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aleksklad [387]
3 years ago
15

A teacher cut an apple into three wedges of the same size.She dipped one wedge in lemon juice, dipped another in water ,and left

one alone. Then she left the wedges on a paper towel on her desk. After 1 hour, only the wedge that had been dipped in lemon juice was still yellow. The other two wedges had turned brown.
Chemistry
1 answer:
jasenka [17]3 years ago
7 0
It’s national park and I have to do the same as I have to get some money drops and then we will have a lot to go back on and I get the same
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____________________ energy is the energy of movement.
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Thermal energy is the energy of movement.

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Answer: Combustion changes the potential chemical energy into kinetic energy in the form of heat. For combustion an organic wood combines with oxygen already in the air and undergoes a chemical reaction that gives off carbon dioxide,water,and energy in the form of heat and light.
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3 years ago
Compare and contrast how observations and results can be used to
worty [1.4K]

Answer:

by statistical analyses, especially by determining the p-value

Explanation:

In general, observations and results obtained from experimental procedures are subjected to a statistical test to check the robustness of the working hypothesis. The p-value is the most widely used statistical index in order to test such observations and results. The p-value is the statistical probability of obtaining extreme observed results when the null hypothesis is considered correct. A p-value lesser than 0.05 generally is considered statistically significant and then the null hypothesis can be rejected. In consequence, a very low p-value (which is obtained by statistical analysis of the observations and results), indicates that there is strong evidence in support of the alternative hypothesis.

5 0
3 years ago
Read 2 more answers
The Ka for formic acid (HCO2H) is 1.8 × 10-4. What is the pH of a 0.35 M aqueous solution of sodium formate (NaHCO2)?
anzhelika [568]

Answer:

9.36

Explanation:

Sodium formate is the conjugate base of formic acid.

Also,

K_a\times K_b=K_w

K_b for sodium formate is K_b=\frac {K_w}{K_a}

Given that:

K_a of formic acid = 1.8\times 10^{-4}

And, K_w=10^{-14}

So,

K_b=\frac {10^{-14}}{1.8\times 10^{-4}}

K_b=5.5556\times 10^{-11}

Concentration = 0.35 M

HCOONa    ⇒     Na⁺ +    HCOO⁻

Consider the ICE take for the formate  ion as:

                                   HCOO⁻ + H₂O   ⇄   HCOOH + OH⁻

At t=0                              0.35                            -              -

At t =equilibrium           (0.35-x)                          x           x            

The expression for dissociation constant of sodium formate is:

K_{b}=\frac {[OH^-][HCOOH]}{[HCOO^-]}

5.5556\times 10^{-11}=\frac {x^2}{0.35-x}

Solving for x, we get:

x = 0.44×10⁻⁵  M

pOH = -log[OH⁻] = -log(0.44×10⁻⁵) = 4.64

pH + pOH = 14

So,

<u>pH = 14 - 4.64 = 9.36</u>

5 0
3 years ago
What does reaction b tell you about the type of molecule h2co3 is?
irinina [24]
H2o means water and co3 is co-signs
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