Why are electrons important?

Answer:

They are normally unreactive with other elements.

Explanation:

Study island :)

Answer:

Explanation:

In fire and arson cases evidences like volatile fuel in the sediment debris can be collected. The debris should be collected in an air-tight container like tin or paint box and bottles so as to prevent the evaporation of the fuel. The type of fuel used for setting up the fire is an important evidence.

Plastic bags should not be used because the plastic can react with the fuel components and may react with the fuel components in debris and the evidence will become futile.

Answer: Option (a) is the correct answer.

Explanation:

Since, it is given that energy is absorbed by the water molecules resulting in a decrease in water's temperature, that is, there will also be a decrease in the energy of molecules.

As a result, molecules will come closer to each other. This means that the diagram (a)  best illustrates the energy change of this dissolving process.

Answer:

A.

Explanation:

The energy is absorbed by the water, it means that the system is losing heat, so, the difference of energy must be negative, the initial energy must be higher than the final energy.

For the reaction happens, the reactants must gain energy to overtake the activation energy, and for that, the reaction can occur.

Only letter A represents a system that the final energy is higher than the initial, and the system gains energy at the beginning.

Barium: 2 electrons, Sodium: 1 electron, Aluminum: 3 electrons, Oxygen: 6 electrons

The number of electrons in the highest occupied energy level can be determined by looking at the electron configuration of each element. For barium (Ba), the electron configuration is 2-8-18-18-8-2, so there are 2 electrons in the highest occupied energy level. Sodium (Na) has an electron configuration of 2-8-1, so there is 1 electron in the highest occupied energy level. Aluminum (Al) has an electron configuration of 2-8-3, so there are 3 electrons in the highest occupied energy level. Oxygen (O) has an electron configuration of 2-6, so there are 6 electrons in the highest occupied energy level.

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Answer:

1 65mL

Explanation:

The best reason to use titration for monitoring the effects of acid rain on drinking water is: to determine the concentration of acid in drinking water. Option A is correct.

Titrations are a well-established quantitative analysis technique that allows scientists to accurately measure the concentration of acids or bases in a solution. This can be particularly useful in environmental chemistry, where it is important to understand the acidity of drinking water due to potential contamination from acid rain.

By applying titration methods, one can detect the exact concentration of acidic species and thus assess their impact on drinking water quality. These methodologies are reliant upon accurately determining the equivalence point, which is often indicated by a change in color for a selected pH indicator, during the titration process.

Hence, A. is the correct option.

The complete question is:

Which of the following would be the best reason to use titration for monitoring the effects of acid rain on drinking water?

A. to determine the concentration of acid in drinking water

B. to find out if the drinking water contains helpful nutrients for the body

C. to find out if there are other poisonous chemicals in the drinking water

D. to determine the molar ratio of acid to base in the drinking water

Answer:

C/boiling point

Explanation:

Fractional distillation is a process that is often employed to separate various liquids from a mixture of liquids based on the respective boiling points. As the liquid mixture is heated, the component with the lowest boiling point will vaporize first and can be separated out through a condenser.

Crude oil is a mixture of several volatile hydrocarbons each having a different boiling point. Therefore, the difference in boiling point can be used to separate them through the method of fractional distillation

The components of crude oil are separated by their boiling points during the process of large-scale fractional distillation, where each substance condenses at different levels of the fractionating column.

The components of crude oil can be separated in a refinery using a process called large-scale fractional distillation. The property that allows this separation is the different boiling points of the substances contained in crude oil. When the crude oil is heated in a fractionating column, its components vaporize at different temperatures due to their various boiling points. The vapor rises through the column until it reaches a level where the temperature is low enough for it to condense back into a liquid. The components with higher boiling points condense near the bottom of the column, where the temperature is higher, while those with lower boiling points condense higher up where the temperature is cooler.

This process results in the collection of simpler mixtures of hydrocarbons and other petroleum compounds at different levels of the column. These collected liquids are then used for various applications, such as diesel fuel, kerosene, and gasoline. Boiling point differences are essential for this separation technique, making it the correct answer (C) to the question. Density, magnetism, and physical state do not serve as the primary basis for separation in this context.

The following pairs of elements would most likely exhibit similar properties:

The chemical properties and behavior of elements are determined by the their valence electrons. Elements with the same number of valence electrons will exhibit similar chemical properties.

The number of valence electrons can be determined easily from the periodic table. In the periodic table the elements are arranged in columns and rows. Columns are called the groups and the rows are the periods. From left to right, each group is numbered from 1 to 18. The group number gives information about number of valence electrons of the element:

Elements that belong to the same group have similar chemical properties.

Potassium and Lithium are both Group 1 element and have one valence electron. They are both very reactive with water. They form an alkaline solution with water.

Neon and Krypton are both Group 18 or Noble Gases. Both elements have filled valence shells with eight electrons and are very stable and quite unreactive.

Keywords: chemical properties, groups,

Answer:

When determining the types of chemical reactions.

Explanation:

Hello,

In this case, in order to establish the different types of chemical reactions, several experiments are carried out the determine whether a chemical reaction is synthesis, decomposition, double displacement, double displacement or combustion. Such experiments consist on the combination of different of reactants under varied conditions in order the appreciate the reaction behavior over the time, changes in color, temperature changes and formed products that suggest the type of reaction.

Once the observations are set throughout the experiments, one provides the scientific knowledge that in this case will help to differentiate such types of chemical reactions.

Best regards.

Representative elements are also known as Group A elements and cover a wide range of properties in the periodic table. They do not include the transition elements, which are referred to as Group B elements.

The representative elements in the periodic table are also known as the Group A elements. These elements include Groups 1A through 8A, excluding the transition metals, which are the Group B elements. The representative elements are so named because they exhibit a wide range of physical and chemical properties, representing almost all possibilities. In contrast, Group B elements or the transition elements, have their own unique properties different from representative elements.

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Answer:

            Box 1  = Sodium Chloride

           Box 3  =  Covalent Bond

Explanation:

Naming NaCl:

                     Ionic compounds are named as;

          i) The positive specie is named first.

          ii) The negative specie is named after.

Example: In NaCl, Sodium is the positive cation i.e. Na⁺ hence, it is named first followed by the name of negative anion which is Cl⁻ (chloride). Therefore, the name given to NaCl is Sodium Chloride.

Covalent Bond:

                This type of bond is formed between atoms by mutually sharing their valence electrons. The type of bond depends upon the electronegativity difference between the atoms. If the electronegativeity difference is greater than the bond will be polar covalent bond or if the difference is small than the bond will be non polar colvalent bond.

A computer and a concentration probe

Answer:

chromium (Cr)

Explanation:

Final answer:

Chromium (Cr) is the transition metal among the listed elements. It falls under the first transition series in the d-block of groups 3-12 on the periodic table.

Explanation:

Among the listed elements, chromium (Cr) is a transition metal. Transition metals fall within groups 3-12 on the periodic table and include the d-block elements, which are typically divided into four transition series. Chromium is part of the first transition series.

Other elements listed such as francium (Fr), beryllium (Be), gallium (Ga), and bismuth (Bi) are not considered transition metals. Francium is an alkali metal, beryllium is an alkaline earth metal, gallium is a post-transition metal, and bismuth is considered a metalloid or post-transition metal, but not a transition metal.

Answer: KOH

Explanation:I JUST TOOK IT

I am unsure if this is correct (especially since I'm very late), but here are the possible answer choices to this question:

O a pure substance

O a type of a mixture

O a pure compound

O an impure substance

The answer to this is a pure substance (1st option).

Answer: Renewable fuels derived from biological matter are called biofuels.

Explanation:

Bio fuels are the fuels which are derived from plants, algae or from the waste of animals. Unlike fossil fuels they are produced from renewable resources  which can be replenished again and again.

For example; ethanol from corns and sugarcane, green diesel from algae etc.

your answer is C. To confine a fission reaction

i just took the test

Answer:

Plate tectonics refers to the plate tectonic theory. According to this theory, the earth's lithosphere is divided into many parts which are commonly known as plates. These are of two types, the continental and the oceanic crust (plate). These plates move over the less dense layer of the asthenosphere from one place to another due to the creation of convection current in the layer of the mantle. This type of current forms because of the heat energy provided from the extreme internal part of the earth. This theory was simple and universally accepted and replaced the theory of continental drift discovered by Alfred Wegener.