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3 years ago

Marcel conducts an experiment to test which stain remover works best on mustard stains. He wants to make sure that he

Chemistry

2 answers:

Anni [7]3 years ago

7 0

Answer: Repeat the experiment several times with the same variable and constants.

Explanation:

The experimental procedure should be performed many times so as to determine the effect of the stain remover on mustard stain in different conditions and while using different variables such as water and type of machine used. This will tell how useful the stain remover in all conditions provided to check the accuracy of the stain remover.

Vladimir [108]3 years ago

6 0

Answer: D. repeat the experiment several times with the same variable and constants

Explanation: Took the test

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True or false: Fungi are able to carry out photosynthesis, similar to plants

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Answer:

false

Explanation:

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2 years ago

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What color would litmus paper turn in a solution of baking soda? Explain your answer in terms of pH.

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2 years ago

Calculate δ h for the reaction:no (g) + o2 (g) ↔ no2 (g). given: 2o3(g) ↔ 3o2(g) δh=-426 kj o2(g) ↔ 2o(g) δh=+ 490 kj no(g) + o3

maks197457 [2]

To calculate the δ h, we must balance first the reaction:

NO + 0.5O2 -----> NO2

Then we write all the reactions,

2O3 -----> 3O2 δ h = -426 kj eq. (1)

O2 -----> 2O δ h = 490 kj eq. (2)

NO + O3 -----> NO2 + O2 δ h = -200 kj eq. (3)

We divide eq. (1) by 2, we get

O3 -----> 1.5O2 δ h = -213 kj eq. (4)

Then, we subtract eq. (3) by eq. (4)

NO + O3 -----> NO2 + O2 δ h = -200 kj
- (O3 -----> 1.5 O2 δ h = -213 kj)
NO -----> NO2 - 0.5O2 δ h = 13 kj eq. (5)

eq. (2) divided by -2. (Note: Dividing or multiplying by negative number reverses the reaction)

O -----> 0.5O2 δ h = -245 kj eq. (6)

Add eq. (6) to eq. (5), we get

NO -----> NO2 - 0.5O2 δ h = 13 kj
+ O -----> 0.5O2 δ h = -245 kj
NO + O ----> NO2 δ h = -232 kj

ANSWER: NO + O ----> NO2 δ h = -232 kj

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3 years ago

What is the result of multiplying (2.5 × 1010) × (2.0 × 10-7)?

Travka [436]

That would be A.

2.5*2*10^(10-7)=5*10^3

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3 years ago

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A student wants to make a 0.600 M aqueous solution of barium sulfate, BaSO4, and has a bottle containing 12.00 g of barium sulfa

love history [14]

Answer: The volume of the solution is 85.7 mL

Explanation:

Molarity is defined as the amount of solute expressed in the number of moles present per liter of solution. The units of molarity are mol/L. The formula used to calculate molarity:

$\text{Molarity of solution}=\frac{\text{Given mass of solute}\times 1000}{\text{Molar mass of solute}\times \text{Volume of solution (mL)}}$ .....(1)

We are given:

Molarity of solution = 0.600 M

Given mass of $BaSO_4$ = 12.00 g

We know, molar mass of $BaSO_4=[(1\times 137.33)+(1\times 32.07)+(4\times 16)]=233.4g/mol$

Putting values in equation 1, we get:

$0.600=\frac{12.00\times 1000}{233.4\times \text{Volume of solution}}\\\\\text{Volume of solution}=\frac{12.00\times 1000}{233.4\times 0.600}=85.68mL=85.7mL$

The rule of significant number that is applied for the problems having multiplication and division:

The least number of significant figures in any number of the problem determines the number of significant figures in the answer.

Here, the least number of significant figures is 3 that is determined by the number, 0.600. Thus, the answer must have these many significant figures only.

Hence, the volume of the solution is 85.7 mL

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2 years ago