The element magnesium is a

True or false; when something heats up, New energy is created, and when something cool down, Energy is destroyed.

Ann [662]

Answer:

This is false.

Explanation:

This statement directly opposes the first law of thermodynamics which states that energy can neither be created nor destroyed, but can transfer from one source to another.

4 0

3 years ago

Dorothy left a frozen juice pop out on the counter. When she returned, the juice pop had melted into a liquid. Which of the foll

Brums [2.3K]

Answer:

B) The molecules were closer together when the juice pop was frozen.

8 0

3 years ago

My professor gave me two questions to solve using the Van Der Waals Equation. She told us to solve for P and the second one we h

Fed [463]

Answer:

P=atm

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

Explanation:

The problem give you the Van Der Waals equation:

$(P+\frac{n^{2}a}{V^{2}})(V-nb)=nRT$

First we are going to solve for P:

$(P+\frac{n^{2}a}{V^{2}})=\frac{nRT}{(V-nb)}$

$P=\frac{nRT}{(V-nb)}-\frac{n^{2}a}{v^{2}}$

Then you should know all the units of each term of the equation, that is:

$P=atm$

$n=mol$

$R=\frac{L.atm}{mol.K}$

$a=atm\frac{L^{2}}{mol^{2}}$

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

$T=K$

$V=L$

where atm=atmosphere, L=litters, K=kelvin

Now, you should replace the units in the equation for each value:

$P=\frac{(mol)(\frac{L.atm}{mol.K})(K)}{L-(mol)(\frac{L}{mol})}-\frac{(mol^{2})(\frac{atm.L^{2}}{mol^{2}})}{L^{2}}$

Then you should multiply and eliminate the same units which they are dividing each other (Please see the photo below), so you have:

$P=\frac{L.atm}{L-L}-atm$

Then operate the fraction subtraction:

P= $P=\frac{L.atm-L.atm}{L}$

$P=\frac{L.atm}{L}$

And finally you can find the answer:

P=atm

Now solving for b:

$(P+\frac{n^{2}a}{V^{2}})(V-nb)=nRT$

$(V-nb)=\frac{nRT}{(P+\frac{n^{2}a}{V^{2}})}$

$nb=V-\frac{nRT}{(P+\frac{n^{2}a}{V^{2}})}$

$b=\frac{V-\frac{nRT}{(P+\frac{n^{2}a}{V^{2}})}}{n}$

Replacing units:

$b=\frac{L-\frac{(mol).(\frac{L.atm}{mol.K}).K}{(atm+\frac{mol^{2}.\frac{atm.L^{2}}{mol^{2}}}{L^{2}})}}{mol}$

Multiplying and dividing units,(please see the second photo below), we have:

$b=\frac{L-\frac{L.atm}{atm}}{mol}$

$b=\frac{L-L}{mol}$

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

7 0

3 years ago

Draw a Lewis structure for [H3O]+. Show all unshared pairs and the formal charges, if any.

Montano1993 [528]

Answer: Formal Charges: Hydrogen = 0 and Oxygen = +1

Unshared Pair of electrons: Hydrogen = 0 and Oxygen = 2

Explanation:

The attachment below shows the Lewis structure and the calculations

3 0

3 years ago

What mass of sodium chloride (NaCl) forms when 7.5 g of sodium carbonate (Na2CO3) reacts with a dilute solution of hydrochloric

Gre4nikov [31]

The mass of NaCl formed is 8.307 grams

<u><em> calculation</em></u>

step 1: write the equation for reaction

Na₂CO₃ + 2HCl → 2 NaCl +CO₂ +H₂O

Step 2: find the moles of Na₂CO₃

moles = mass/molar mass

The molar mass of Na₂CO₃ is = (23 x2) + 12 + ( 16 x3) = 106 g/mol

moles = 7.5 g/106 g/mol =0.071 moles

Step 3: use the mole ratio to determine the mole of NaCl

Na₂CO₃:NaCl is 1:2 therefore the moles of NaCl =0.07 x2 =0.142 moles

Step 4: calculate mass of NaCl

mass= moles x molar mass

the molar mass of NaCl= 23 +35.5 =58.5 g/mol

mass = 0.142 moles x 58.5 g/mol =8.307 grams

8 0

3 years ago

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