Which electron in magnesium is most shielded from nuclear charge?

Answer:

Mechanical energy

Explanation:

Mechanical energy is a result of kinetic energy plus potential energy of an atom due to the motion of electrons. As the electrons move away from the nucleus, that is to the outer orbitals the potential energy increases, and as the electrons move inward towards the nucleus the kinetic energy increases.

The percentage error for the mass measurement is 16.5%.

To calculate the percentage error, we use the formula:

Percentage Error = (|Measured Value - Actual Value| / Actual Value) x 100%

In this case, the measured value is 17.7g and the actual value is 21.2g. Plugging in these values into the formula, we get:

Percentage Error = (|17.7g - 21.2g| / 21.2g) x 100% = |3.5g| / 21.2g x 100%

Since the absolute value of 3.5 is equal to 3.5, the percentage error is:

Percentage Error = (3.5g / 21.2g) x 100% = 16.5%

Answer: D) The effect of gravity on an object

Explanation: We're not talking about mass, we're talking about weight. Weight is measured by the force of gravity on a object. For examples, you might be 100 pounds on Earth but 12 pounds on the moon.

NaCl is extracted multiple times with water to ensure more complete dissolution and improved recovery, as well as to remove impurities for a purified product.

The reason NaCl is extracted with water three times as opposed to only once is primarily due to the principle of solute recovery or purification. When a soluble substance like NaCl is dissolved in water, it may not fully dissolve in a single extraction. By performing multiple extractions, you ensure a more complete dissolution or recovery of the NaCl, which improves the efficiency of the extraction process. Additionally, repeated extractions can help remove impurities that are less soluble in water. Each subsequent extraction with fresh water removes a fraction of the remaining solute and any impurities, leading to a purified product.

Answer:

sulfur

Explanation:

Answer:

No, Water boils faster at higher altitudes.

Explanation:

The heat lost by the metal should be equal to the heat gained by the water. We know that the heat capacity of water is simply 4.186 J / g °C. Therefore:

100 g * 4.186 J / g °C * (31°C – 25.1°C) = 28.2 g * Cp * (95.2°C - 31°C)

Cp = 1.36 J / g °C

Answer:

Physical change

Explanation:

A physical change is a reversible change in the physical properties of a substance.

Let’s look at an example:

Water. Water is made up of 2 hydrogen atoms and one oxygen atoms, H2O.

When the temperature of water decreases, the particles slow down and the liquid turns to ice. When it turns to ice, is it still H2O? Yes! When water changes states, it’s just a physical change. The chemical properties of water DO NOT change!! It’s physical change because when you melt ice, it can goes back to its original form: liquid (water). It can be reversed!

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Here are some examples of ways to cause physical changes:

The change that can be easily reversed is a physical change, because it doesn't alter a substance's basic identity - it just changes its form. This is unlike chemical changes, which fundamentally alter a substance and thus cannot be easily reversed.

The change that can be easily reversed is a physical change. This is because physical changes don't alter the basic identity of the substance - they just change its form. For example, when you melt ice into water, that's a physical change because the water is still H2O, just in a different state. If you put it back in the freezer, it can change back into ice. This is unlike a chemical change, such as burning wood into ash and smoke. In this case, the wood can't be changed back into its original form because its chemical properties have been altered.

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Answer: A.  One or more substances with different chemical properties will form.

Explanation:

Chemical change is defined as a change in which rearrangement of atoms take place and leads to formation of new substance. Thus as new substances are formed, the chemical properties of the products will alwys be different from the chemical properties of reactants.

Physical change is defined as a change in which change in shape, size or state of the substance takes place. No new substance is formed.

Chemical change may involve following changes:

1) Formation of precipitates

2) Absorption or evolution of heat

3) Color change

4) Evolution of gas

Answer: Option (C) is the correct answer.

Explanation:

In a solid, molecules are held together by strong intermolecular forces of attraction. As a result, they are unable to move from their initial place but they can vibrate at their mean position.  

Hence, in solid substances the molecules have low kinetic energy and they have fixed shape and volume.

In gases, the molecules are held by weak Vander waal forces. Hence, they have high kinetic energy due to which they move rapidly from one place to another leading to more number of collisions.  

Hence, gases are able to expand more rapidly as compared to liquids and solids.

Thus, we can conclude that the statement atoms of both are moving, is true about both a solid and a gas.

The mass of Y that reacted is 66.7 g.

In compound X, the mass ratio of carbon to hydrogen is 14.13 g C : 2.96 g H. This number ratio supports the law of multiple proportions, indicating that X and Y are different compounds. To find the mass of Y that reacted, you can subtract the mass of X from the total mass of XY:

Mass of Y = Total mass of XY - Mass of X
Mass of Y = 78.9 g - 12.2 g
Mass of Y = 66.7 g

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A glass of grapefruit juice contains ten times more H+ than a glass of tomato juice.

The pH of any solution is determined with the help of hydrogen ion concentration. For example, if a neutral solution has a pH of 7, it means that the concentration of H+ ions is [tex]10^-^7[/tex]. In other words, it may contain 0.0000001 mol of hydrogen ions in a solution of 1 liter.

According to the question,

The pH of Grapefruit juice is = 3

The concentration of H+ ions = [tex]10^-^3[/tex] = 0.001 mol.

The pH of Tomato juice = 4.

The concentration of H+ ions = [tex]10^-^4[/tex] = 0.0001 mol.

From the above concentration of both hydrogen ion concentrations, it is clearly illustrated that a glass of grapefruit juice contains ten times more H+ than a glass of tomato juice.

To learn more about pH and hydrogen ion concentrations, refer to the link:

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When a sulfur ion with 16 protons and 17 electrons loses one electron, the resulting charge is 0. This is because the number of protons equals the number of electrons, resulting in no overall charge.

The question here asks: If a sulfur ion has 16 protons and 17 electrons and this ion loses one electron, what is the resulting charge? In order to answer this, it's important to understand that the charge of an ion is determined by the difference between the number of protons and the number of electrons. Initially, the sulfur ion had one more electron than protons, giving it a charge of -1.

However, when it loses an electron, the number of protons and electrons equal each other, resulting in a neutral ion with a charge of 0. Therefore, when a sulfur ion with 16 protons and 17 electrons loses one electron, the resulting charge is 0. This is because the number of negatively charged electrons now equals the number of positively charged protons, resulting in no overall charge.

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Final answer:

According to Dalton's atomic theory, when elements react, their atoms combine in simple whole number ratios to form chemical compounds. In chemical reactions, atoms can be combined, separated, or rearranged, but they are neither created nor destroyed.

Explanation:

According to Dalton's atomic theory, when elements react, their atoms combine in simple whole number ratios to form chemical compounds. In chemical reactions, atoms can be combined, separated, or rearranged, but they are neither created nor destroyed. This means that the number of atoms in the reactants is equal to the number of atoms in the products.

Helium is the second lightest element and the lightest monatomic element in its natural state. It is part of the noble gases, inert and does not react with other elements, and has various applications due to its low density.

Helium is a colorless, odorless, and tasteless element that is found naturally in the gas state. It is known for being the second most abundant element in the universe and the lightest monatomic element. A helium atom consists of a nucleus with 2 protons and usually 2 neutrons and is enveloped by 2 electrons, resulting in a complete valence shell making it chemically inert. Helium has an atomic number of 2, making it the second element in the periodic table right after hydrogen, which is the first and simplest element having only one proton and one electron and generally forms H₂ molecules. Contrary to helium, hydrogen is the lightest gas overall since it forms diatomic molecules. Nonetheless, if we consider single atoms, then helium atoms are indeed heavier than hydrogen atoms.

Helium's unique characteristics such as its low boiling point, low density, and lack of chemical reactivity arise from its filled electron shell, where no further electrons can be added. These properties make helium a noble gas and it is placed at the top of this group in the periodic table. Its low density of only 0.164 g/L at 25°C and 1 atm pressure also makes helium ideal for applications such as filling balloons.

Answer:

4

Explanation:

Si has atomic number 14 so the electronic configuration 2,8,4

Valence electrons of Si and C are shared in covalent bonding.

In a covalent bond, valence electrons are shared between atoms. The number of valence electrons an element has determines how many covalent bonds it can form. For example, carbon (C) has 4 valence electrons, so in a covalent bond, these 4 electrons are shared with other atoms.

Similarly, silicon (Si) also forms covalent bonds by sharing its valence electrons. Silicon has 4 valence electrons like carbon, so it can form 4 covalent bonds as well.

To find the number of molecules in a given amount of substance, use Avogadro's number. The mass of a given number of moles can be calculated by multiplying the number of moles by the molar mass.

To determine the number of molecules in a given amount of substance, we can use Avogadro's number. Avogadro's number is approximately 6.022 × 1023 and represents the number of particles in one mole of a substance.

For example, in 1.30 mol of O2, there would be 1.30 × 6.022 × 1023 molecules of O2.

To find the number of molecules in the other given amounts, you can use the same approach.

The mass of 3.64 mol of iron (Fe) can be calculated by multiplying the number of moles by the molar mass of iron. The molar mass of iron is approximately 55.85 g/mol, so the mass of 3.64 mol of iron would be 3.64 × 55.85 g.

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