Which of the following liquids has the lowest viscosity?

What is reason for changing season of the earth

Vlad1618 [11]

Answer:

the reasons for the changes in seasons are: revolution of the Earth

The tilt of the Earth's axis

6 0

2 years ago

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A first-order reaction has a half-life of 20.0 minutes. Starting with 1.00 × 1020 molecules of reactant at time t = 0, how many

zalisa [80]

Half-life time of a reaction is time at which reactant concentration becomes half of its initial value.

Half-life of the first order reaction is 20 min. Rate constant can be calculated as follows:

$K=\frac{0.6932}{t_{1/2}}=\frac{0.6932}{20 min}=0.03466 min^{-1}$

The rate expression for first order reaction is as follows:

$k=\frac{2.303}{t}log\frac{A_{0}}{A_{t}}$

initial number of molecules of reactant are $10^{20}$ , time is 100 min thus, putting the values to calculate number of reactant at time 100 min,

$0.03466 min^{-1}=\frac{2.303}{100 min}log\frac{[10^{20}]}{A_{t}}$

On rearranging,

$\frac{10^{20}}{A_{t}}=31.988$

Or,

$A_{t}=3.13\times 10^{18}$

Therefore, number of molecules unreacted will be $3.13\times 10^{18}$

7 0

3 years ago

Please help!!

ludmilkaskok [199]

Answer:

yes, the law of conservation of mass hold true in this case burning magnesium strip is explained by this equation 2 Mg (s) + O2 (g) -> MgO (s)So the lighter magnesium, after reacting with oxygen in air, forms the heavier magnesium oxide. molar mass of magnesium and magnesium oxide are 24g and 40g respectively. So the same ratio 24:40 (i.e. 3:5) is maintained in the given masses of 48g and 80g, which means mass is conserved in the reacion.

Explanation:

Brainiest Please!!!

8 0

3 years ago

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If the compound below containing three types of alcohols were exposed to only 1 equivalent of hcl, what major product would you

sergey [27]

The question is incomplete. The image showing the compound and the options in the questions is attached.

Answer:

B

Explanation:

If we closely examine the structure of the compound given in the question, we will notice that the reaction must involve the substitution of the hydroxyl group by chlorine in the parent molecule.

This occurs when the -OH group combines with H^+ to form -OH2^+ which is a good leaving group.

Compound B is formed because, when -OH2^+ leaves, a carbocation is created. This carbocation is stabilized by the alkyl groups attached to the carbon atom bearing the leaving group by +I inductive effect. This carbon atom bearing the leaving group is a tertiary carbon atom thus it forms a more stable carbocation. Hence the product formed.

7 0

3 years ago

A 50.0 mL solution of 0.141 M KOH is titrated with 0.282 M HCl . Calculate the pH of the solution after the addition of each of

Kobotan [32]

Answer:

pH =1 2.84

Explanation:

First we have to start with the reaction between HCl and KOH:

$HCl~+~KOH->~H_2O~+~KCl$

Now for example, we can use a volume of 10 mL of HCl. So, we can calculate the moles using the molarity equation:

$M=\frac{mol}{L}$

We know that $10mL=0.01L$ and we have the concentration of the HCl $0.282M$ , when we plug the values into the equation we got:

$0.282M=\frac{mol}{0.01L}$

$mol=0.282*0.01$

$mol=0.00282$

We can do the same for the KOH values ( $50mL=0.05L$ and $0.141M$ ).

$0.141M=\frac{mol}{0.05L}$

$mol=0.141*0.05$

$mol=0.00705$

So, we have so far 0.00282 mol of HCl and 0.00705 mol of KOH. If we check the reaction we have a molar ratio 1:1, therefore if we have 0.00282 mol of HCl we will need 0.00282 mol of KOH, so we will have an excess of KOH. This excess can be calculated if we substract the amount of moles:

$0.00705-0.00282=0.00423mol~of~KOH$

Now, if we want to calculate the pH value we will need a concentration, in this case KOH is in excess, so we have to calculate the concentration of KOH. For this, we already have the moles of KOH that remains left, now we need the total volume:

$Total~volume=50mL+10mL=60mL$