Mendeleev noticed that certain similarities in the chemical properties of elements appeared at regular intervals when teh elements were arranged in order of increasing

Answer:

3

Explanation:

Final answer:

Astrology is a pseudoscience because it claims to be scientific but does not follow the scientific method, lacking falsifiable predictions and empirical verification, distinguishing it from legitimate sciences like astronomy.

Explanation:

Astrology is considered a pseudoscience because it is a belief system or practice that is often claimed to be scientific but does not adhere to a valid scientific methodology. It lacks the provision of falsifiable predictions or hypotheses, which is a core principle in the scientific method. Astrology, the practice of using celestial bodies to make predictions about human behaviors, positions itself as having an astronomical foundation, yet it does not engage in empirical and statistical methods that are characteristic of actual sciences like astronomy.

The correct answer to why astrology is a pseudoscience is B. it claims to be, but is not, a science. This is because astrology's methods do not incorporate the systematic observations, carefully-controlled experiments, and rigorous peer review that are the hallmarks of true scientific practice. While the movements and positions of celestial bodies (the subject of astronomy) can be precisely measured and predictions tested against observable outcomes, astrology (the supposed influence of celestial bodies on human life) does not operate within such testable frameworks.

If the internal energy of the products in a reaction is lower than the internal energy of the reactants, this means the reaction is an exothermic reaction and the sign of δe for the reaction is positive.

Internal energy is the property or state function which defines the energy of a substance in the absence of effects due to capillarity and the external electric, magnetic, and other fields.

In this reaction, the internal energy of products is lower than the internal energy of the reactants because the bonds in the products are stronger than those in the reactants, as a result the reaction releases more energy than it consumes. Therefore, the reaction is an example of exothermic reaction.

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Material  deposited directly  by s glacier is called  till (answer C)

Explanation

Till is a heterogenous  mixture  of different  sized   material  deposited  by  moving ice.  This type of till is known as lodgement  till.

The other type of till   is deposited  by  the melting  in place of stagnant  ice  and   is referred to as ablation till.

After  deposition, some till are  reworked by  water.

The percent error of the average result is approximately 8.2%.

To calculate the percent error, use the formula:

[tex]\[ \text{Percent Error} = \left| \frac{\text{Measured Value} - \text{Actual Value}}{\text{Actual Value}} \right| \times 100\% \][/tex]

Given:

Measured Value = Average result =x mL

Actual Value = 34.1 mL

Plug in the values into the formula:

[tex]\[ \text{Percent Error} = \left| \frac{x - 34.1}{34.1} \right| \times 100\% \][/tex]

Now, substitute the average result value (measured value) into the formula. Let's say the average result is 36.9 mL:

[tex]\[ \text{Percent Error} = \left| \frac{36.9 - 34.1}{34.1} \right| \times 100\% \]\[ \text{Percent Error} = \left| \frac{2.8}{34.1} \right| \times 100\% \]\[ \text{Percent Error} = \frac{2.8}{34.1} \times 100\% \]\[ \text{Percent Error} = 0.0821 \times 100\% \]\[ \text{Percent Error} = 8.21\% \][/tex]

So, the percent error of the average result is approximately 8.2%.

Answer: It spreads forming waves

Explanation:

Radiant energy is the one possessed by electromagnetic waves such as visible light,  (IR) rays, ultraviolet (UV) rays, radio waves, etc. The main characteristic of this energy is that it can be propagated in a vacuum, without the need for any material support.

Other properties are:

- It is in motion continuosly

- Travel through space at the speed of 300,000 kilometers per second

- It spreads forming waves.

The atom with the greatest number of valence electrons is I: 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁵. It has 7 valence electrons in the outermost energy level (5p). Thus, the correct option is option C.

Valence electrons are the electrons in the outermost energy level of an atom and are involved in chemical bonding and reactions. Electronic configuration refers to the arrangement of electrons in an atom, ion, or molecule. It describes the distribution of electrons among different energy levels, orbitals, and subshells within an atom or ion.

The electronic configuration is represented using a notation that indicates the energy levels (principle quantum numbers), subshells (s, p, d, f), and the number of electrons in each subshell. The Aufbau principle, Pauli exclusion principle, and Hund's rule are used to determine the order of filling the orbitals and the spin states of the electrons.

Thus, the ideal selection is option C.

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the answer is (#1) independent variable.

A) Endothermic reactions where there is a decrease in entropy.

To determine which type of reaction does not happen spontaneously, we need to consider the Gibbs free energy equation:

Gibbs free energy (G) = Enthalpy (H) - Temperature (T) × Entropy (S)

A reaction is spontaneous if the change in Gibbs free energy (ΔG) is negative.

ΔG = ΔH - TΔS

Where:

ΔH is the change in enthalpy (positive for endothermic reactions, negative for exothermic reactions).

ΔS is the change in entropy (positive for increasing entropy, negative for decreasing entropy).

T is the temperature in Kelvin.

Analysis:

Endothermic reactions with a decrease in entropy:

ΔH > 0 (positive)

ΔS < 0 (negative)

ΔG = ΔH - TΔS

Since ΔH is positive and ΔS is negative, ΔG will be positive if TΔS is not large enough to make ΔG negative. Therefore, this reaction may not be spontaneous.

Exothermic reactions with a decrease in entropy:

ΔH < 0 (negative)

ΔS < 0 (negative)

ΔG = ΔH - TΔS

Although ΔH is negative, TΔS is positive. If ΔH is not sufficiently negative, ΔG can still be positive, making the reaction non-spontaneous.

Endothermic reactions with an increase in entropy:

ΔH > 0 (positive)

ΔS > 0 (positive)

ΔG = ΔH - TΔS

Here, if TΔS is greater than ΔH, ΔG will be negative, making the reaction spontaneous.

Exothermic reactions with an increase in entropy:

ΔH < 0 (negative)

ΔS > 0 (positive)

ΔG = ΔH - TΔS

Both terms are favorable; thus, ΔG will typically be negative, making the reaction spontaneous.

The color of the flame for the compound sodium hydroxide (NaOH) is yellowish orange.

Sodium hydroxide or caustic soda can be described as an inorganic compound with the chemical formula NaOH. Sodium hydroxide is a white solid ionic compound containing sodium cations Na⁺ and hydroxide anions OH⁻ ions.

Sodium hydroxide (NaOH) can be defined as a highly caustic base that decomposes proteins at normal ambient temperatures and can cause severe chemical burns.

Sodium hydroxide is a colorless crystalline solid with a boiling point of 1,388 °C. NaOH has a lower solubility in polar solvents such as ethanol and methanol but is highly soluble in water.

Dissolution of sodium hydroxide in water is a highly exothermic reaction where a huge amount of heat is liberated, posing a danger through the possibility of splashing.

The color of the flame for the compound sodium hydroxide, NaOH is yellow-orange due to sodium metal.

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Answer:

strontium, magnesium, calcium, beryllium

Explanation:

these all belong to the same group!

Strontium , magnesium,calcium and beryllium have similar  properties as they belong to same group.

In the periodic table, properties vary along  a  group as well as period due to the change in number of valence electrons. In a group the number of valence electrons remains same for all the elements of a group .

A new successive shell is added and hence number of valence electrons remain same.Number of valence electrons do not change in a group and hence elements in a group have similar properties as only valence electrons take part in chemical reactions.

While in a period, with each successive element one more electron is added to the same shell due to which number of valence electrons for each shell does not remain same,rather it increases with each successive element .As a result, of this elements in a period do not have similar properties.

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Chemists use substances with distinct physical and chemical properties to separate mixtures into individual substances. These can be pure substances (a single element or compound) or mixtures containing multiple substances. The specific composition of each substance or mixture determines its properties.

The substances that chemists use to separate mixtures into individual substances generally have distinct physical and chemical properties. Each compound has a specific composition and demonstrates definitive properties that make them unique from other compounds. These properties include elements such as physical properties like hardness and boiling point, and chemical properties like flammability and acidity.

Substances, in the form of elements and compounds, can be combined in many ways to form different mixtures. A mixture, which is commonly encountered in nature, contains two or more substances physically combined. The relative composition of a mixture plays a key role in determining its properties.

Pure substances consist of only one type of element or compound, while mixtures contain multiple. Pure substances include elements that cannot be further broken down by chemical changes. The known elements are just over 100, with around 90 naturally occurring on earth.

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The Law of Conservation of Matter applies to chemical reactions by stating that the amount and type of atoms in the reactants must equal the amount and type in the products. This is due to the fact that matter cannot be created or destroyed in an isolated system. For example, the reaction of hydrogen and oxygen to form water shows this conservation.

The Law of Conservation of Matter states that matter cannot be created or destroyed in an isolated system. In the context of chemical reactions, this means that the amount and type of atoms before the reaction (in the reactants) must be equal to the amount and type of atoms after the reaction (in the products).

For example, in the reaction of hydrogen and oxygen to form water: 2H2 + O2 -> 2H2O, there are 4 hydrogen atoms and 2 oxygen atoms both before and after the reaction. Thus, the total mass of the reactants equals the total mass of the products, illustrating the Law of Conservation of Matter.

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