Our most recent mass extension happened about 65million years ago. Describe the effects of this event.

Answer:

The activation energy needed to form cubic diamond is much greater than the activation energy needed to form hexagonal diamond.

Explanation:

The activation energy refers to the minimum energy that reacting species must possess before they can undergo a particular chemical reaction.

This implies that if species do not possess the activation energy, they hardly undergo a given reaction. The activation energy is the barrier between reactants and products.

Hence, a reaction that has a very high activation energy occurs slowly or may not even occur. The activation energy needed to form cubic diamond is much greater than the activation energy needed to form hexagonal diamond hence the synthetic process produces hexagonal diamond and not the more thermodynamically stable cubic diamond.

Answer:

Light is absorbed, which produces characteristic lines.

Lines are dark on a visible light background.

Lines are produced by electrons being excited.

Explanation:

Edg

The characteristics of absorption spectra light is absorbed, which produces characteristic lines, lines are dark on a visible light background and Lines are produced by electrons being excited.

The term "absorption spectroscopy" applies to spectroscopic methods that assess how much radiation interacts with a sample and is absorbed as a proportion of frequency or wavelength. The sample takes in photons, meaning energy, from the emitting field.

The electron would be a subatomic particle with a negative one fundamental charge electric charge. Due to their lack of components or substructure, electrons, which have become part of the lepton particle family's first generation, could be typically regarded to be elementary particles.

The percentage of incoming electromagnetic energy that a material absorbs across a variety of frequencies is displayed in the material's absorption spectrum. In a way, an emission spectrum would be the converse of an absorption spectrum.

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Answer: The IUPAC name of [tex]CH_3COCH_3[/tex] propan-2-one and [tex]CH_3CH_2CH_2COCH_3[/tex] is pentan-2-one.

Explanation:

The basic rules for naming of organic compounds are :

1. First select the longest possible carbon chain. The longest possible carbon chain should include the carbons of double or triple bonds or functional group.For the number of carbon atom, we add prefix as 'meth' for 1, 'eth' for 2, 'prop' for 3, 'but' for 4, 'pent' for 5, 'hex' for 6, 'sept' for 7, 'oct' for 8, 'nona' for 9 and 'deca' for 10.

2. The naming of alkane is done by adding the suffix -ane, alkene by adding the suffix -ene, alkyne by adding the suffix -yne and ketones by adding the suffix -one.;

3. The numbering is done in such a way that the carbon containing the functional group gets the lowest number. While writing the name, the word root is given first , followed by the position of carbon containing the functional group followed by the suffix.

The IUPAC name of [tex]CH_3COCH_3[/tex] propan-2-one and [tex]CH_3CH_2CH_2COCH_3[/tex] is pentan-2-one.

Answer:

i-dk but A seems most logical to me

Explanation:

Answer:

A.

Explanation:

zinc and hydrochloric acid reacts to form zinc chloride and hydrogen.

hope it helps. :)

Answer:

Option E

Deuterium has one more neutron than hydrogen

Explanation:

Deuterium is an isotope of Hydrogen and hence there will variation in the number of neutron

Hydrogen has 0 neutron

Deuterium has 1 neutron and

Tritium has 2 neutron

Thus option E is correct

In the universe, there are approximately 26 deuterium atoms for every million hydrogen atoms. Deuterium has one more neutron than hydrogen.

The correct option is E.

Deuterium is a stable isotope of hydrogen, whose atomic weight is 2.014.

It is also called heavy hydrogen, and it contains one neutron and one proton.

In nuclear fusion reactors, deuterium is employed as a tracer, while in heavy water moderated fission reactors, it is utilized to slow down neutrons.

Thus, the correct option is E.

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The thermometers with red liquid usually depicts a kerosene based column with red dye. It is more safe than mercury thermometer. The red liquid inside the thermometer moves up due to the molecules of the liquid move faster and get a little further apart. The correct option is B.

The device which is used to measure the temperature is defined as the thermometer. It can measure the temperature of a solid such as food, a liquid like water and a gas like air.

The thermometers which are developed for clinical purposes are called clinical thermometers. It can also measure the temperature of human body. It is a long narrow glass tube which contain a bulb and consists of mercury at the end.

When a thermometer is heated, the molecules present in the liquid inside the thermometer get a little further apart. Because the liquid takes up more space. So the red line moves up in the tube.

Thus the correct option is B.

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Answer:

C

Explanation:

Perfume needs to evaporate in order to smell.  If this perfume didn't evaporate, it would stay as a liquid and never smell.  

It wouldn't be D, as no toxic perfumes is sold.

It's not A because perfume doesn't have to be pressurized in order to not evaporate.

It's not B, as it is a hasty conclusion to the claim.  Plus, if the perfume did have an odor, even while not evaporating, the sales would be low as the product is that good.  

Answer:

1.84

Explanation: just input the value into the formula pv=nrt

p*30=2*0.08206*337 then divide both sides by 30 and  get 1.84

Answer:

Explanation:

your not so smart

Explanation:

To find the number of moles in a substance given it's number of entities we use the formula

[tex]n = \frac{N}{L} \\[/tex]

where n is the number of moles

N is the number of entities

L is the Avogadro's constant which is

6.02 × 10²³ entities

We have

[tex]n = \frac{2.56 \times {10}^{13} }{6.02 \times {10}^{23} } \\ \\ \\ = 4.25 \times {10}^{ - 11} \: \: \: moles[/tex]

Hope this helps you

Answer:

14.91 mL

Explanation:

Assuming the weak acid is monoprotic, we can solve this problem using the equation:

Where subscript 1 stands for the Volume and Concentration of the weak acid, while 2 stands for those of NaOH.

We input the data:

And solve for V₂:

The volume of 0.1817 M NaOH has to be added to reach the equivalence point is 14.91 mL.

Volume for the given solution will be calculated from the below equation:

M₁V₁ = M₂V₂, where

M₁ = Molarity of weak acid = 0.1084 M

V₁ = volume of weak acid = 25 mL

M₂ = molarity of NaOH = 0.1817 M

V₂ = volume of NaOH = to find?

On putting all these values on the above equation and calculate for V₂ as:
V₂ = (0.1084)(25) / (0.1817) = 14.91 mL

Hence required volume is 14.91 mL.

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Answer:

78.14% Pb²⁺ and 21.86% of Cd²⁺

Explanation:

The first titration involves the reaction of both Pb²⁺ and Cd²⁺

In the second titration, as the buffer is HCN/NaCN, the Cd²⁺ precipitates as Cd(CN)₂ and the only ion that reacts is Pb²⁺

In the first titration:

Moles EDTA = Moles Pb²⁺ and Cd²⁺:

28.89mL = 0.02889L * (0.06950moles / L) = 2.008x10⁻³ moles in the aliquot. In the sample:

2.008x10⁻³ moles * (250.0mL / 50.0mL) =

0.01004 moles = Pb²⁺ + Cd²⁺ (1)

In the second titration:

19.07mL = 0.01907L * (0.06950mol / L) = 1.325x10⁻³ moles Pb²⁺ in the aliquot. In the sample:

1.325x10⁻³ moles Pb²⁺ * (250.0mL / 50.0mL) =

6.626x10⁻³ moles Pb²⁺

That means the moles of Cd²⁺ are:

0.01004 moles = Cd²⁺ + 6.626x10⁻³ moles Cd²⁺

3.413x10⁻³ moles Cd²⁺

The mass of each ion is:

Cd²⁺ -Molar mass: 112.411g/mol-:

3.413x10⁻³ moles Cd²⁺ * (112.411g / mol) =

0.384g of Cd²⁺

Pb²⁺ -Molar mass: 207.2g/mol-:

6.626x10⁻³ moles Pb²⁺ * (207.2g / mol) =

1.373g of Pb²⁺

The percent mass of each ion is:

1.373g Pb²⁺ / 1.757g = 78.14% Pb²⁺

And:

0.384g of Cd²⁺ / 1.757g * 100 = 21.86% of Cd²⁺

Answer:

c ammonium hydroxide nh4oh has higher ph value and its a base

plz mark me branliest

Answer:

c) ammonium hydroxide

Explanation:

ammonium hydroxide nh4oh has higher ph value, and it is an alkaline

Answer:

Kb=x^2/0.42-x (eqn to calculate)

basicity (pkb) 9.3

Explanation:

Answer:

b) The total moles of each element present in the reactants and in the products.

Explanation:

Hello there!

In this case, since the law of conservation of mass is used to realize that the mass, atoms and molecules of all the species involved in a chemical reaction must be the same at both reactants and products, we can see that a and c stand for those that must be equal; thus, we infer that the moles can be different as they stand for the amount of substance which is related to the mass via molar masses. Therefore, the answer would be b) The total moles of each element present in the reactants and in the products.

Regards!

Answer: [tex]\Delta G[/tex] for the reaction   is -90kJ

Explanation:

The balanced chemical reaction is,

[tex]2H_2S(g)+SO_2(g)\rightarrow 3S_{rhombic}(s)+2H_2O(g)[/tex]

The expression for Gibbs free energy change is,

[tex]\Delta G=[n\times G_{products}]-[n\times G_{reactants}][/tex]

Putting the values we get :

[tex]\Delta G=[3\times G_f{S,rhombic}+2\times G_f{H_2O}]-[2\times G_f{H_2S}+1\times G_f{SO_2}][/tex]

[tex]\Delta G=[(3\times 0kJ/mol)+(2\times -229kJ/mol)]-[(2\times -34kJ/mol) +(1\times -300kJ/mol)][/tex]

[tex]\Delta G=-90kJ[/tex]

Thus [tex]\Delta G[/tex] for the reaction[tex]2H_2S(g)+SO_2(g)\rightarrow 3S_{rhombic}(s)+2H_2O(g)[/tex]   is -90kJ

Answer:

The changes of state occur during distillation are boiling followed by condensation. The liquid is converted into its vapor phase at its boiling point and the vapor is then condensed back to liquid on cooling.

Explanation:

Heart me pls

Since pH + pOH = 14, given a pOH of 4.53, our pH would be 14 - 4.53 = 9.47. And since the pH is greater than 7, this solution is basic. So, the correct answer choice would be D.

Answer:

Rain is a liquid and hail is a solid.

Answer:

A Li2O

Explanation:

Li has a 1+ charge and O has a 2- charge so to balance the charges there needs to be 2 Li for every 1 O

The product forms from the synthesis reaction between lithium (Li)and oxygen (O) is Li₂O. The correct option is A.

Synthesis reaction is the reaction when two or more products combine to form a single product.

An example of a synthesis reaction is the combination of sodium (Na) and chlorine (Cl) to produce sodium chloride (NaCl).

Thus, the correct option is A. Li2O.

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Answer:

See explanation

Explanation:

If we look at the tests to be performed on the compounds carefully, we will notice that;

i) Addition of H2S with 0.2 M HCl produced a black solid. This black solid may result from the reaction;

H2S + Cu2+ ---->CuS(balck solid) + H2

or

H2S + Pb2+  ---->PbS(balck solid) + H2

Hence, Cu2+ or Pb2+  may be present

ii) Addition of (NH4)2S produced a white solid. This means that  K^+ may be present because the white precipitate is formed during metathesis.

iii) Potassium ion is known to burn with a purple flame.

Hence the suspected ions are;

Cu2+ , Pb2+ and  K^+

Element X Exists as diatomic molecules . In which group of the Periodic Table is X placed ?

Group VII

Group VII - elements are Fluorine , Chlorine , Bromine and Iodine .

They exist in diatomic molecules as F2 , Cl2 , Br2 and I2 .