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3 years ago

PLEASE HELP ME!!! I WILL GIVE BRAINLIEST TO WHOEVER ANSWERS CORRECTLY FIRST!!! 20 points!!!

Chemistry

2 answers:

loris [4]3 years ago

8 0

The atomic number for Uranium is 92
The mass of Krypton is 92
There are 85 Barium neutrons
I think this reaction emits 3 neutrons? I'm not familiar with seeing neutrons being emitted in an equation, so don't take my word for that last one.

stepan [7]3 years ago

4 0

The atomic mass for Krypton is . (92,56,128,36)

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How much heat is required to change 100 g of ice (H2O) at 253 K to vapor (steam) at 393 K?

soldier1979 [14.2K]

Answer: The heat required will be 58.604 kJ.

Explanation:

To calculate the amount of heat required, we use the formula:

$Q= m\times c\times \Delta T$

Q= heat gained or absorbed = ? J

m = mass of the substance = 100 g

c = heat capacity of water = 4.186 J/g ° C

Putting values in above equation, we get:

$\Delta T={\text{Change in temperature}}=(393-253)K=140K=140^oC$

$Q=100g\times 4.186J/g^oC\times 140^oC$

Q = 58604 Joules = 58.604 kJ (Conversion factor: 1 kJ = 1000J)

Thus, heat released by 100 grams of ice is 58.604kJ.

3 0

4 years ago

Which of the following lists describes characteristics of a base? (3 points)

mel-nik [20]

Answer:

slippery, high pH, and caustic (last option)

Explanation:

when we say base we should think soap. soap is slippery. Bases give OH- ion. when OH- is combined with H+ ion it will create water which raises the pH. Since base can dissolve fats, ex: using dish liquid to cut grease on pots and pans etc.. they are caustic. Biologically they can disrupt the cell memebrane making it caustic to cell tissue.

3 0

3 years ago

Calculate the molarity of a solution containing 5.6 mol of sodium hydroxide dissolved in 2.1 L of water

yKpoI14uk [10]

2.0 MOL is the correct answer I believe

5 0

3 years ago

Calculate the ph at the equivalence point for the titration of 0.230 m methylamine (ch3nh2) with 0.230 m hcl. the kb of methylam

Vlad1618 [11]

Answer: The pH at the equivalence point for the titration will be 0.65.

Solution:

Let the concentration of $[OH^-]$ be x

Initial concentration of $[CH3NH_2]$ , c = 0.230 M

$CH_3NH_2+H_2O\rightleftharpoons CH_3NH_3^++OH^-$

at eq'm c-x x x

Expression of $K_b$ :

$K_b=\frac{[CH_3NH_3^+][+OH^-]}{[CH_3NH_2]}=\frac{x\times x}{c-x}=\frac{x^2}{c-x}$

Since ,methyl-amine is a weak base,c>>x so $c-x\approx c$ .

$K_b=\frac{x^2}{c}=5.0\times 10^{-4}=\frac{x^2}{0.230 M}$

Solving for x, we get:

$x=1.07\times 10^{-2} M$

Given, HCl with 0.230 M , it dissociates fully in water which means $[H^+]$ = 0.230 M

$[OH^-]=[H^+]$ will result in neutral solution, since $[OH^-]$

Remaining $[H^+]$ after neutralizing $[OH^-]$ ions

$[H^+]_{\text{left in solution}}=[H^+]-[OH^-]=0.230-1.07\times 10^{-2}=0.2193 M$

$pH=-log{[H^+]_{\text{left in solution}}=-log(0.2193)=0.65$

The pH at the equivalence point for the titration will be 0.65.

8 0

3 years ago

Which type of drugs kill pain by blocking impulses at specific receptor sites of the brain and spinal cord? narcotic analgesics

4vir4ik [10]

I believe the correct answer from the choices listed above is the second option. Analgesics are the drugs that kill pain by blocking impulses at specific receptor sites of the brain and spinal cord. Analgesics are drugs that alleviate pain without causing anesthesia. Hope this helps.

7 0

3 years ago