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2 years ago

Water is densest at 4°C.

Chemistry

1 answer:

garik1379 [7]2 years ago

8 0

Answer:

About 277 Kelvin

Explanation:

Take the celcius, and add 273.15 to it

4°C + 273.15 = <u>277.15K</u>

And round the answer to the nearest whole

277.15K ≈ 277K

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67.029g to three significant figures

alexdok [17]

67.0 Should be th3 answer

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4 years ago

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1. What is the state of matter of each of these materials at room temperature? a) gold b) gasoline c) oxygen d) olive oil e) mer

ehidna [41]

Answer:

a) gold - Solid

b) gasoline - liquid

c) oxygen - gaseous

d) olive oil - liquid

e) mercury (found in thermometers) - liquid

f) aluminum - solid

Explanation:

Matter exists in three states viz: solid, gas and liquid. Note that, room temperature is a neither hot or cold temperature, which is about 20-23°C.

A) Gold is a transition metal with the symbol Au. At a room temperature, Gold, like most metals are found as SOLIDS.

B) Gasoline is a liquid mixture of refined hydrocarbons majorly used as fuels.

C) Oxygen is a chemical element with symbol O. It is a constituent of natural air, which is a mixture of different gases including oxygen. Hence, at room temperature, Oxygen is a gas.

D) Olive oil is a vegetable oil got from olives. It is composed of fats and it's a liquid at room temperature.

E) Mercury is an element with symbol Hg. It is the only metallic element found naturally (at room temperature) as a liquid. It is used in thermometers.

F) Aluminum is another chemical element with symbol Al. It is a lustrous metal that occurs as a Solid in room temperature.

8 0

3 years ago

Please answer quick!!

mestny [16]

Answer:

Explanation:

it causes the genes of two different individuals to mix

6 0

3 years ago

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Given these reactions, where X represents a generic metal or metalloid 1 ) H 2 ( g ) + 1 2 O 2 ( g ) ⟶ H 2 O ( g ) Δ H 1 = − 241

anygoal [31]

Answer : The enthalpy of the given reaction will be, -1048.6 kJ

Explanation :

According to Hess’s law of constant heat summation, the heat absorbed or evolved in a given chemical equation is the same whether the process occurs in one step or several steps.

The main reaction is:

$XCl_4(s)+2H_2O(l)\rightarrow XO_2(s)+4HCl(g)$ $\Delta H=?$

The intermediate balanced chemical reactions are:

(1) $H_2(g)+\frac{1}{2}O_2(g)\rightarrow H_2O(g)$ $\Delta H_1=-241.8kJ$

(2) $X(s)+2Cl_2(g)\rightarrow XCl_4(s)$ $\Delta H_2=+461.9kJ$

(3) $\frac{1}{2}H_2(g)+\frac{1}{2}Cl_2(g)\rightarrow HCl(g)$ $\Delta H_3=-92.3kJ$

(4) $X(s)+O_2(g)\rightarrow XO_2(s)$ $\Delta H_4=-789.1kJ$

(5) $H_2O(g)\rightarrow H_2O(l)$ $\Delta H_5=-44.0kJ$

Now reversing reaction 2, multiplying reaction 3 by 4, reversing reaction 1 and multiplying by 2, reversing reaction 5 and multiplying by 2 and then adding all the equations, we get :

(1) $2H_2O(g)\rightarrow 2H_2(g)+O_2(g)$ $\Delta H_1=2\times 241.8kJ=483.6kJ$

(2) $XCl_4(s)\rightarrow X(s)+2Cl_2(g)$ $\Delta H_2=-461.9kJ$

(3) $2H_2(g)+2Cl_2(g)\rightarrow 4HCl(g)$ $\Delta H_3=4\times -92.3kJ=-369.2kJ$

(4) $X(s)+O_2(g)\rightarrow XO_2(s)$ $\Delta H_4=-789.1kJ$

(5) $2H_2O(l)\rightarrow 2H_2O(g)$ $\Delta H_5=2\times 44.0kJ=88.0kJ$

The expression for enthalpy of main reaction will be:

$\Delta H=\Delta H_1+\Delta H_2+\Delta H_3+\Delta H_4+\Delta H_5$

$\Delta H=(483.6)+(-461.9)+(-369.2)+(-789.1)+(88.0)$

$\Delta H=-1048.6kJ$

Therefore, the enthalpy of the given reaction will be, -1048.6 kJ

4 0

3 years ago

How many moles of chloride ions are there in 2.5 L of 5 M magnesium chloride?

castortr0y [4]

Answer:

$n_{Cl^-}=25molCl^-$

Explanation:

Hello,

In this case, since the given 5-M concentration of magnesium chloride is expressed as:

$5\frac{molMgCl_2}{L}$

We can notice that one mole of salt contains two moles of chloride ions as the subscript of chlorine is two, in such a way, with the volume of solution we obtain the moles of chloride ions as shown below:

$n_{Cl^-}=5\frac{molMgCl_2}{L}*\frac{2molCl^-}{1molMgCl_2} *2.5L\\\\n_{Cl^-}=25molCl^-$

Best regards.

4 0

3 years ago