / 3 moles NO₂) = 284.67 L of NO.

So, under the same conditions, the volume of NO gas produced would be 284.67 L.

Answer:The correct answer is option b.

Explanation:

[tex]HA+H_2O\rightleftharpoons A^-+H_20^+[/tex]

The equilibrium constant expression is given as:

[tex]K_{eq}=\frac{[A^-][H_3O^+]}{[HA][H_2O]}[/tex]

[tex]K_a=K_{eq}\times [H_2O]=\frac{[A^-][H_3O^+]}{[HA]}[/tex]

The acid dissociation constant is product of equilibrium constant and concentration of water.

Hence,from the given options the correct answer is option b.

The molecule CH3CH2CCH has a Lewis structure of H3C-CH2-C≡CH. It contains 11 sigma bonds and 2 pi bonds, which represent the different forms of covalent bonds due to the overlap of atomic orbitals.

The molecule CH3CH2CCH, also known as 1-Butyne, is composed of hydrogen (H) and carbon (C) atoms. Its Lewis structure can be represented as:

H3C-CH2-C≡CH.

Here, each line represents a bond between two atoms, which could be a sigma (σ) or a pi (π) bond. In the case of CH3CH2CCH, there are a total of 11 sigma bonds. You can see these as the bonds between H and C in the CH3 and CH2 groups, the single bond between the two C atoms in the center, and the bond between the last C and H atoms. As for the pi bonds, represented by two lines (double/triple bonds), there are 2, which can be seen in the triple bond of C≡C.

Sigma bonds represent the overlap of atomic orbitals to form a covalent bond, with the electron density concentrated along the internuclear axis. Conversely, pi bonds occur due to the side-by-side overlap of atomic orbitals where the electron density is concentrated on two parallel lines.

https://brainly.com/question/7368103

#SPJ5

Answer:

yeah...what he/she said...lol

Explanation: I was going to say that anyways.....btw am i the only one who has a problem with chemistry right now??? I need a tutor right about now....like baddddd!!!!