Explain what is meant by Pleistocene ice age

1 answer:

7 0

By Pleistocene ice age is meant the glacial periods that appeared in the Pleistocene. The Pleistocene is the first epoch of the Quaternary. It is an epoch when there was a so called ''ice age'' on the Earth, or rather a glacial period. During this ice age the planet had much lower temperatures on a global scale. The climate was also much drier. Lot of ocean water was frozen in the ice sheets that were stretching deep into the North American and Eurasian continents, which resulted in much lower sea levels that today as well. The places further north than 40 degrees of latitude were almost exclusively covered with ice, so life was almost impossible apart from some coastline places.

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Which Statement correctly describes protons

____ [38]

Answer:

They have a positive charge and are present in the nucleus of an atom along with the neutrons.

explanation:

Protons have a positive charge.

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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.

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4 years ago

How many moles of NaCl must be dissolved in 0.5 L of water to make a 4 mole/L

kvv77 [185]

C = 4 mol/l
v = 0.5 l

n(NaCl)=cv

n(NaCl) = 4 mol/l · 0.5 l = 2 mol

2 moles of NaCl must be dissolved

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3 years ago

sound travels slower in colder air than it does in warmer air why does the speed of sound depend on air temperature

Marta_Voda [28]

Answer:

Explanation:

The speed of sound in the air mainly depends on temperature. At high altitudes, where it is much colder, sound travels slower. The higher the temperature, the faster the air molecules are moving to begin with, and the quicker they bump into each other as a sound wave passes through.

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3 years ago

Read 2 more answers

Calculate the boiling point of a solution of 500.0 g of ethylene glycol (c2h6o2) dissolved in 500.0 g of water. kf = 1.86Â°c/m a

Bingel [31]

Answer:The boiling point of the solution is 108° C.

Explanation:

Boiling point of pure water=T= $100^oC$