Help plzzzz only the answer

Magnesium burns in air with a dazzling brilliance to produce magnesium oxide: 2 Mg(s) + O2(g) → 2 MgO(s) How many moles of O2 ar

TEA [102]

Answer:

1.05 mols of O2 gas

Explanation:

For this type of problem, it's important to understand what the balanced Chemical equation tells us:

<h3><u>Balanced Chemical equations</u></h3>

Let's look at the balanced chemical equation:

$2Mg(s)+O_2(g)-- > 2MgO(s)$

This equation two sides of the reaction arrow. On the left are the reactants (things you start with, and that react during the chemical reaction), and on the right side are products (things that are produced during the chemical reaction that you end with).

The numbers in front of each compound tell how many of molecules are involved for a full reaction without anything left over. A "mol" is a large quantity ( $6.022*10^{23}$ ), in this case, of molecules , since it's unlikely you're only taking a single molecule of each substance (it would be so tiny, you wouldn't even know you were doing the reaction).

So,for every 2 moles of Magnesium used, we'll also need 1 mole of Oxygen, and it will produce 2 moles of Magnesium Oxide.

In a way, during the reaction it's almost like 2 moles of Magnesium is equal to 1 mole of Oxygen and is equal to 2 moles of Magnesium Oxide:

$2 mol Mg(s)=1mol O_2(g)=2molMgO(s)$

From here, we can build some unit ratios, to convert between the known quantity of moles we have, and find the unknown quantity of moles that are requested.

<h3><u>Finding the right unit ratio</u></h3>

We know that we are looking at 2.10 mol of Magnesium, so we want a unit ratio with moles of Mg on the bottom. <u>We want to find moles of O2</u>, <u>so we want a unit ratio of moles of O2 on top</u>.

The unit ratio we want is the middle part of the equation, divided by the left part of the equation.

$2 mol Mg(s)=1mol O_2(g)\\\frac{2 mol Mg(s)}{2 mol Mg(s)}=\frac{1mol O_2(g)}{2 mol Mg(s)}\\1=\frac{1mol O_2(g)}{2 mol Mg(s)}$

Since this quantity is 1, it is a unit ratio and can be multiplied to other things to change their units (for this problem).

<h3><u>Finding the answer</u></h3>

Starting with what we know, and multiplying by our unit ratio:

$2.10 mol Mg(s)*\frac{1mol O_2(g)}{2 mol Mg(s)}=1.05mol O_2(g)$

Notice that the units from the first quantity cancel with the units on the bottom of the fraction, leaving only the unit on top of the fraction ... the exact units we wanted!

So, 1.05mols of O2 would be consumed during the reaction if exactly 2.10moles of Magnesium are burned.

4 0

3 years ago

Under what pressure will a scientist need to store 0.400 miles of gas if the container has a volume of 200.0 mL and the temperat

mihalych1998 [28]

Hello!

Ok so for this problem we use the ideal gas law of PV=nRT and I take it that the scientist needs to store 0.400 moles of gas and not miles.

So if we have
n=0.400mol
V=0.200L
T= 23degC= 273k+23c=296k
R=ideal gas constant= 0.0821 L*atm/mol*k

So now we rearrange equation for pressure(P)

P=nRT/V
P=((0.400mol)*(0.0821 L*atm/mol*k)*(296k))/(0.200L) = 48.6 atm of pressure

Hope this helps you understand the concept and how to solve yourself in the future!! Any questions, please feel free to ask!! Thank you kindly!!!

4 0

3 years ago

Grams smallest to kilograms and milligrams

Anna007 [38]

Grams is smaller than kilograms but larger than milligrams

1g = 0.001 kg
1g = 1000 mg

Grams is an SI unit for mass.

International System of Units (SI Units) are organized body of measurements for physical quantity. They are set to be the norm or global norm scaling for every physical quantity which includes kilogram, meter, second, ampere, kelvin, candela and mole. These measurements then can increase or decrease by the power of ten, multiplied or divided. As said and explained, the SI is helpful in describing objects because
<span>1. They give us the idea of how much matter is contained in that single substance or the current state the matter is in or how hot or cold. We measure and can quantify the quality of the specific matter.</span> <span><span>
2. </span>SI Units are a global set of measurement hence, we can communicate with ease from western to eastern countries with these measurements without having problems in terms of portraying or displaying a set of physical quantities.</span><span> </span>

4 0

3 years ago

Why is the equation 4Al+302>2Al203 balanced

cestrela7 [59]

Answer:

It's coefficient to the front of each element that requires it.

Explanation:

It is coefficient to the front of each element or compound that requires it. Essentially you are multiplying the amount of atoms or compounds on one side to match the amount on the other side.

8 0

3 years ago

What is the percent yield of NaCl if 31.0 g of CuCl2 reacts with excess NaNO3 to produce 21.2 g of NaCl?

Harrizon [31]

First you need to find the balanced chemical formula.
CuCl₂+2NaNO₃→2NaCl+Cu(NO₃)₂

Then you can find out how much NaCl 31.0g of CuCl₂ should produce using stoichiometry. Divide 31.0g by the molar mass of CuCl₂ (134.446g/mol) to get 0.2306mol CuCl₂. Than multiply 0.2306mol CuCl₂ by 2 to get 0.4612mol NaCl. Than multiply 0.4612mol by the molar mass of NaCl (58.45g/mol) to get 26.95g of NaCl.
that means that 100% yield would give you 26.95g of NaCl so to find percent yield divide 21.2 by 26.95 to get 0.7867 which is 78.7% yield

Therefore the answer is 78.7% yield.
I hope this helps. Let me know if anything is unclear

3 0

3 years ago