Which of the following is a scientific question you could ask about shoes?
A. Are modern sandals similar to sandals from the 1960s?
B. What shoes will be popular next summer?
C. What is my favorite shoe color?
D. Are there any running shoes that help people run faster?

Answer:

1. Rutherford did the scattering experiment and observed that some of the rays bounce back. He concluded that there is a mass in which positive charge is concentrated. This marks the discovery of nucleus.

2. J.J Thomson discovered electrons by conducting cathode ray experiment.

3. Dalton postulated that matter is made up of small particles caled atoms

The spontaneity of a reaction is determined by the Gibbs free energy change (∆G), which is a measure of the system's ability to do work.

The equation that links ∆G, ∆H, and ∆S is: ∆G = ∆H - T∆S, where T is the temperature in Kelvin and ∆H and ∆S are the enthalpy and entropy changes, respectively. The signs of ∆H and ∆S determine whether the reaction is exothermic or endothermic and whether it is entropy-driven or enthalpy-driven, respectively.

If ∆G is negative, the reaction is spontaneous, meaning it occurs without the input of energy.The given reaction has a ∆H of 23.25 kJ and a ∆S of 161.26 J/mol∙K.

First, we need to convert the units of ∆S from J/mol∙K to kJ/mol∙K by dividing by 1000.∆S = 161.26 J/mol∙K ÷ 1000 = 0.16126 kJ/mol∙K Substitute the values into the equation to determine the spontaneity of the reaction:

∆G = ∆H - T∆S∆G = (23.25 kJ) - (298 K) x (0.16126 kJ/mol∙K)∆G = 23.25 kJ - 48.02 kJ∆G = -24.77 kJ Since ∆G is negative, the reaction is spontaneous.

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Astrobiologist means someone who studies the possibilities of life beyond earth. what would YOU do to search for life? They're asking for your opinion :)

ANSWER

Option C

EXPLANATION

Given that;

In the reaction above, we have the following data

At the reactants side;

3 atoms of manganese

4 atoms of nitrogen

1 atom of sodium

1 atom of fluorine

At the products side

1 atom of manganese

4 atoms of fluorine

3 atoms of sodium

1 atom of nitrogen

To balance the above equation, apply the law of conservation mass

Law of conservation of mass states that matter can neither be created nor destroyed but can e transformed from one formato another.

To balance the equation, 1 mole of Mn3N4 reacts with 12 moles of Na Tto give 3 moles of MnF4 and 4 moles of Na3N

So, the new equation becomes

The following data can be deduced in the above equation

At the reactants side

3 atoms of Mn

4 atoms of N

12 atoms of Na

12 atoms of F

At the products side

3 atoms of Mn

12 atoms of F

12 atoms of Na

4 atoms of N

Looking atthe vabove data, the number of atoms of each element at the reactants side is equal to the number of atoms of same elements at the products side.

Hence, the correct answer is option Ce

u

Answer:

B. with more motion of particles within a substance.

Answer:

B. with more motion of particles within a substance.

Hope this helps!

The partial pressure of oxygen in his lungs will be 108 kPa.

The correct option is C.

The partial pressure of oxygen is 21.39 kPa. The correct option is B.

The number of moles of oxygen that you take in is 4.845 moles.

The pressure of oxygen in the lungs of the diver is calculated below:

The Pressure of oxygen = 21 % * 512 kPa

The Pressure of oxygen = 108 kPa.

The partial pressure of oxygen = Total pressure -  partial pressure of water vapor

The partial pressure of oxygen = 22 kPa - 0.61 kPa

The partial pressure of oxygen = 21.39 kPa

The number of moles of oxygen taken in, n = PV/RT

n = 1000 * 12 / 8.31 * 298

n = 4.845 moles

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Answer:

108 kPa.

Explanation:

Answer: C

Explanation: Based on the periodic table, O is atomic number 8, which means it has 8 electrons. The first few atomic orbitals are 1s, 2s, and 2p.Each orbital can hold 2 electrons maximum, and there are 2l+1 of each type of orbital (s,p,d,f,g,...), where l=0 corresponds to an s orbital, l=1 means porbital, and so on. So, the configuration for neutral O atom is: 1s22s22p4. When oxygen gains two electrons, it acquires a charge of 2−. Therefore, the twoelectrons, which go into the highest-energy atomic orbitals, give you a new configuration of1s22s22p6for O2−, which is the same electron configuration as Ne. That is known as a noble-gas-like configuration, and in general it is stable if oxygen is like that in a compound (having 8 electrons in its 2s and 2p orbitals combined).

Nitrogen returns to the atmosphere through a process called denitrification.

This process is a vital component of the nitrogen cycle, which consists of several stages that ensure the circulation and transformation of nitrogen between the atmosphere, living organisms, and the environment. Here's a step-by-step explanation of how denitrification occurs:

1. Nitrogen fixation: Atmospheric nitrogen (N2) is converted into ammonia (NH3) by nitrogen-fixing bacteria or during natural processes like lightning. This makes nitrogen available for plants to use.

2. Nitrification: Ammonia is then converted into nitrites (NO2-) and nitrates (NO3-) by nitrifying bacteria. These are more accessible forms of nitrogen for plant absorption.

3. Assimilation: Plants absorb the nitrites and nitrates through their roots, incorporating the nitrogen into their cells for the production of proteins, DNA, and other essential molecules.

4. Ammonification: When plants and animals die, decomposer organisms break down their organic matter, releasing nitrogen in the form of ammonia back into the soil.

5. Denitrification: Finally, denitrifying bacteria convert nitrates and nitrites in the soil back into nitrogen gas (N2), which is released into the atmosphere, completing the nitrogen cycle.

Denitrification is an essential process that helps maintain the balance of nitrogen in the environment and ensures that it is available to support the growth and reproduction of plants and other living organisms.

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The mineral group that has silicon-oxygen tetrahedra bonded in a sheet structure is the silicates.

Silicates are a large group of minerals that contain the element silicon in various oxidation states, from (quartz) to (felspars and amphiboles). The tetrahedral bonding of silicon and oxygen in the silicate sheets gives these minerals their characteristic strength and stability. Silicates are one of the most abundant mineral groups on Earth and are found in a wide variety of rock formations, including igneous, sedimentary, and metamorphic rocks.  

The tetrahedral bonding of silicon and oxygen in the silicate sheets gives these minerals their characteristic strength and stability. Tetrahedral bonding occurs when four atoms share a central atom, in this case, silicon, with a covalent bond. The silicon atom is bonded to four oxygen atoms, which form a tetrahedral shape. This bonding arrangement gives the silicate sheets their strength and stability, making them one of the most common mineral groups on Earth.

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If you were to increase the concentration of reactants (SO₄²⁻ or HCN), the equilibrium would shift to the right, favoring the formation of products (HSO₄⁻ and CN⁻). Conversely, if you increased the concentration of products (HSO₄⁻ or CN⁻), the equilibrium would shift to the left, favoring the formation of reactants (SO₄²⁻ and HCN).

The reaction you provided is: SO₄²⁻(aq) + HCN(aq) → HSO₄⁻(aq) + CN⁻(aq)

To determine if this reaction is reactants favored or products favored, we need to know the equilibrium constant (K). However, this information is not provided.

Nevertheless, to predict the direction of the equilibrium shift, we can apply Le Chatelier's Principle. This principle states that if a system at equilibrium is subjected to a change in concentration, temperature, or pressure, the system will shift its equilibrium position to counteract the change.

So, if you were to increase the concentration of reactants (SO₄²⁻ or HCN), the equilibrium would shift to the right, favoring the formation of products (HSO₄⁻ and CN⁻). Conversely, if you increased the concentration of products (HSO₄⁻ or CN⁻), the equilibrium would shift to the left, favoring the formation of reactants (SO₄²⁻ and HCN).

Without the equilibrium constant (K) or any other information about the reaction conditions, we cannot definitively say if the reaction is reactants favored or products favored.

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Answer:

B and C

Explanation:

is it multiple choice question??

Van der Waals forces are the interaction between the molecules and the atoms. It increases with an increase in the molecular size and the number of electrons. Thus, options B and C are correct.

Van der Waals forces are the weak forces of attraction and repulsion present between the atoms and the molecules of the compounds. They are also called London Dispersion Forces and dipole-dipole forces.

An increase in the number of electrons and size of the molecule increases the surface area and the electron cloud which in turn, increases the Van der Waals force.

The intermolecular force increases as in large atoms or molecules the valence are held loosely as they are far from the nucleus or the center of the atom.

Therefore, the size and the electron increase the Van der Waals force.

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a) The unknown element that Kevin has is a metal.

Since the unknown element conducts heat, burns with a colored flame, and has a shiny surface- these are the characteristic properties of metals.

b)The piece of evidence that helped to decide was the conduction of heat, orange-colored flame, and shiny surface.

The information provided states that the element is a good conductor of heat as the other end gets heated and burns with an orange-colored flame and also has a shiny surface. These properties confirm that the element is Metal.

Properties of metal-

Properties of non-metal-

From the properties stated it is confirmed that the unknown element is a metal.

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Answer:

the mass in grams for 25 atoms w is 763

It is difficult to determine the exact number of signals that would be seen in the carbon-13 (¹³C) nuclear magnetic resonance (NMR) spectrum without knowing the specific compound being analyzed.

In general, the number of signals in the ¹³C NMR spectrum is determined by the number of chemically distinct carbon environments in the molecule. Each type of carbon atom in a molecule has a different chemical shift value, which depends on the electronic environment and neighbouring atoms. Therefore, the number of signals seen in the ¹³C NMR spectrum is equal to the number of unique carbon environments in the molecule.

For example, a simple organic molecule such as ethanol (CH₃CH₂OH) has two unique carbon environments: the methyl carbon (CH₃) and the methylene carbon (CH₂). Thus, the ¹³C NMR spectrum of ethanol would show two signals.

More complex molecules may have many different carbon environments, leading to a more complex ¹³C NMR spectrum with many signals.

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The correct option is $26785.To calculate the total cost per equivalent unit using the weighted average method, we need to consider the costs incurred in both the beginning work in process and the units added during the period.

First, let's calculate the equivalent units of production for both conversion and materials:

Conversion costs:

Beginning work in process: 400 units × 20% complete = 80 equivalent units

Units added during the period: 2,000 units × 40% complete = 800 equivalent units

Total equivalent units for conversion = 80 + 800 = 880 equivalent units

Material costs:

Beginning work in process: 400 units × 30% complete = 120 equivalent units

Units added during the period: 2,000 units × 50% complete = 1,000 equivalent units

Total equivalent units for materials = 120 + 1,000 = 1,120 equivalent units

Next, let's calculate the total costs incurred:

Conversion costs:

Beginning work in process cost: $14,880

Costs added during the period: $409,200

Total conversion costs = $14,880 + $409,200 = $424,080

Material costs:

Beginning work in process cost: $9,900

Costs added during the period: $180,080

Total material costs = $9,900 + $180,080 = $189,980

Now, we can calculate the total cost per equivalent unit:

Total cost per equivalent unit = (Total conversion costs + Total material costs) / (Total equivalent units for conversion + Total equivalent units for materials)

Total cost per equivalent unit = ($424,080 + $189,980) / (880 + 1,120)

Total cost per equivalent unit ≈ $267.85

Therefore, the correct option is $26785.

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There are three kinds of Hydrogen in  2-methyl-2-butene

The correct question is

How many kinds of  hydrogen atoms are present in 2-methyl-2-butene

Atom was discovered by Dalton's Atomic theory , he predicted that each element consist of large number of a very small thing known as atom.

In the structure of 2-methyl-2-butene there are 3 types oh Hydrogen

1. Attached to the Carbon atom connecting the methyl ion to the butene

2. Connected to the last Carbon atom

3. Connected to the Carbon bond having double bond.

Therefore there are three kinds of Hydrogen in  2-methyl-2-butene.

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Answer:

4

I think so

have a great day

Answer:

I think it is option one (3)

For the number less than 0.1 such as 0.006, the zeroes to the right of the decimal point but before the first non zero digit show the decimal place of the first significant digit.

There is only one significant figure in the provided number 0.06. The decimal place of the first digit is indicated by the zeros that appear to the right of the decimal point but before the first non-zero digit.

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Answer:

A is the correct answer

Explanation:

Answer:

Explanation:

The volume of a substance when given the density and mass can be found by using the formula

\(volume = \frac{mass}{density} \\\)

From the question we have

\(volume = \frac{78}{7.8} \\ \)

We have the final answer as

Hope this helps you

The vapour pressure of mercury at 340.5°C in atm is 1.06 x 10^(-13)  atm

The normal boiling point of mercury is 356.7 °C.

Given that, the ∆Hvap of mercury = 58.51 kJ/mol

We know that at boiling point, the vapour pressure of the substance is 1 atm and with the increase in temperature, the vapour pressure of the substance also increases. We can use Clausius-Clapeyron Equation to calculate the vapour pressure of mercury at 340.5°C.

Clausius-Clapeyron equation is given by :

log(P2/P1) = - ∆Hvap/R [1/T2 - 1/T1]

Where, P1 = vapour pressure at boiling point of mercury = 1 atm

T1 = boiling point of mercury = 356.7 °C = 629.85 K

T2 = 340.5 °C = 613.65 K

∆Hvap = 58.51 kJ/mol

R = gas constant = 0.0821 L atm/mol K

On substituting the values,

log(P2/1) = - 58510/(0.0821 ) x [1/613.65 - 1/629.85]

log(P2) = 29.87

(P2) =1.06 x 10^(-13)  atm

Thus, the vapour pressure of mercury at 340.5 °C is 1.06 x 10^(-13)  atm(approx).

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Answer:

100g gold ring - 58g gold.

Explanation:

Assuming that the 100% represents the 100g of the gold ring, with a mathematical rule of three we can calculate the 58% of gold:

So, in 100g of the gold ring, there are 58g of gold.

Atoms contains nucleus in its center and electron that revolve around the atom in fixed orbit. Stability is the reason that causes atoms  to bond together to form molecules.

Atom is the smallest particle of any element, molecule or compound. Atom can not be further divided. In the nucleus, proton and neutron are present.

Every atoms want to gain stability. To gain stability atoms have to gain noble gas configuration that is outermost shell must contain 2,8, 18 electrons. The atom should follow octet rule. Stability lowers the energy of an atom.

Therefore stability is the reason that causes atoms  to bond together to form molecules.

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To obtain a mixture of 210 liters containing 30% acid, the chemist needs to use 42 liters of the 20% acid solution, 84 liters of the 40% acid solution, and 84 liters of the 60% acid solution.

To solve this problem, we can use the following system of equations:

x + y + z = 210 (1) (total volume of mixture)

0.2x + 0.4y + 0.6z = 0.3(210) (2) (total amount of acid in the mixture)

z = 3y (3) (given that 3 times as much of the 60% solution is used as the 40% solution)

We can solve this system of equations using substitution or elimination. Using substitution, we can solve for z in equation (3), and substitute into equation (1) to solve for y, and then substitute both values into equation (2) to solve for x.

Substituting z = 3y from equation (3) into equation (1), we get:

x + y + 3y = 210

x + 4y = 210

Substituting z = 3y from equation (3) into equation (2), we get:

0.2x + 0.4y + 0.6(3y) = 0.3(210)

0.2x + 0.4y + 1.8y = 63

0.2x + 2.2y = 63

Solving for x in terms of y from the first equation, we get:

x = 210 - 4y

Substituting into the second equation, we get:

0.2(210 - 4y) + 2.2y = 63

42 - 0.8y + 2.2y = 63

1.4y = 21

y = 15

Substituting y = 15 into the first equation, we get:

x + 4(15) = 210

x = 150

Substituting y = 15 and z = 3y = 45 into the original system of equations, we can check that all three equations are satisfied.

Hence, The chemist needs to prepare 210 liters of a mixture that contains 30% acid. To make this mixture, the chemist will need to use 42 liters of a solution that has 20% acid, 84 liters of a solution that has 40% acid, and 84 liters of a solution that has 60% acid.

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The molecular formula of a compound can be defined as the formula which gives the actual number of atoms of various elements present in one molecule of the compound. Here the formula of the hydrate is

The empirical formula of a compound can be defined as the formula which gives the simplest whole number ratio of atoms of various elements present in one molecule of the compound. It is the simplest formula.

Here, Mass of hydrate = 7.21g

Mass of anhydrous salt =  4.78g

Mass of water =  7.21 - 4.78 = 2.43

molar mass of water = 18 g/mol

no.of moles in 2.43 g = 2.43 /18 = 0.135  moles

molar mass of lithium perchlorate = 106.39 g/mol

no.of moles in 4.78g =4.78 / 106.39 = 0.044 moles

Divide both by 0.044, 0.135 / 0.044  = 3.068 , 0.044 / 0.044  = 1

So the formula is LICIO₄ . 3H₂O

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Answer:

Acceleration decreases

Answer:

its b

Explanation: