Which mass of kcl would you add to water to make a 2.00 l of a 1.20-m solution?

Final answer:

The atomic number on the periodic table indicates the number of protons in the nucleus of an atom of that element, defining its identity. This number is usually found at the top of the element's square on the table, allowing for easy identification and distinction between elements.

Explanation:

The atomic number on the periodic table tells you the number of protons found in the nucleus of the atom of that element. Each element on the periodic table has a unique atomic number, which is usually displayed at the top of the element's square.

This number is crucial because it defines the identity of the element; for instance, hydrogen has an atomic number of 1, meaning all hydrogen atoms have 1 proton in their nucleus. Similarly, helium has an atomic number of 2, indicating that every helium atom has exactly 2 protons in its nucleus.

The periodic table arranges elements in increasing atomic number, and this is the characteristic that makes each element unique compared to all others.

By looking at the periodic table, you can determine the atomic number of an element, and thus know how many protons its atoms contain. This makes the periodic table an indispensable tool for scientists and students alike.

Answer: B) An element’s oxidation number increases because it lost electrons.

Explanation:

A redox reaction is a chemical reaction in which one or more electrons are transferred between the reactants, causing a change in their oxidation states.

The oxidation state or oxidation number is defined as the sum of positive and negative charges of an atom, which indirectly indicates the number of electrons that the atom has accepted or yielded.

By accepting electrons, the oxidation state of an atom decreases, becoming more negative, and therefore, it is reduced. On the other hand, an element that yields electrons increases its oxidation number and oxidizes.

In this way, an element’s oxidation number increase because it lost electrons, becoming a more positive ion.

Answer: Option (D) is the correct answer.

Explanation:

It is known that elements which belong to same group show similar chemical properties.

This is because elements which lie in the same group have same number of valence electrons. Hence, they tend to show same type of reactivity which makes them exhibit similar chemical properties.

For example, Be, Mg, Ca and Sr are all group 2 elements. Hence, they tend to show similar chemical properties.

Thus, we can conclude that out of the given options Be, Mg, Ca elements have properties similar to those of strontium (Sr).

The quantity of valence electrons in an element's outermost atomic shell lies in what determines that element's valency. For all elements in the same group, the electrical configuration of the outermost shell is the same. Here the correct option is D.

The quantity of valence electrons in an element determines its physical and chemical properties. The number of valence electrons shared by elements belonging to the same group is constant. As a result, the physical and chemical properties of elements belonging to the same group are comparable.

Be, Mg, Ca and Sr are all group 2 elements. Hence, they tend to show similar chemical properties.

Thus, we can conclude that out of the given options Be, Mg, Ca elements have properties similar to those of strontium (Sr).

Thus the correct option is D.

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Answer:

It's D.

Explanation:

Trust me.

Answer : Electrons.

Explanation : The subatomic particle which is responsible for combining the atoms together to form a new substance is ELECTRON.

Electrons are negatively charged tiny particles which are found outside the nucleus and is one of the three subatomic particles. These are responsible for formation of new substance through transfer or sharing of electrons between the atoms of the elements. Mainly the outermost revolving electrons are the ones which undergoes transformation and forms new substance. It influences many physical and chemical properties of the substances.

Carbon fixation is a part of photosynthesis where CO2 is added to RuBP to form 3-PGA and eventually glucose. The process is catalyzed by the enzyme RuBisCO and also involves the stages of reduction and regeneration.

Carbon fixation is a process in photosynthesis where carbon dioxide (CO2) combines with a five-carbon sugar, ribulose bisphosphate (RuBP), to form a six-carbon compound. This reaction is catalyzed by an enzyme called RuBisCO. The six-carbon compound is then broken down into two molecules of 3-phosphoglycerate (3-PGA). This cycle, known as the Calvin cycle, involves not only fixation, but also the stages of reduction and regeneration. Reduction uses ATP and NADPH to convert the 3-PGA into glyceraldehyde 3-phosphate (G3P), some of which is used to build glucose. The remaining G3P is used to regenerate RuBP, using additional ATP, which allows the cycle to continue with more carbon fixation.

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Answer:

Mg2+

Explanation:

An action potential arriving at the presynaptic terminal causes voltage-gated Ca²+ channels to open, allowing calcium ions to enter the cell and triggering the release of neurotransmitters into the synaptic cleft.

When an action potential reaches the axon terminal, it depolarizes the membrane and opens voltage-gated Ca²+ channels. Calcium ions enter the cell and initiate a signaling cascade that causes synaptic vesicles containing neurotransmitter molecules to fuse with the presynaptic membrane. This leads to the release of neurotransmitters into the synaptic cleft.

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Answer:

The correct answer is option C, that is, andesitic.

Explanation:

Andesite is the term used for a fine-grained extrusive rocks family, which are generally light to dark gray in appearance. They generally weather to different shades of brown. Andesite mostly comprises plagioclase feldspar minerals and may also comprise pyroxene, biotite, or amphibole as the dark silicate minerals. It generally does not comprise olivine or quartz.

When atoms loose or gain electrons  in chemical reactions they form ions on loosing electrons they form cations and on gaining electrons they form anions.

An ion is defined as an atom or a molecule which has a net electrical charge. There are 2 types of ions :1) cation 2) anion . The cation is the positively charged ion and anion is the negatively charged ion . As they are oppositely charged they attract each resulting in the formation of ionic bond.

Ions consisting of single atom are mono-atomic ions while which consists of two or more ions are called as poly-atomic ions . They are created  by chemical interactions . They are very reactive in their gaseous state  and rapidly react with oppositely charged ions  resulting in neutral molecules.

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The base-10 logarithm of the number of chlorine atoms is 23.971.

Calculate the number of chlorine atoms that are present in 66.05 g of dichloromethane, CH₂Cl₂. When you have the number, take its log (base 10) and enter it with three decimal places and without units.

Step-by-Step Explanation:

First, determine the molar mass of CH₂Cl₂:

Carbon (C): 12.01 g/mol

Hydrogen (H): 1.01 g/mol (each, so 2.02 g/mol for H₂)

Chlorine (Cl): 35.45 g/mol (each, so 70.90 g/mol for Cl₂)

Total molar mass of CH₂Cl₂ = 12.01 g/mol + 2.02 g/mol + 70.90 g/mol = 84.93 g/mol

Calculate the moles of CH₂Cl₂ in 66.05 g:

66.05 g / 84.93 g/mol = 0.7774 mol CH₂Cl₂

Since each molecule of CH₂Cl₂ contains 2 chlorine atoms, calculate the moles of chlorine atoms:

0.7774 mol CH₂Cl₂ x 2 = 1.5548 mol Cl atoms

Convert moles of chlorine atoms to the number of atoms using Avogadro's number (6.022 x 10²³ atoms/mol):

1.5548 mol x 6.022 x 10²³ atoms/mol = 9.36 x 10²³ chlorine atoms

Take the logarithm base 10 of the result:

log10(9.36 x 10²³ )= 23.971

Therefore, the logarithm (base 10) of the number of chlorine atoms in 66.05 g of dichloromethane, CH₂Cl₂, is 23.971.