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3 years ago

Which element is a liquid at 1000 k 1.Ag 2.Al 3.Ca 4.Ni

2 answers:

7 0

in these options not any Element are liquid at 1000k i think you type wrong in first option It is Hg not Ag and Hg is liquid at 1000 k

-Dominant- [34]3 years ago

6 0

<u>Answer:</u> The correct answer is Option 2.

<u>Explanation:</u>

All the given elements are considered as metals because they all are solid at room temperature and solids are generally solid at room temperatures.

For a solid to change into liquid, it has to attain a minimum temperature known as melting point of that solid.

The melting point of the given elements are:

Silver (Ag) = 1235 K

Aluminium (Al) = 933.5 K

Calcium (Ca) = 1115 K

Nickel )Ni) = 1728 K

From the above melting points, the element which will turn into liquid below 1000 K will be aluminium.

Hence, the correct answer is Option 2.

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Nata [24]

Answer:

it says the answer is variation

6 0

2 years ago

Read 2 more answers

The radioactive isotope of lead, Pb-209, decays at a rate proportional to the amount present at time t and has a half-life of 3.

Marina86 [1]

Answer:

Therefore it will take 7.66 hours for 80% of the lead decay.

Explanation:

The differential equation for decay is

$\frac{dA}{dt}= kA$

$\Rightarrow \frac{dA}{A}=kdt$

Integrating both sides

ln A= kt+c₁

$\Rightarrow A= e^{kt+c_1}$

$\Rightarrow A=Ce^{kt}$ [ $e^{c_1}=C$ ]

The initial condition is A(0)= A₀,

$\therefore A_0=Ce^{0.k}$

$\Rightarrow C=A_0$

$\therefore A=A_0e^{kt}$ .........(1)

Given that the $Pb_{209}$ has half life of 3.3 hours.

For half life $A=\frac12 A_0$ putting this in equation (1)

$\frac12A_0=A_0e^{k\times3.3}$

$\Rightarrow ln(\frac12)= 3.3k$ [taking ln both sides, $ln \ e^a=a$ ]

$\Rightarrow k=\frac{ln \frac12}{3.3}$

⇒k= - 0.21

Now A₀= 1 gram, 80%=0.8

and A= (1-0.8)A₀ = (0.2×1) gram = 0.2 gram

Now putting the value of k,A and A₀in the equation (1)

$\therefore 0.2=1e^{(-0.21)\times t}$

$\Rightarrow e^{-0.21t}=0.2$

$\Rightarrow -0.21t= ln(0. 2)$

$\Rightarrow t= \frac{ln (0.2)}{-0.21}$

⇒ t≈7.66

Therefore it will take 7.66 hours for 80% of the lead decay.

3 0

2 years ago

Calculate the molar mass of CH4 gas at STP when 5.46Lof the gas weighs 4g??

meriva

Answer:

About 16.42 grams

Explanation:

$PV=nRT \\\\(1)(5.46L)=n(0.0821)(273) \\\\n\approx 0.2436 \\\\4g/0.2436\approx 16.42$

Hope this helps!

6 0

3 years ago

Will calcium metal react with chromium (III) chloride? Explain your answer

iren [92.7K]

Calcium metal with chromium(III) chloride would react. Calcium metal is more reactive than chromium metal; therefore, putting calcium metal in chromium chloride would create a reaction, where as putting chromium metal in calcium chloride would not form any reaction.

5 0

2 years ago

When maganese dioxide is added to hydrogen chloride you get water maganese dichloride and chlorine gas write the balanved equati

babunello [35]

Answer: When maganese dioxide is added to hydrogen chloride you get water maganese dichloride and chlorine gas then balanced equation is $MnO_{2} + 4HCl \rightarrow 2H_{2}O + MnCl_{2} + Cl_{2}$ .

Explanation:

The word equation is given as maganese dioxide is added to hydrogen chloride you get water maganese dichloride and chlorine gas.

Now, in terms of chemical formulae this reaction equation will be as follows.

$MnO_{2} + HCl \rightarrow H_{2}O + MnCl_{2} + Cl_{2}$

Here, number of atoms on reactant side are as follows.

Mn = 1
O = 2
H = 1
Cl = 1

Number of atoms on product side are as follows.

Mn = 1
O = 1
H = 2
Cl = 4

To balance this equation, multiply HCl by 4 on reactant side and multiply $H_{2}O$ by 2 on product side. Therefore, the equation can be rewritten as follows.

$MnO_{2} + 4HCl \rightarrow 2H_{2}O + MnCl_{2} + Cl_{2}$

Hence, number of atoms on reactant side are as follows.

Mn = 1
O = 2
H = 4
Cl = 4

Number of atoms on product side are as follows.

Mn = 1
O = 2
H = 4
Cl = 4

Since, this equation contains same number of atoms on both reactant and product side. Therefore, this equation is now balanced equation.

Thus, we can conclude that when maganese dioxide is added to hydrogen chloride you get water maganese dichloride and chlorine gas then balanced equation is $MnO_{2} + 4HCl \rightarrow 2H_{2}O + MnCl_{2} + Cl_{2}$ .

6 0

3 years ago