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3 years ago

Describe, in terms of electrons, the difference between a calcium atom and a calcium ion

1 answer:

3 0

The Calcium atom has 2 valence electrons but a Calcium ion will have no electrons because it is a cation ion. Meaning that there are more protons than electrons. Also, the normal calcium symbol is Ca but the calcium ion is Ca²⁺

I hope this wasn't too late

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How many milliliters o a suspension base must be mixed with 250 mL o a paroxetine (PAXIL) oral suspension, 10 mg/5 mL, to change

Maksim231197 [3]

Answer : The suspension base added will be, 250 mL

Explanation :

As we are given that the initial concentration of solution is, 10 mg/5mL or we can say that 2 mg/mL.

Volume of solution = 250 mL

First we have to determine the mass of PAXIL.

As, 1 mL of solution contain mass of PAXIL = 2 mg

So, 250 mL of solution contain mass of PAXIL = $250\times 2=500mg$

Now we have to determine the final solution required.

As we are given the final concentration of solution is, 0.1 % w/v that means 0.1 g in 100 mL of solution.

Concentration of solution = $\frac{0.1g}{100mL}=\frac{0.1\times 1000mg}{100mL}=\frac{100mg}{100mL}=\frac{1mg}{mL}$

Let the 'x' mL of the suspension base is added. So, the ratio of mass and volume will be:

$\frac{500mg}{(x+250)mL}=\frac{1mg}{1mL}$

$x=250mL$

Thus, the suspension base added will be, 250 mL

4 0

3 years ago

Convert the following<br> 4. 100 cm =<br> 5. 453 m = _<br> 6. 89847nm = _<br> 7. 3Mm =

fredd [130]

4. I meter
5. 0.453 kilometers
6. 89.84700 microns
7. Yo momma

6 0

3 years ago

Given that H 2 ( g ) + F 2 ( g ) ⟶ 2 HF ( g ) Δ H ∘ rxn = − 546.6 kJ ⋅ mol − 1 2 H 2 ( g ) + O 2 ( g ) ⟶ 2 H 2 O ( l ) Δ H ∘ rxn

andre [41]

Answer : The enthalpy of reaction is, -521.6 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 main chemical reaction is,

$2F_2(g)+2H_2O(l)\rightarrow 4HF(g)+O2(g)$ $\Delta H=?$

The intermediate balanced chemical reaction will be,

(1) $H_2(g)+F_2(g)\rightarrow 2HF(g)$ $\Delta H_1=-546.6kJ/mol$

(2) $2H_2(g)+O_2(g)\rightarrow 2H_2O(l)$ $\Delta H_2=-571.6kJ/mol$

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

(1) $2H_2(g)+2F_2(g)\rightarrow 4HF(g)$ $\Delta H_1=2\times (-546.6kJ/mol)=-1093.2kJ/mol$

(2) $2H_2O(l)\rightarrow 2H_2(g)+O_2(g)$ $\Delta H_2=+571.6kJ/mol$

The expression for enthalpy of main reaction is,

$\Delta H=\Delta H_1+\Delta H_2$

$\Delta H=(-1093.2)+(571.6)$

$\Delta H=-521.6kJ/mol$

Therefore, the enthalpy of reaction is, -521.6 kJ/mol

4 0

3 years ago

Where would you expect to find carbon

gizmo_the_mogwai [7]

You can find carbon by itself or with other naturally occurring compounds, in all organic compounds (carbohydrates and nucleic acids), and in every living thing

5 0

4 years ago

What mass of oxygen will react with 10.5g of ethane according to the following reaction?

Artyom0805 [142]

For every question, you simply have to use the molar ratio method.

First find the mole of one substance using the formula, Moles=Mass/Mr.

Now compare them and find the moles of the substance whose mass you need using molar ratio. Use the formula written above to find the theoretical Mass required for reaction.

7 0

3 years ago

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