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3 years ago

1. What do the ice ages tell us about how Earth's climate has changed in the past?

Chemistry

1 answer:

Levart [38]3 years ago

3 0

Answer:

During ice ages, the most characteristic change to the planet has been the formation and spread large ice sheets and glaciers across much the Northern Hemisphere.

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If thermal energy (heat) must be added to a chemical reaction in order for the reaction to take place, the reaction is _________

Harlamova29_29 [7]

If thermal energy (heat) must be added to a chemical reaction in order for the reaction to take place, the reaction is endothermic.

7 0

3 years ago

Give regents and mechanism

Kryger [21]

Answer:

Reagents: 1) $BH_3$ 2) $H_2_O2$ , $OH^-$

Mechanism: Hydroboration

Explanation:

In this case, we have a hydration of alkenes reaction. But, in this example, we have an anti-Markovnikov reaction. In other words, the "OH" is added in the least substituted carbon. Therefore we have to choose an anti-Markovnikov reaction: "hydroboration".

The first step of this reaction is the addition of borane ( $BH_3$ ) to the double bond. Then in the second step, we have the deprotonation of the hydrogen peroxide, to obtain the peroxide anion. In the third step, the peroxide anion attacks the molecule produced in the first step to produce a complex compound in which we have a bond " $BH_2-O-OH$ ". In step number 4 we have the migration of the C-B bond to oxygen. Then in step number 5, we have the attack of $OH^-$ on the $O-BH_2$ to produce an alkoxide. Finally, the water molecule produce in step 2 will protonate the molecule to produce the alcohol.

See figure 1

I hope it helps!

4 0

4 years ago

a flask contains 2 gases. the first gas has a pressure of 0.76 atm and the second gas gas a pressure of 4,500 Pa. what is the to

Liula [17]

Answer:

The total pressure is 0,804 atm

Explanation:

We use Dalton's law according to which the sum of the partial pressures is equal to the total pressure of a gas mixture. We convert the pressure in Pascals to atmosphere (it can also be done in reverse):

101300Pa ----1 atm

4500Pa----x= (4500Pa x 1atm)/101300Pa= 0,044 atm

P total= p1 + p2= 0,76 atm + 0,044 atm=0,804 atm

4 0

3 years ago

Would you expect hydrogen chloride to be a gas, a liquid or a solid, at room temperature and pressure? Explain your answer

Vlada [557]

At room temperature hydrogen chloride is a colorless gas with a sharp or pungent odor. Under pressure or at temperatures below –85°C (-121°F), it is a clear liquid.

6 0

3 years ago

The bonds that link many water molecules together to form a water drop are _____ bonds.

Gelneren [198K]

The bonds found between water molecules are called:

Hydrogen bonds

which contribute to water having a high number of Van Der Waals forces.

Explanation:

A hydrogen bond is an electromagnetic attraction within polar molecules in which hydrogen is joined to a larger atom, such as oxygen or nitrogen. This is not a dividing of electrons, as in a covalent bond. Preferably, this is an attraction among the positive and negative poles of charged atoms.

7 0

3 years ago