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3 years ago

Why do historians analyze historical events and cause and effect relationship

2 answers:

8 0

Recognizing patterns of cause and effect is an important analytical skill that allows historians to explain why things happened the way they did in the past. It's also a strategy that can make it possible to predict what may happen in the future.

Arte-miy333 [17]3 years ago

7 0

Answer:

yeah. def

Explanation:

becuase someone told me to

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Please answer this question

vova2212 [387]

Answer:

Yes

Explanation:

Natural gas is colorless and odorless, and explosive, so a sulfur-smell (similar to rotten eggs) is usually added for early detection of leaks. ... Natural gas is a fossil fuel. Natural gas is a non-renewable hydrocarbon used as a source of energy for heating, cooking, and electricity generation.

5 0

2 years ago

For Na2HPO4:(( (Note that for H3PO4, ka1= 6.9x10-3, ka2 = 6.4x10-8, ka3 = 4.8x10-13 ) a) The active anion is H2PO4- b) The activ

Komok [63]

Answer:

Check the explanation

Explanation:

Answer – Given, $H_3PO_4$ acid and there are three Ka values

$K_{a1}=6.9x10^8, K_{a2} = 6.2X10^8, and K_{a3}=4.8X10^{13}$

The transformation of $H_2PO_4- (aq) to HPO_4^2-(aq)$ is the second dissociation, so we need to use the Ka2 = 6.2x10-8 in the Henderson-Hasselbalch equation.

Mass of KH2PO4 = 22.0 g , mass of Na2HPO4 = 32.0 g , volume = 1.00 L

First we need to calculate moles of each

Moles of KH2PO4 = 22.0 g / 136.08 g.mol-1

= 0.162 moles

Moles of Na2HPO4 = 32.0 g /141.96 g.mol-1

= 0.225 moles

[H2PO4-] = 0.162 moles / 1.00 L = 0.162 M

[HPO42-] = 0.225 moles / 1.00 L = 0.225 M

Now we need to calculate the pKa2

pKa2 = -log Ka

= -log 6.2x10-8

= 7.21

We know Henderson-Hasselbalch equation

pH = pKa + log [conjugate base] / [acid]

pH = 7.21 + log 0.225 / 0.162

= 7.35

The pH of a buffer solution obtained by dissolving 22.0 g of KH2PO4 and 32.0 g of Na2HPO4 in water and then diluting to 1.00 L is 7.35

6 0

3 years ago

What will increased temperature in a reaction cause

uranmaximum [27]

I think your answer is 2 because the temperature will rise so the particles will move faster

7 0

3 years ago

El compuesto es soluble en agua y conduce la eletricidad

salantis [7]

Answer:

creo que si

Explanation:

por que si vienes a ver has un experimento con agua y electricidad. por eso es que el compuesto es soluble en agua y conduce la electricidad

6 0

2 years ago

Which of the following statements is (are) true about enzyme-catalyzed reactions? a. The reaction is faster than the same reacti

Brums [2.3K]

Answer : The correct option is A.

Explanation :

Enzyme-catalyzed reaction :

Enzyme act as a biological catalyst and the role of catalyst is to increase the rate of chemical reaction by lowering the activation energy.

Most of the chemical reactions are slow in the absence of enzyme but in the presence of enzyme, the reaction become faster. That means the Enzyme accelerate the rate of reaction.

Therefore, the correct answer is the reaction is faster than the same reaction in the absence of the enzyme.

5 0

2 years ago