What is a scanning tunneling microscope?

500.0 mL of a gas is collected at 745.0 mmHg. What will the<br> volume be at 760 mmHg?

Natalija [7]

Answer:

490 ml

Explanation:

5 0

3 years ago

How many mL are in 5.000 L

Aleks [24]

Answer:

Start off and multiply the volume value by 1000,

so that would mean

5000 x 1000

= 5,000,000 mL

3 0

3 years ago

The change in enthalpy for the reaction A - P is x kJ/mol. What does the enthalpy change for the reaction P -A? (A) -x kJ/mol (B

nikdorinn [45]

Answer : The correct option is, (A) -x kJ/mol

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.

According to this law, the chemical equation can be treated as ordinary algebraic expression and can be added or subtracted to yield the required equation. That means the enthalpy change of the overall reaction is the sum of the enthalpy changes of the intermediate reactions.

The given chemical reaction is,

$A\rightarrow P$ $\Delta H=x\text{ kJ/mole}$

Now we have to determine the value of $\Delta H$ for the following reaction i.e,

$P\rightarrow A$ $\Delta H'=?$

According to the Hess’s law, if we reverse the reaction then the sign of $\Delta H$ change.

So, the value $\Delta H'$ for the reaction will be:

$\Delta H'=-(x\text{ kJ/mole})$

$\Delta H'=-x\text{ kJ/mole}$

Hence, the value of $\Delta H$ for the reaction is -x kJ/mole.

3 0

3 years ago

What causes the electrons to move and form static electricty?

Anettt [7]

Answer:

Static electricity is the result of an imbalance between negative and positive charges in an object. ... When two materials are in contact, electrons may move from one material to the other, which leaves an excess of positive charge on one material, and an equal negative charge on the other.

4 0

3 years ago

Calculate the mass of magnesium oxide produced when 0.645 g of magnesium hydroxide is the is completely decomposed.

FrozenT [24]

Answer:

0.44g

Explanation:

Given parameters:

Mass of magnesium hydroxide = 0.645g

Solution

The balanced reaction equation is shown below:

Mg(OH)₂ → MgO + H₂O

From the equation above, we see that the number of atoms are conserved.

To find the mass of magnesium oxide produced, we find the number moles of the decomposed magnesium hydroxide first:

Molar mass of Mg(OH)₂ = 24 + 2(16+1) = 58g/mol

Number of moles of Mg(OH)₂ = $\frac{mass}{molar mass}$

= $\frac{0.645}{58}$

= 0.011mole

Now, from the balanced equaiton, we know that:

1 mole of Mg(OH)₂ produces 1 mole of MgO

Therefore, 0.011mole of Mg(OH)₂ will produce 0.011mole of MgO

so mass of MgO = number of moles of MgO x molar mass of MgO

Molar mass of MgO = 24 + 16 = 40g/mol

mass of MgO = 0.011 x 40 = 0.44g

8 0

3 years ago