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wolverine [178]

3 years ago

10

Calculate the following using the correct significant digits: 12.354 + 17.5?

1 answer:

Wittaler [7]3 years ago

3 0

Answer:

29.854

Explanation:

12+17=29

.354+.5= 854

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How many moles are in 5.25 L of oxygen gas as stp

Masteriza [31]

Answer:

The correct answer is 0, 235 mol

Explanation:

We use the formula PV =nRT. The normal conditions of temperature and pressure are 273K and 1 atm, we use the gas constant = 0, 082 l atm / K mol:

1 atm x 5, 25l = n x 0, 082 l atm / K mol x 273 K

n= 1 atm x 5, 25l /0, 082 l atm / K mol x 273 K

n= 0, 235 mol

8 0

2 years ago

What is the ph of a buffer prepared by adding 0.809 mol of the weak acid ha to 0.608 mol of naa in 2.00 l of solution? The disso

Anarel [89]

The pH of the buffer is 6.1236.

Explanation:

The strength of any acid solution can be obtained by determining their pH. Even the buffer solution strength of the weak acid can be determined using pH. As the dissociation constant is given, we can determine the pKa value as the negative log of dissociation constant value.

$pKa=-log[H] = - log [ 5.66 * 10^{-7}]\\ \\pka = 7 - log (5.66)=7-0.753=6.247\\\\pka = 6.247$

The pH of the buffer can be known as

$pH = pK_{a} + log[\frac{[A-]}{[HA]}}]$

The concentration of $[A^{-}] = Moles of [A]/Total volume = 0.608/2 = 0.304 M\\$

Similarly, the concentration of [HA] = $\frac{Moles of HA}{Total volume} = \frac{0.809}{2} = 0.404$

Then the pH of the buffer will be

pH = 6.247 + log [ 0.304/0.404]

$pH = 6.247 + log 0.304 - log 0.404=6.247-0.517+0.3936=6.1236$

So, the pH of the buffer is 6.1236.

5 0

3 years ago

Determine the empirical formula. a 3.880g sample contains 0.691g of magnesium , 1.84 g of sulfur , and 1.365 g of oxygen .

Aliun [14]

Answer:

Mg S2 O3

Explanation:

.691 g of Mg is .284 mole

1.84 g of S is .5739 mole

1.365 g of O is .8531 mole you can see the ratio is ~ 1 :2 :3

Mg S2 O3

4 0

2 years ago

In the reaction 4Al+3O2→_Al2O3 , what coefficient should be placed in front of the Al2 to balance the reaction?

nika2105 [10]

Sorry I came a lil late,

The answer to your question is, 2.

Hope this helps! :)

6 0

3 years ago

Read 2 more answers

Relative formula mass of glucose? (C6H12O6)

Rom4ik [11]

To find the mass of glucose, you must multiply the atomic weight of each of the elements in the molecule by the subscripts in the formula:

$C_{6}=6*(12.01g)=72.06g$

$H_{12}=12*(1.008g)=12.096g$

$O_{6}=6*(15.999g)=95.994g$

Then you add all of them together:

$72.06g+12.096g+95.994g=180.15g$

Therefore, the molar weight of glucose is 180.15 grams.

3 0

3 years ago