Radha takes some blue solution in a test tube and then puts some drops of lemon juice into it. She leaves the solution for an hour. After she comes back, she looks at the solution and concludes that a chemical change has happened in it. What might have occurred for her to conclude this? * (1 Point)

1.The solution evaporated from the test tube.

2.The drops of lemon juice formed a layer on the solution.

3.The solution changed colour from blue to red.

4.The drops of lemon juice increased the weight of the solution.​

Answer: Thus 663 J of heat  is released when 27.6 g \(PCl_3\) cools from 83.1 °C to 55.6 °C

Explanation:

The quantity of heat required to raise the temperature of a substance by one degree Celsius is called the specific heat capacity.

\(Q=m\times c\times \Delta T\)

Q = Heat released = ?

m = mass of substance = 27.6 g

C = specific heat capacity = \(0.874J/g^0C\)

Initial temperature= \(T_i\) = \(83.1^0C\)

Final temperature  = \(T_f\)  = \(55.6^0c\)

Change in temperature ,\(\Delta T=T_f-T_i=(55.6-83.1)^0C=-27.5^0C\)

Putting in the values, we get:

\(Q=27.6g\times 0.874J/g^0C\times -27.5^0C=-663J\)

As the value of q is negative, it means the heat has been released and it is 663J

Answer:

The excited state electron configuration of an atom indicates the promotion of a valence electron to a higher energy state.

Answer:

a. The Zn and HCl both retained their identity.

Answer:

C should be the answer

Explanation:

energy required to raise 1 gram of a sample by 1 kelvin or degree celsius

Answer:

C)

one, one

Explanation:

Answer:

m = 29.6 grams

Explanation:

Given that,

Number of moles = 0.540

The molar mass of manganese = 54.93 g/mol

We know that,

Number of moles = given mass/molar mass

\(m=n\times M\\\\m=0.540 \times 54.93\\\\m=29.6\ g\)

So, the required mass of the Manganese is equal to 29.6 grams.

The statement "increasing the force will increase the moment" is true.

This is because the moment is a measure of the turning effect of a force on an object about a pivot point. It is defined as the product of the force and the perpendicular distance between the force and the pivot point. The unit of moment is the newton-meter (Nm) or the joule (J).When a force is applied to an object, it will produce a moment about the pivot point if the force is not acting along the same line as the pivot point. The magnitude of the moment depends on the force applied and the distance of the force from the pivot point. As the force increases, the moment also increases, provided that the distance from the pivot point remains constant. Conversely, if the force remains constant, but the distance from the pivot point increases, the moment also increases. This is because the perpendicular distance is directly proportional to the moment, meaning that a longer distance results in a larger moment.Therefore, it can be concluded that increasing the force applied to an object will increase the moment produced about a pivot point.

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The most important safety measure to follow when using an acid in a classroom laboratory is wearing gloves, wear face shield and protective clothing etc

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The number of moles for the quanity 8.06 x\(10_{21\) atoms of Pt​ is approximately 2.61 grams.

To calculate the number of moles for a given quantity of atoms, we can use Avogadro's number and the molar mass of the element. Avogadro's number is 6.022 x 10²³ atoms/mol.

In this case, you have 8.06 x 10²¹ atoms of Pt. To find the number of moles, divide this quantity by Avogadro's number:

8.06 x 10²¹  atoms Pt / 6.022 x 10²³  atoms/mol = 0.0134 mol Pt

So, there are approximately 0.0134 moles of Pt in 8.06 x 10²¹  atoms of Pt.

The molar mass of Pt (platinum) is 195.08 g/mol. To convert the number of moles to grams, multiply the number of moles by the molar mass:

0.0134 mol Pt x 195.08 g/mol = 2.61 g Pt

Therefore, there are approximately 2.61 grams of Pt in 8.06 x10²¹  atoms of Pt.

In summary, the number of moles for the quantity 8.06 x 10²¹ atoms of Pt is approximately 0.0134 moles. This is equivalent to approximately 2.61 grams of Pt. Remember to use Avogadro's number and the molar mass to perform these calculations accurately.

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Answer:

Explanation:

To calculate the molar internal energy of a gas at a given temperature, you need to know the molar specific heat capacities at constant volume and constant pressure for the gas. These values are typically provided in tables of thermodynamic data, which can be found in various sources such as textbooks or online. Since you mentioned that you want to take the translational and rotational degrees of freedom into consideration, you will need to use the molar specific heat capacity at constant volume, which accounts for these degrees of freedom.

Once you have the molar specific heat capacity at constant volume for the gas, you can use the equation U = Cv * T, where U is the molar internal energy, Cv is the molar specific heat capacity at constant volume, and T is the temperature in kelvins. In your case, the temperature is 298.15 K, so plugging in the appropriate values and solving for U will give you the molar internal energy of carbon dioxide at that temperature.

It's important to note that the molar specific heat capacity at constant volume is typically a function of temperature, so you will need to use the appropriate value for the temperature you are interested in. Additionally, different sources may provide slightly different values for the molar specific heat capacity, so it's always a good idea to consult multiple sources to get a sense of the range of possible values.

The volume of hydrogen gas produced is 19.8 L.

The balanced chemical equation is given as;

Zn + 2HCl → ZnCl₂ + H₂

from the reaction above;

1 mole of Zn = 1 mole of H₂

number of mole of 48.5 g Zn  is calculated as

48.5 g  /65.4 g/mol

= 0.74 mol Zn  = 0.74 mol H₂

The volume of hydrogen gas produced is calculated as follows;

PV = nRT

where;

T = 27°C + 273 = 300 K

V = nRT/P

V = (0.74 x 0.08206 x 300) / (0.921)

V = 19.8 L

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Answer:

Take 1ml of given compound in a dry test tube. Add a few drops of ceric ammonium nitrate reagent and shake the solution well. Observe the solution. If red precipitate appears then the presence of alcoholic group is conformed.

Answer:

3×10^11 uw

Explanation:

=1kw=1×10^9

300kw=?

=300×1×10^9

=3×10^11uw

The mass of sulfur dioxide required is approximately 6.36 grams.

To determine the number of grams of sulfur dioxide (SO2) required to exert a pressure of 0.705 atm in a 2.50L tank at 0 °C, we can use the ideal gas law equation: PV = nRT.

First, we need to convert the temperature from Celsius to Kelvin by adding 273.15, so the temperature becomes 273.15 K. The ideal gas constant (R) is 0.0821 L·atm/(mol·K).Rearranging the ideal gas law equation to solve for the number of moles (n), we get n = PV / RT.

Plugging in the given values, n = (0.705 atm) * (2.50 L) / [(0.0821 L·atm/(mol·K)) * (273.15 K)]. Calculating this expression, we find that n is approximately 0.0993 moles.The molar mass of sulfur dioxide is 64.06 g/mol (32.06 g/mol for sulfur + 2 * 16.00 g/mol for oxygen).

Finally, we can calculate the mass of sulfur dioxide using the formula: mass = n * molar mass = 0.0993 moles * 64.06 g/mol. Thus, the mass of sulfur dioxide required is approximately 6.36 grams.

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Answer:

erosion.

Explanation:

A methane molecule (CH4) is considered symmetrical because it possesses a symmetric structure and exhibits symmetry operations.

Symmetry refers to a balanced arrangement of elements that can be divided into equal parts by a plane, axis, or center. In the case of methane, it exhibits several symmetrical characteristics.

Firstly, methane has a tetrahedral molecular geometry, with the carbon atom at the center and four hydrogen atoms positioned around it. This geometry ensures that the molecule is symmetrical in terms of its spatial arrangement.

Each hydrogen atom is located at one of the vertices of the tetrahedron, forming equal angles and distances with respect to the central carbon atom. This symmetry is maintained regardless of the orientation of the molecule.

Additionally, methane possesses rotational symmetry. It can be rotated around any of the carbon-hydrogen bonds, and the molecule will retain its overall appearance.

The symmetry of methane arises from its molecular structure and the equal distribution of electron density around the central carbon atom. The four hydrogen atoms are bonded to the carbon through sigma bonds, which have a cylindrical symmetry. This balanced arrangement of the atoms contributes to the overall symmetry of the molecule.

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Answer:

x = w/v

General Formulas and Concepts:

Pre-Algebra

Explanation:

Step 1: Define

v = w/x

Step 2: Solve for x

Answer:

Temperature

Explanation:

Temperature measures the average kinetic energy of the particles in a substance. Thermal energy measures the total kinetic energy of the particles in a substance. The greater the motion of particles, the higher a substance's temperature and thermal energy.

Answer:

B. PROTONS EXHIBIT STRONGER PULL ON OUTER f ORBITALS

Explanation:

Lanthanide contraction is the greater than normal decrease in the ionic radius of the lanthanide series from atomic number 57 to atomic number 71. This decrease is rather not expected of the ionic radii of these elements and they result in the greater decrease in the subsequent series of the lanthanides from the atomic number 72. The cause of which is as a result of the poor shielding effects of the nuclear charge around the electrons of the f orbitals. So therefore, protons are strongly pulled out of the 4f orbital and as a result of the poor shielding effect which causes the electrons of the 6s orbitals to be drawn more closer to the nucleus and hence resulting in a smaller atomic radii. It is worthy to note that the shielding effects of the inner electrons decreasing from s orbital to the f orbital; that is s > p > d > f. So from the decrease in the shielding effects from s to the f orbitals, lanthanide contraction results from the inability of the orbitals far away from s like the 4f orbiatls to shield the outermost shells of the lanthanide elements. So the cause of lanthanide contraction is the action of the protons which strongly pull the electrons of the f orbitals because of the poor shielding effects due to the distance of this orbital from the nucleus.

Answer:

B) Protons exhibit a stronger pull on outer f orbitals than on d orbitals.

Explanation:

According to Newton's second law, force equals mass multiplied by acceleration. As a result, in a car accident, the force exerted by the vehicle and its occupants decreases as the time required for the vehicle to stop increases.

We clearly observed in the Exploration that when two cars collide, each feels a force from the other.

According to Newton's third law, when one object exerts a force on another, the second object feels an equal and opposite force exerted by the first object. This is very clear in the two-object collision.

The force with which your body is struck in a collision is referred to as crash force. Crash force is equal to your body weight multiplied by the vehicle's speed.

Newton's second law states that force equals mass multiplied by acceleration. As a result, the force exerted by the vehicle and its occupants in a car accident decreases as the time required for the vehicle to stop increases.

Thus, this way it hits the car.

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6.02 x \(10^{20\) formula units of MgCl₂ is equal to 0.1 moles of MgCl₂.

To convert formula units of MgCl₂ to moles of MgCl₂, we need to use Avogadro's number, which relates the number of formula units to the number of moles.

Avogadro's number (NA) is approximately 6.022 x 10^23 formula units per mole.

Given that we have 6.02 x 10^20 formula units of MgCl₂, we can set up a conversion factor to convert to moles:

(6.02 x 10^20 formula units MgCl₂) * (1 mol MgCl₂ / (6.022 x 10^23 formula units MgCl₂))

The formula units of MgCl₂ cancel out, and we are left with moles of MgCl₂:

(6.02 x 10^20) * (1 mol / 6.022 x 10^23) = 0.1 mol

Therefore, 6.02 x 10^20 formula units of MgCl₂ is equal to 0.1 moles of MgCl₂.

It's important to note that this conversion assumes that each formula unit of MgCl₂ represents one mole of MgCl₂. This is based on the stoichiometry of the compound, where there is one mole of MgCl₂ for every one formula unit.

Additionally, this conversion is valid for any substance, not just MgCl₂, as long as you know the value of Avogadro's number and the number of formula units or particles you have.

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Answer:

The identity of unknown substance is Barium.

Explanation:

The given compound has a formula of MCl2. And the percentage of chlorine in this compound is said to be 34.1 %. But, we know that the mass of chlorine in this compound is, 35.5*2 = 71 g

Therefore, if we let x be the total mass of the compound, then:

34.1% of x = 71 g

(0.341)x = 71 g

x = 71 g/0.341

x = 208.2 g

Hence, the mass of other atom M, must be:

M = x - 71 g

M = 208.2 g - 71 g

M = 137.2 g

Now, we look into periodic table in group II. We find that the element is Barium with atomic mass of 137 g.

The identity of unknown substance is Barium.

Barium forms a metal chloride whose percentage of chlorine is 34.1 %. The unknown substance is barium chloride.

We have a Group II metal chloride with a general formula MCl₂. The molar mass of Cl⁻ is 35.45 g/mol. The mass of 2 moles of Cl⁻ is:

\(2 mol Cl^{-} \times \frac{35.45g Cl^{-} }{1mol Cl^{-} } = 70.90g Cl^{-}\)

70.90 g represents 34.1% of 1 mole of MCl₂. The molar mass of MCl₂ is:

\(70.90gCl^{-} \times \frac{100gMgCl_2}{34.1gCl^{-} } = 208gMgCl_2\)

208 g of MCl₂ contains 70.90 g of Cl⁻. The mass of M²⁺ in 1 mole of MCl₂ is:

\(mMCl_2 = mCl^{-} + mM^{2+} \\\\mM^{2+} = mMCl_2 - mCl^{-} = 208g-70.9 g = 137.1 g\)

Barium has a molar mass of 137.3 g/mol, so M must be barium. The unknown substance is barium chloride.

Barium forms a metal chloride whose percentage of chlorine is 34.1 %. The unknown substance is barium chloride.

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Answer:

Observation

Explanation:

Observation is the first step in scientific method. First of all you observe anything or any activity.

Then you think about how it is going this way. If it happens so and so what will happen... then perform experiments. Etc

Observation

Hypothesis

Theory

Experiments

Law

Some of the neurons in the central nervous system and the medulla of the adrenal glands both create adrenaline. In a stressful circumstance, adrenaline is immediately released into the blood, sending signals to the organs to trigger a certain response, within a few minutes.

What causes the body's adrenaline to rise?

Temporarily elevated adrenaline levels are caused by exercise. The majority of us are familiar with the common signs of adrenaline release, such as: rapid heartbeat, high blood pressure, anxiety, excessive sweating, and palpitations, because most individuals are occasionally subjected to stressful situations.

What body part produces adrenaline?

The inner portion of an adrenal gland called the adrenal medulla regulates the hormones that start the flight or fight response. The primary hormones that the adrenal medulla secretes adrenaline.

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Answer:

Explanation:

The formula for gravitational potential energy is the mass*gravity*height. Therefore, the greater the distance from the ground, the higher the gravitational potential energy.

Answer: The amount of gravitational potential energy an object has depends on mass of the object and height of the object above ground. Objects that are at large height above the ground have more potential energy. Similarly, objects that are at small height above the ground have less potential energy.

Answer:

The Answer will be provided below, please pay attention in class next time so that you don't have to be in a hurry like you are in now.

Explanation: The correct option is:

Both fossil fuels and wind energy can be used to produce electricity. However, burning fossil fuels does pollute the atmosphere, while using Earth's wind does not. Both fossil fuels and wind energy contribute to climate change, but the use of fossil fuels is much more damaging to the environment than the use of wind power.

Fossil fuels are non-renewable sources of energy that are formed over millions of years by the decomposition of organic matter. They release harmful greenhouse gases when burned, contributing to climate change. In contrast, wind energy is a renewable source of energy that uses turbines to harvest the power of wind. Wind energy does not produce any emissions, making it an environmentally friendly alternative to fossil fuels. While wind turbines can have some impacts on wildlife and habitats, the impact is much less severe than the effects of fossil fuel extraction and burning.

Added Part: Fossil fuels are non-renewable sources of energy that are derived from the remains of plants and animals that died millions of years ago. These sources include coal, oil, and natural gas. Wind energy, on the other hand, is a renewable source of energy that is generated by the kinetic energy of wind.

Here are some comparisons between fossil fuels and wind energy:

Environmental Impact: Fossil fuels have a significant negative impact on the environment. Burning fossil fuels produces greenhouse gases that contribute to climate change. The extraction of fossil fuels also has negative impacts on the air, water, and soil. Wind energy, however, has a very small environmental footprint. Wind turbines do not produce any emissions and do not require any water to generate electricity.

Energy Availability: Fossil fuels are abundant and have been the primary source of energy for decades. On the other hand, wind energy is a relatively new source of energy and the technology is still developing. However, the availability of wind energy is significant, as wind is a renewable source that is constantly available.

Sustainability: Fossil fuels are non-renewable, which means they will eventually run out. As the demand for energy continues to increase, the availability of fossil fuels will decrease. Wind energy is a renewable source of energy that will never run out.

Here are some pros and cons of both fossil fuels and wind energy:

Fossil Fuels:

Pros:

Reliable source of energy

High energy density

Large global infrastructure

Cons:

Non-renewable source of energy

Significant environmental impact

Price instability

Wind Energy:

Pros:

Renewable source of energy

Small environmental footprint

Low operating costs

Cons:

High initial costs for building wind turbines

Wind is an inconsistent source of energy

Can create noise pollution for surrounding communities

4.1 The Chemical Equation

LEARNING OBJECTIVES

Define chemical equation.

Identify the parts of a chemical equation.

A chemical reaction expresses a chemical change. For example, one chemical property of hydrogen is that it will react with oxygen to make water. We can write that as follows:

hydrogen reacts with oxygen to make water

We can represent this chemical change more succinctly as

hydrogen + oxygen → water

where the + sign means that the two substances interact chemically with each other and the → symbol implies that a chemical reaction takes place. But substances can also be represented by chemical formulas. Remembering that hydrogen and oxygen both exist as diatomic molecules, we can rewrite our chemical change as

H2 + O2 → H2O

This is an example of a chemical equation, which is a concise way of representing a chemical reaction. The initial substances are called reactants, and the final substances are called products.

Unfortunately, it is also an incomplete chemical equation. The law of conservation of matter says that matter cannot be created or destroyed. In chemical equations, the number of atoms of each element in the reactants must be the same as the number of atoms of each element in the products. If we count the number of hydrogen atoms in the reactants and products, we find two hydrogen atoms. But if we count the number of oxygen atoms in the reactants and products, we find that there are two oxygen atoms in the reactants but only one oxygen atom in the products.

What can we do? Can we change the subscripts in the formula for water so that it has two oxygen atoms in it? No; you cannot change the formulas of individual substances because the chemical formula for a given substance is characteristic of that substance. What you can do, however, is to change the number of molecules that react or are produced. We do this one element at a time, going from one side of the reaction to the other, changing the number of molecules of a substance until all elements have the same number of atoms on each side.

To accommodate the two oxygen atoms as reactants, let us assume that we have two water molecules as products:

H2 + O2 → 2H2O

The 2 in front of the formula for water is called a coefficient. Now there is the same number of oxygen atoms in the reactants as there are in the product. But in satisfying the need for the same number of oxygen atoms on both sides of the reaction, we have also changed the number of hydrogen atoms on the product side, so the number of hydrogen atoms is no longer equal. No problem—simply go back to the reactant side of the equation and add a coefficient in front of the H2. The coefficient that works is 2:

2H2 + O2 → 2H2O

There are now four hydrogen atoms in the reactants and also four atoms of hydrogen in the product. There are two oxygen atoms in the reactants and two atoms of oxygen in the product. The law of conservation of matter has been satisfied. When the reactants and products of a chemical equation have the same number of atoms of all elements present, we say that an equation is balanced. All proper chemical equations are balanced. If a substance does not have a coefficient written in front of it, it is assumed to be 1. Also, the convention is to use all whole numbers when balancing chemical equations. This sometimes makes us do a bit more “back and forth” work when balancing a chemical equation.

Answer:

Answer:

here

Explanation:

There is an easy way to remember how light rays travel through lenses. Light rays passing through a lens always bend toward the thickest part of the lens. Light waves bend toward the thick center in a convex lens. They bend out toward the thick edge in a concave lens.

answer and explanation

we are asked to determine the number of mols of Oxygen in the sample and we can do this using the ideal gas equation

PV = nRT

and when we rearrange the equation to make n subject of the formula, we gent :

n = PV/RT

= (3.21atm x 47.6L) / (0.0821 x 285K)

= 152.796 / 23.3985

= 6.53 mols