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3 years ago

Helpppp, this is due at 12:00 am !!!!

Chemistry

1 answer:

OlgaM077 [116]3 years ago

3 0

Answer:

The individual substances in a mixture can be separated using different methods, depending on the type of mixture. These methods include filtration, evaporation, distillation and chromatography.

Explanation:

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Weight is constant every place in the universe <br> true or false

Savatey [412]

That is false. Weight is not constant every place in the universe. Take space for example. It all depends on gravity. So, the answer is false.

6 0

3 years ago

Read 2 more answers

The Henderson-Hasselbalch equation relates the pH of a buffer solution to the pKa of its conjugate acid and the ratio of the con

Kobotan [32]

Answer:

The correct answer is 190.5 mL of 1.00 M KH₂PO₄

Explanation:

A phosphate buffer is composed by phosphate acid (KH₂PO₄) and its conjugated base (K₂HPO₄). To obtain the relation between the concentrations of base and acid to add, we use Henderson-Hasselbach equation:

pH= pKa + log $\frac{base}{acid}$

We have: pH= 6.97 and pKa= 7.21. So, we replace the values in the equation:

6.97= 7.21 + log $\frac{base}{acid}$

6.97-7.21= log $\frac{base}{acid}$

-0.24= log $\frac{base}{acid}$

$10^{-0.24}$ = $\frac{base}{acid}$

0.575 = $\frac{base}{acid}$

$\frac{0.575}{1}$ = $\frac{base}{acid}$

It means that you have to mix a volume 0.575 times of conjugated base and 1 volume of acid. If we assume a total buffer concentration of 1 M, we have:

base + acid = 1

base= 1 - acid

We replace in the previous equation:

0.575= $\frac{1-acid}{acid}$

0.575 acid= 1 - acid

0.575 acid + 1 acid= 1

1.575 acid = 1

acid= 1/1,575

acid= 0.635

base= 1 - acid = 1 - 0.635 = 0.365

For a total volume of 300 ml, the volumes of both acid and base will be:

300 ml x 0.635 M = 190.5 ml of acid (KH₂PO₄)

300 ml x 0.365 M= 109.5 ml of base (K₂HPO₄)

We can corroborate our calculations as follows:

190.5 ml + 109.5 ml = 300 ml

109.5 ml / 190.5 ml = 0.575

4 0

3 years ago

Which of the following correctly

goblinko [34]

Answer:

An element is made of one type of atom, while a compound is two or

more types of atoms combined.

Explanation:

An element is a distinct substance that cannot be split up into simpler substances. Elements are substances that consists of only one kind of atom.

Compounds are substances composed of two or more kinds of atoms/elements joined together in a definite grouping.

There are over a hundred elements known to date.
Each one of the elements is symbolized by a capital or a capital letter followed by a small letter derived from English, Latin or Greek
Examples are copper, gold, iron
The properties of a compound are distinct and different from those of the individual elements that are combined in its make up.
There are several millions of compounds known.
They are usually represented by chemical formulae.

As we can see, compounds are indeed made up of more than one types of atoms whereas an element is made up of just one single atom.

8 0

4 years ago

How would you expect this object to behave if it starts out not moving? (The object is the circle, and the arrows show forces ac

Anika [276]

Answer:

I am 100% sure that it is A, speeding up and moving to the left

Explanation:

I took the test and got 100%.

Hope this helps!

3 0

3 years ago

Read 2 more answers

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

2 years ago