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3 years ago

SCIENCEEEE!!!! I NEED HELPPP

Chemistry

2 answers:

seraphim [82]3 years ago

4 0

Both are physical changes.

Hope this helps!! (:

valina [46]3 years ago

3 0

These are both physical changes can I get a brain list please

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A 25.0-mL sample of 0.150 M hydrocyanic acid is titrated with a 0.150 M NaOH solution. The Ka of hydrocyanic acid is 4.9 × 10-10

lara [203]

Answer:

The pOH = 1.83

Explanation:

Step 1: Data given

volume of the sample = 25.0 mL

Molarity of hydrocyanic acid = 0.150 M

Molarity of NaOH = 0.150 M

Ka of hydrocyanic acid = 4.9 * 10^-10

Step 2: The balanced equation

HCN + NaOH → NaCN + H2O

Step 3: Calculate the number of moles hydrocyanic acid (HCN)

Moles HCN = molarity * volume

Moles HCN = 0.150 M * 0.0250 L

Moles HCN = 0.00375 moles

Step 3: Calculate moles NaOH

Moles NaOH = 0.150 M * 0.0305 L

Moles NaOH = 0.004575 moles

Step 4: Calculate the limiting reactant

0.00375 moles HCN will react with 0.004575 moles NaOH

HCN is the limiting reactant. It will completely be reacted. There will react 0.00375 moles NaOH. There will remain 0.004575 - 0.00375 = 0.000825 moles NaOH

Step 5: Calculate molarity of NaOH

Molarity NaOH = moles NaOH / volume

Molarity NaOH = 0.000825 moles / 0.0555 L

Molarity NaOH = 0.0149 M

Step 6: Calculate pOH

pOH = -log [OH-]

pOH = -log (0.0149)

pOH = 1.83

The pOH = 1.83

6 0

3 years ago

I need help pleasee

Readme [11.4K]

Answer:

Explanation:

6. Where on the graph does adding heat energy NOT raise the temperature?

What is the heat energy DOING if it's not raising the temperature? :its being compressed I believe its vaporizing

7. What is temperature A called? Freezing

8. What is temperature B called? Vaporizing

4 0

3 years ago

What types of questions can be answered through science and what questions are beyond the boundaries of science? Be specific and

Anna [14]

The questions tha science can answer are those can be tested to try to find a definite answer.

For example, whether light is wave or particle is matter of science.

Questions that cannot have a definite answer are the field of religion or philosophy, and are out of the boundaries of science.

For example, does a criminal deserve the punishment of not seeing light? It is a moral question, which to be responded needs the intervention of philosophy and that could have different anwers at different times and in different societies.

3 0

3 years ago

Please Help!! How does alpha decay change the nucleus of radioactive atom.

cluponka [151]

Answer:

When atom undergoes the alpha emission the original atom convert into the atom having mass number less than 4 and atomic number 2 less than the starting atom.

Explanation:

Alpha radiations are emitted as a result of radioactive decay. The atom emit the alpha particles consist of two proton and two neutrons. Which is also called helium nuclei. When atom undergoes the alpha emission the original atom convert into the atom having mass number less than 4 and atomic number 2 less than the starting atom.

Properties of alpha radiation:

Alpha radiations can travel in a short distance.

These radiations can not penetrate into the skin or clothes.

These radiations can be harmful for the human if these are inhaled.

These radiations can be stopped by a piece of paper.

₉₂U²³⁸ → ₉₀Th²³⁴ + ₂He⁴ + energy

5 0

4 years ago

when a number in scientific notation contains a significant zero, is that zero also significant in the expanded notation? give t

AlexFokin [52]

I believe you are referring zero as the exponent. Any number (except 0) with exponent 0 is defined to mean 1.

For one thing, there is a rule:

a^m/ a^m = a^m-m = a^0

But (when a is not equal to 0),

a^m/ a^m = 1

Therefore, we must define a^0 as 1.

4 0

4 years ago