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stepladder [879]
1 year ago
7

Plsssssss! help! 20 points

Chemistry
1 answer:
Evgen [1.6K]1 year ago
5 0

Answer:

Explanation:

molecular weight of N₂H₄ is as follows

2 x 14 + 4 x 1 = 32

so 32 gram of N₂H₄  is equal to one mole of N₂H₄

25 gram of  N₂H₄ will be equal to 25 / 32 mole of  N₂H₄

so numerical quantity needed to convert grams of  N₂H₄  to mole is

1 / 32 or .03125 . This number needs to be multiplied with grams of N₂H₄

to convert it to number of moles.

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The ph of a solution that contains 0.818 m acetic acid (ka = 1.76 x 10-5) and 0.172 m sodium acetate is __________.
crimeas [40]
PH is calculated using <span>Handerson- Hasselbalch equation,

                                      pH  =  pKa  +  log [conjugate base] / [acid]

Conjugate Base  =  Acetate (CH</span>₃COO⁻)
Acid                    =  Acetic acid (CH₃COOH)
So,
                                      pH  =  pKa  +  log [acetate] / [acetic acid]

We are having conc. of acid and acetate but missing with pKa,
pKa is calculated as,

                                     pKa  =  -log Ka
Putting value of Ka,
                                     pKa  =  -log 1.76 × 10⁻⁵

                                     pKa  =  4.75
Now,
Putting all values in eq. 1,
                     
                                     pH  =  4.75 + log [0.172] / [0.818]

                                     pH  =  4.072
4 0
2 years ago
If 32.0 g of MgSO4⋅7H2O is thoroughly heated, what mass of anhydrous magnesium sulfate will remain?
Arada [10]
Find moles of MgSO4.7H2O

molar mass = 246
so moles  = 32 / 246  = 0.13 moles.

When heated, all 7 H2O from 1 molecule will be gone. 
total moles of H2O present = 7 x 0.13 = 0.91
mass of those H2O = 0.91 x 18  = 16.38g

so mass of anyhydrous MgSO4 remain = 32 - 16.38 = 15.62 g
6 0
1 year ago
What is the total number of sp2-hybridized carbon atoms present in the fluorophore used in the experiments
Mandarinka [93]

Answer:

9

Explanation:

The structure of fluorophore used in the experiments has been drawn in the attachment. And from the drawing counting we can say that there are 9 sp2-hybridized carbon atoms present. Fiuorophores are a fluorescent chemical compound that can re-emit light upon light excitation. Normally used to produce absorbance and emission spectra.

3 0
2 years ago
If the value of Kc for the reaction is 2.50, what are the equilibrium concentrations if the reaction mixture was initially 0.500
ratelena [41]

<u>Answer:</u> The equilibrium concentration of sulfur dioxide, nitrogen dioxide, sulfur trioxide, nitrogen monoxide is 0.196 M, 0.196 M, 0.309 M and 0.309 M respectively.

<u>Explanation:</u>

We are given:

Initial concentration of sulfur dioxide = 0.500 M

Initial concentration of nitrogen dioxide = 0.500 M

Initial concentration of sulfur trioxide = 0.00500 M

Initial concentration of nitrogen monoxide = 0.00500 M

The chemical reaction follows:

                         SO_2+NO_2\rightleftharpoons SO_3+NO

<u>Initial:</u>             0.500  0.500      0.005   0.005

<u>At eqllm:</u>      0.500-x  0.500-x   0.005+x  0.005+x

The expression of equilibrium constant for the above reaction follows:

K_c=\frac{[SO_3][NO]}{[SO_2][NO_2]}

We are given:

K_c=2.50

Putting values in above equation, we get:

2.50=\frac{(0.005+x)\times (0.005+x)}{(0.500-x)\times (0.500-x)}\\\\x=0.304,1.37

Neglecting the value of x = 1.37, because change cannot be greater than the initial concentration

So, equilibrium concentration of sulfur dioxide = (0.500-x)=(0.500-0.304)=0.196M

Equilibrium concentration of nitrogen dioxide = (0.500-x)=(0.500-0.304)=0.196M

Equilibrium concentration of sulfur trioxide = (0.00500+x)=(0.00500+0.304)=0.309M

Equilibrium concentration of nitrogen monoxide = (0.00500+x)=(0.00500+0.304)=0.309M

Hence, the equilibrium concentration of sulfur dioxide, nitrogen dioxide, sulfur trioxide, nitrogen monoxide is 0.196 M, 0.196 M, 0.309 M and 0.309 M respectively.

4 0
2 years ago
The atoms of a certain element each contain 19 protons and 1 valence electron. Which statement correctly identifies this element
Leya [2.2K]

Answer

its a potassium elements

Explanation:

K 2,8,8,1     period num 4

                  group 1A

or 1s1 ,2s2 2p6, 3s1

its a metal reacted  rapidly with water to form a colorless basic solution of potassium hydroxide (KOH) and hydrogen gas (H2). The reaction continues even when the solution becomes basic. The resulting solution is basic because of the dissolved hydroxide. The reaction is exothermic.

3 0
1 year ago
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