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DiKsa [7]
3 years ago
12

Ivan wants to test how the amount of water consumed each day affects the number of facial blemishes people receive over a month.

He gathers 12 people and divides them into 3 groups. He keeps everything the same for each group except for daily water and food intake. Throughout the month, Ivan tallies the number of facial blemishes each individual receives. The table details how Ivan changed the independent variables for each group. Note: Group 1 is Ivan's control group. What error did Ivan make in the design of his inves
Chemistry
2 answers:
german3 years ago
7 0
He didn’t keep food intake the same which is important because diet can effect skin problem
Viktor [21]3 years ago
6 0
Some people naturally have more or less blemishes than others because of genes
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What are some ways that students and staff of a school can help slow water, land, and air pollution?
Nata [24]

Answer:

By recycling and cleaning up there community.

Explanation:

6 0
2 years ago
Read 2 more answers
Be sure to answer all parts. Calculate ΔH o for the following reaction in two ways, using the data given below. H2(g) + I2(g) →
Fantom [35]

Answer:

a) ΔH°rxn = -9.2kJ/mol

b) ΔH°rxn = -9.2kJ/mol

Explanation:

Using Hess's law, you can find ΔH of a reaction from ΔH of formation of the substances involved in the reaction, thus:

ΔH°rxn = ∑(BE(reactants)) − ∑(BE(products))

Or:

ΔH°rxn = ∑(nΔH°f (products)) − ∑(mΔH°f (reactants))

For the reaction:

H₂(g) + I₂(g) → 2HI(g)

a) Using the first equation:

ΔH°rxn = ΔH (H-H) + ΔH (I-I) - 2ΔHBE (H-I)

ΔH°rxn = 436.4kJ + 151kJ - 2×298.3kJ

<em>ΔH°rxn = -9.2kJ/mol</em>

<em />

b) Using the second equation:

ΔH°rxn = 2Δ°f (HI) − ΔH°f (H₂) - ΔH°f (I₂)

ΔH°rxn = 2×25.9kJ - 0kJ - 61.0kJ

<em>ΔH°rxn = -9.2kJ/mol</em>

<em />

7 0
3 years ago
Recycling of aluminum cans is an example of A) increasing entropy is a nonspontaneous process B) decreasing entropy is a nonspon
Helen [10]

Answer:

B) decreasing entropy is a non-spontaneous process

Explanation:

3 0
3 years ago
calculate how many milliliters of 0.142 M NaOH are needed to completely neutralize 21.4 mL of 0.294 M H2C4H4O6.
Flura [38]

Answer:

The answer to your question is 88.7 ml

Explanation:

Data

Volume = ?

Concentration of NaOH = 0.142 M

Volume of H₂C₄H₄O₆ = 21.4 ml

Concentration of H₂C₄H₄O₆ = 0.294 M

Balanced chemical reaction

               2 NaOH + H₂C₄H₄O₆  ⇒  Na₂C₄H₄O₆  +  2H₂O

1.- Calculate the moles of H₂C₄H₄O₆

Molarity = moles/volume

Solve for moles

moles = Molarity x volume

Substitution

moles = 0.294 x 21.4/1000

Result

moles = 0.0063

2.- Use proportions to calculate the moles of NaOH

              2 moles of NaOH ------------------ 1 moles of H₂C₄H₄O₆

               x                           ------------------ 0.0063 moles

               x = (0.0063 x 2) / 1

               x = 0.0126 moles of NaOH

3.- Calculate the volume  of NaOH

Molarity = moles / volume

Solve for volume

Volume = moles/Molarity

Substitution

Volume = 0.0126/0.142

Result

Volume = 0.088 L or 88.7 ml

3 0
3 years ago
You wish to make a 0.299 M hydroiodic acid solution from a stock solution of 6.00 M hydroiodic acid. How much concentrated acid
Art [367]

Answer:

V_1=2.49mL

Explanation:

Hello,

In this case, considering that the moles of hydrioiodic acid remain unchanged during the dilution process:

n_{HI}=n_{HI}

One could apply the following equality in terms of molarity:

V_1M_1=V_2M_2

Whereas the subscript 1 accounts for the solution before the dilution and 2 after the dilution, therefore, the required volume of 6.00 M acid is:

V_1=\frac{V_2M_2}{M_1} =\frac{50.0mL*0.299M}{6.00M}=2.49mL

Best regards.

5 0
3 years ago
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