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erica [24]
3 years ago
12

Can you help me please?

Chemistry
1 answer:
almond37 [142]3 years ago
7 0

Explanation:

Physical changes only change the appearance of a substance, not its chemical composition.

Chemical changes cause a substance to change into an entirely substance with a new chemical formula.

Chemical changes are also known as chemical reactions. The “ingredients” of a reaction are called reactants, and the end results are called products

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Given similar concentrations, the stronger acid corresponds to the lower pH. Comment on the relative strengths of the acids H3PO
andreyandreev [35.5K]

Answer:

H3PO4 is stronger than H2PO4- because

H3PO4 dissociation constant is 6.9×10^-3

H2PO4^- dissociation constant is 6.2×10^-8

7 0
2 years ago
Phosphate buffers are commonly used in biological research. If a small amount of strong acid is added to a buffer solution that
lozanna [386]

Answer:

A) [H3PO4] will increase, [KH2PO4] will decrease, and pH will slightly decrease.

Explanation:

A buffer is a solution which resists changes to its pH when a small amount of acid or base is added to it.

Buffers consist of a weak acid (HA) and its conjugate base (A–) or a weak base and its conjugate acid. Weak acids and bases do not completely dissociate in water, and instead exist in solution as an equilibrium of dissociated and undissociated species. When a small quantity of a strong acid is added to a buffer solution, the conjugate base, A-, reacts with the hydrogen ions from the added acid to form the weak acid and a salt thereby removing the extra hydrogen ions from the solution and keeping the pH of the solution fairly constant. On the other hand, if a small quantity of a strong base is added to the buffer solution, the weak acid dissociates further to release hydrogen ions which then react with the hydroxide ions of the added base to form water and the conjugate base.

For example, if a small amount of strong acid is added to a buffer solution that is 0.700 M H3PO4 and 0.700 M KH2PO4, the following reaction is obtained:

KH₂PO₄ + H+ ----> K+ + H₃PO₄

Therefore, [H₃PO₄] will increase, [KH₂PO₄] will decrease, and pH will slightly decrease.:

4 0
3 years ago
A sample of gas has a volume of 100. L at 17 °C and 800. torr. To what temperature must the gas be cooled in order for its volum
Romashka [77]

Answer:

108.81 K

Explanation:

First convert 17 °C to Kelvin:

  • 17 + 273.16 = 290.16 K

Assuming ideal behaviour, we can solve this problem by using the<em> combined gas law</em>, which states that at constant composition:

  • P₁V₁T₂=P₂V₂T₁

Where in this case:

  • P₁ = 800 torr
  • V₁ = 100 L
  • T₂ = ?
  • P₂ = 600 torr
  • V₂ = 50 L
  • T₁ = 290.16 K

We <u>input the data</u>:

  • 800 torr * 100 L * T₂ = 600 torr * 50 L * 290.16 K

And <u>solve for T₂</u>:

  • T₂ = 108.81 K
6 0
3 years ago
Please help ASAP 100 points points help I will mark you as brainlister
Vlada [557]

this is lithium ion with a +1 charge

7 0
4 years ago
Read 2 more answers
2 A 3-meter-long ramp was used to lift gold into railroads for transfers. The railroads were 1 meter off the ground. What was th
Nataliya [291]

Answer:

3

Explanation:

For an ideal ramp, M.A/V.R = 1 where M.A = mechanical advantage and V.R = velocity ratio.

Now, V.R = distance moved by effort, d'/distance moved by load, d = d'/d

Now, d' = 3 m and d = 1 m.

So, V.R = d'/d = 3 m/1 m = 3

From M.A/V.R = 1

M.A = V.R = 3

So, the ideal mechanical advantage of the ramp M.A = 3  

6 0
3 years ago
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