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4 years ago

This is really hard help pls

Chemistry

1 answer:

deff fn [24]4 years ago

4 0

The answers are A. Pseudoscience is often based only on opinions; D. Pseudoscience often involves explanations of beliefs; E. Pseudoscience includes subjective ideas.

Explanation:

Pseudosciences comprises disciplines or theories that do not follow scientific standards but claim to be factual. This includes areas such as clairvoyance or astrology because this is not based on evidence but subjectivity. Indeed, the base of most pseudosciences are personal beliefs, opinions, or subjective ideas. Moreover, complex theories or methods are created to try to explain these beliefs, but because they do not follow scientific standards they are not considered as valid. In this context, options A, D, and E are correct.

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Someone please help i don’t have much time left

REY [17]

Answer: Energy of reactants = 30, Energy of products = 10

Exothermic

Activation energy for forward reaction is 10.

Explanation:

Exothermic reactions are defined as the reactions in which energy of the product is lesser than the energy of the reactants. The total energy is released in the form of heat and $\Delta H$ for the reaction comes out to be negative.

Energy of reactants = 30

Energy of products = 10

Thus as energy of the product < energy of the reactant, the reaction is exothermic.

Activation energy $(E_a)$ is the extra energy that must be supplied to reactants in order to cross the energy barrier and thus convert to products.

$E_a$ for forward reaction is (40-30) = 10.

6 0

3 years ago

C2H5OH(l) + 3O2(g) → 2CO2(g) + 3H2O(l), ΔH = –1.37 × 103 kJ For the combustion of ethyl alcohol as described in the above equati

babymother [125]

Answer:

The true statements are: I. The reaction is exothermic.

II. The enthalpy change would be different if gaseous water was produced.

Explanation:

The given chemical reaction: C₂H₅OH(l) + 3O₂(g) → 2CO₂(g) + 3H₂O(l), ΔH= -1.37×10³kJ

1. In an exothermic reaction, heat or energy is released from the system to the surrounding. Thus for an exothermic process the change in enthalpy is less than 0 or negative (ΔH < 0) .

Since the enthalpy change for a combustion reaction is negative. Therefore, the given reaction is exothermic.

2. The change in enthalpy (ΔH) of a reaction is equal to difference of the sum of standard enthalpy of formation (ΔHf°) of the products and the reactants.

ΔHr° = ∑ n.ΔHf°(products) − ∑ n.ΔHf°(reactants)

As the value of ΔHf° of water in gaseous state and liquid state is not the same.

Therefore, the enthalpy change of the reaction will be different, if gaseous water was present instead of liquid water.

3. An oxidation-reduction reaction or a redox reaction involves simultaneous reduction and oxidation processes.

The given chemical reaction, represents the combustion reaction of ethanol.

Since combustion reactions are redox reactions. Therefore, the given combustion reaction is an oxidation-reduction reaction.

4. According to the ideal gas equation: P.V =n.R.T

Volume (V) ∝ n (number of moles of gas)

Since the number of moles (n) of gaseous reactants is 3 and number of moles of gaseous (n) products is 2.

Therefore, the volume occupied by 3 moles of the reactant gaseous molecules will be more than 2 moles product gaseous molecules.

3 0

4 years ago

Ozone depleting chemicals are MOST

mina [271]

Ozone depleting chemicals are most likely belong to halogen group on the periodic table.

<h3>Ozone depleting chemicals are most likely to belong to which group on the periodic table?</h3>

Ozone depleting chemicals are the halogen group on the periodic table. Chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), halons, methyl bromide, carbon tetrachloride, hydrobromo-fluorocarbons and methyl chloroform. Fluorine, chlorine, bromine, iodine, astatine and tennessine are the elements of halogen group elements. These elements greatly affected the ozone layer.

So we can conclude that Ozone depleting chemicals are most likely belong to halogen group on the periodic table.

Learn more about ozone here: brainly.com/question/5019112

#SPJ1

3 0

2 years ago

If snails and crayfish die, what happens to the other species?

elixir [45]

Crayfish are very intolerant of pollution and other human-generated fouling of their environment. ... This abundance may be due more to the acid-generated absence of fish which prey on crayfish than to a direct, positive influence of the acid on the crayfish itself.

4 0

3 years ago

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the peak intensity of radiation for a particular star occurs at a wavelength of 2.0 nanometers and what spectral band is this

Dmitry_Shevchenko [17]

For a given peak intensity of radiation of a star that occurs at a wavelength of 2 nanometers, this is located at the spectral band of an X-ray. An X-ray's wavelength typically goes from 0.1 nano meters to 10 nano meters. Given that, the wavelength of the star fits perfectly into the range of an X-ray

6 0

3 years ago

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