Which kind of substance accepts an electron pair?

base

hydroxide ion

acid

alkali

Answer:

If you are in k12 then I think the answer you are looking for is 6

Answer:

In 1966, Dr. Hoffmann recorded for the first time in medicine embryonic movements and the heartbeat of the fetus using an ultrasound system.

Explanation:

Today, ultrasound is a technique widely used by many medical specialties, in the emergency department, in intensive care or in daily practice.

In 1794, the Italian Spallanzani observed that during the flight of bats they did not collide with anything despite being blind. It is then that he theorizes that they emitted sounds imperceptible to the man he would call ultrasounds, which they capture with their ears after bouncing off objects.

In 1842, Christian Doppler's first article on the effect of his name appears.

In 1912, Richardson suggests the use of ultrasonic echoes to detect submerged objects, creating the first ultrasonic generator five years later by Paul Langevin and Chilowsky.

Since then the applications of this new technology have been unstoppable, especially in medicine.

Final answer:

Dr. Hoffmann's ultrasound device is used for both diagnostic imaging, such as fetal monitoring, at high frequency, and therapeutic treatments, such as tumor destruction, at lower frequency, providing non-invasive, safe, and effective medical care.

Explanation:

Dr. Hoffmann's ultrasound device provides significant benefits to society, particularly in the fields of medicine and healthcare. Ultrasound technology operates on the principle of using high-frequency sound waves to create images or induce therapeutic effects within the human body. For diagnostic purposes, such as observing a fetus in the womb, ultrasound imaging tends to use higher frequencies ranging from 5-20 MHz because higher frequencies produce more detailed images, which are essential for accurate monitoring and diagnostics.

Meanwhile, for therapeutic applications, such as destroying cancerous tumors, lower frequencies of 1-3 MHz can generate sufficient heat to damage and destroy tumor cells without harming surrounding tissues, offering a non-invasive treatment option.

These medical applications of ultrasound are just two examples of how this technology has revolutionized healthcare, making it possible to diagnose and treat patients safely, effectively, and without invasive surgical procedures. Moreover, the development and improvement of ultrasound devices contribute to ongoing research and the discovery of even more applications in various fields beyond medicine.

Answer : The number in scientific notation will be, [tex]1.6456\times 10^3[/tex]

Explanation :

Scientific notation : It is defined as the way or representation of expressing the number that are too big or too small that is written in the decimal form. That means always written in the power of 10 form.

For example : 8000 is written as, [tex]8\times 10^3[/tex]  and 0.0008 is written as, [tex]8\times 10^{-4}[/tex]

As we are given that the number is, 1645.6

This number is written in scientific notation as, [tex]1.6456\times 10^3[/tex]

Therefore, the number in scientific notation will be, [tex]1.6456\times 10^3[/tex]

Answer:

d. They are defined by their different physical features.

Explanation:

Horizons is the term used to designate the layers that make up the soil. Each layer receives a letter as identification and has different characteristics. Each shift was formed by the weathering process, which occurs due to the influence of factors, chemical, physical and biological.

As previously mentioned, each layer has different characteristics from each other, which allow a wide interpretation of the soil. These characteristics are physical grades such as color, texture, clay content, viscosity, etc.

For this reason, we can say that the horizon is defined by its different physical characteristics.

Answer:

H2

Explanation:

It is a diatomic molecule, meaning it is formed through covalent bonding.

Answer:

The answer is of course, D

Explanation:

For example, since potassium (K) is a metal and chlorine (Cl) is a nonmetal, if these two elements combine, they will form an ionic bond. If carbon (C), a nonmetal, and oxygen (O), a nonmetal, combine, they will form a covalent bond.

Answer is: d.Electrons cannot exist in locations other than in specific orbits.

According to the Bohr model of the atom:

1. Energy levels of electrons are discrete (certain discrete values of energy)., that is why hydrogen shows discrete, bright, colored lines.

2. Electrons orbit the nucleus in orbits that have a set size and energy.

3. Electrons can jump from one energy level to another, absorbing or emitting electromagnetic radiation with a frequency ν (energy difference of the levels).

To calculate the molar mass of sulfuric acid (H2SO4), sum the molar masses of hydrogen, sulfur, and oxygen based on their respective quantities, yielding a molar mass of 98.09 g/mol.

To calculate the molar mass of sulfuric acid (H2SO4), you need to sum the molar masses of all the atoms in a molecule of H2SO4. Each atom's molar mass is found on the periodic table: hydrogen (H) has a molar mass of approximately 1.01 g/mol, sulfur (S) has a molar mass of approximately 32.07 g/mol, and oxygen (O) has a molar mass of approximately 16.00 g/mol.

Using these values, you can perform the following calculation:

Add these values together to get the total molar mass of H2SO4:

Molar mass = 2.02 g/mol + 32.07 g/mol + 64.00 g/mol = 98.09 g/mol

This is the molar mass for sulfuric acid, which is essential for various calculations in chemistry, such as determining the number of moles in a given sample or calculating the concentration of solutions.

Iced tea with no ice is a homogeneous mixture. This is because it has a uniform composition and properties throughout, meaning that you can't distinguish between the different parts of the mixture.

When considering whether a substance is a homogeneous or heterogeneous mixture, it's important to look at its physical characteristics. Iced tea with no ice is an example of a homogeneous mixture. Despite the misleading name, the absence of ice does not change the nature of the substance. A homogeneous mixture is defined as a mixture that has uniform composition and properties throughout. This means that you can't distinguish between the different parts of the mixture. Since all portions of the tea mixture are the same, it meets this criterion. On the other hand, a heterogeneous mixture has different compositions and properties in different parts of the mixture.

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Answer : The correct option is, (2) 8 mole of hydrogen will react with 1 mole of sulfur.

Explanation :

The balanced chemical equation is,

[tex]8H_2+S_8\rightarrow 8H_2S[/tex]

By the stoichiometry we conclude that, 8 moles of hydrogen react with 1 mole of sulfur to give 8 moles of hydrogen sulfide.

Hence, the correct options is, (2) 8 mole of hydrogen will react with 1 mole of sulfur.

Final answer:

The volume of HCl needed to neutralize a given amount of Mg(OH)₂ can be found by first writing the balanced chemical equation, determining the moles of Mg(OH)₂, calculating the moles of HCl required, and then using the molarity of the HCl solution to find the necessary volume.

Explanation:

To calculate the volume of HCl needed to neutralize a certain amount of Mg(OH)₂, we first need to write the balanced chemical equation for the reaction:

Mg(OH)₂ + 2 HCl -> MgCl₂ + 2 H₂O

From the equation, we see that it takes 2 moles of HCl to neutralize 1 mole of Mg(OH)₂. Say we calculate the moles of Mg(OH)₂ using its molar mass, then we can determine the moles of HCl required. After that, using the molarity of the HCl solution, we can find the volume of HCl needed.

For example, assuming we have x moles of Mg(OH)₂:

Moles of HCl required = 2x moles

Volume of HCl = Moles of HCl / Molarity of HCl solution

The volume calculated will give us the answer to how much HCl is required to neutralize the Mg(OH)₂.

C.  Cu undergoes reduction.

Answer: C.) Cu undergoes reduction.

Explanation:

[tex]Fe(s)+CuSO_4(aq)\rightarrow FeSO_4(aq)+Cu(s)[/tex]

I)  Oxidation reaction : involves loss of electrons and there is an increase in oxidation state number.

[tex]Fe\rightarrow Fe^{2+}+2e^-[/tex]

Fe metal has undergone oxidation, as its oxidation state is changing from 0 to +2 in [tex]FeSO_4[/tex].

ii) Reduction reaction : involves gain of electrons and there is a decrease in oxidation state number.

[tex]Cu^{2+}+2e^-\rightarrow Cu[/tex]

Copper(II) ion has undergone reduction, as its oxidation state is changing from 2+ to 0. Copper ions are getting converted into copper metal.

Answer is: C. Water can dissociate many ionic compounds through ion-dipole interactions.

For example, dissociation of potassium bromide: KBr(aq) → K⁺(aq) + Br⁻(aq).

Some ionic compounds cannot dissociate in water, for example calcium sulfate (CaSO₄), silver chloride (AgCl), lead(II)-carbonate (PbCO₃).

An ion-dipole is electrostatic interaction between a charged ion (cations and anions) and a molecule that has a dipole (in this example water).

Dipole is a separation of positive and negative charges. In water, hydrogen has positive and oxygen has negative charge.

Answer:

voltage difference

Explanation:

Remember, a Difference in voltage must exist in order to have current flow.