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3 years ago

Today, placebos are sometimes used as a(n) _____ in experiments. dependent variable independent variable control

Chemistry

1 answer:

Elza [17]3 years ago

7 0

Answer:

independent variable control

Explanation:

Placebos have no direct impact on the variable being studied. They are used to protect the validity of the test results. If both a effective drug and a placebo were used in a trial, the expectation is that those on the drug will improve, but those on a placebo will not exhibit any improvements beyond what is normal, or expected. If subjects from both trisl exhibited the same level of improvement, then there exists a third variable that must be considered. Fior example, the individuals on the placebo may think positvely if they thought they were getting the real drug. That effect should be the same for the group receiving the actual drug. Or perhaps environmental conditions changed that impacted both groups equally.

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.400 moles of CO2 gas are confined in a 5.00-liter container at 25 °C. Calculate the pressure exerted in atmospheres and mm Hg.

solong [7]

The pressure exerted by 0.400 moles of carbon dioxide in a 5.00 Liter container at 25 °C would be 1.9563 atm or 1486.788 mm Hg.

<h3>The ideal gas law</h3>

According to the ideal gas law, the product of the pressure and volume of a gas is a constant.

This can be mathematically expressed as:

pv = nRT

Where:

p = pressure of the gas

v = volume

n = number of moles

R = Rydberg constant (0.08206 L•atm•mol-1K)

T = temperature.

In this case:

p is what we are looking for.

v = 5.00 L

n = 0.400 moles

T = 25 + 273

= 298 K

Now, let's make p the subject of the formula of the equation.

p = nRT/v

= 0.400 x 0.08206 x 298/5

= 1.9563 atm

Recall that: 1 atm = 760 mm Hg

Thus:

1.9563 atm = 1.9563 x 760 mm Hg

= 1486.788 mm Hg

In other words, the pressure exerted by the gas in atm is 1.9563 atm and in mm HG is 1486.788 mm Hg.

More on the ideal gas law can be found here: brainly.com/question/28257995

#SPJ1

8 0

1 year ago

A reaction begins with 130.5g of substance X and substance Y. How many grams of

Paha777 [63]

Answer:

130.5g

Explanation:

At the of the reaction, the combined mass of X and Y will be 130.5g.

The premise for this conclusion is based on the law of conservation of matter.

This law states that "in a chemical reaction, matter is neither created nor destroyed but changed from one form to another".

In essence, in a chemical reaction, there is no mass loss.

The amount of product in the reaction is expected to be the same as the amount of reactants used in the experiment.
When we start with 130.5g then we should end with 130.5g

7 0

3 years ago

What is the mass of 6.12 moles of arsenic (As)?

Leokris [45]

Mole = Mass / Molar mass

6.12 moles = Mass / 74.92 g/mol

Mass = 6.12 moles x 74.92 g/mol

Mass = 458.51g

7 0

3 years ago

Read 2 more answers

The diagram below shows three stages in the water cycle. Condensation -----> 1----->2 Which statement is correct for the d

Allushta [10]

It is d I think best of luck

4 0

4 years ago

Read 2 more answers

Draw the products of benzoic acid reacting with sodium hydroxide.

Katena32 [7]

Answer:

Products: C6H5COO-Na+ (aq) + H2O (l)

Explanation:

when the benzoic acid react with sodium hydroxide, the acid part i.e carboxyl group is react with the base and produce ionic compound sodium benzoate (C6H5COO-Na+).

Chemical equation:

C6H5COOH + NaOH → C6H5COO-Na+ + H2O

Chemical reaction with physical states:

C6H5COOH (s) + NaOH (aq) → C6H5COO-Na+ (aq) + H2O (l)

Sodium benzoate is very polar ionic compound and soluble in water. If we add HCl into this solution sodium benzoate will be converted back into benzoic acid.

Properties of benzoic acid:

1. it is colorless solid.

2. it is crystalline in nature.

3. it is aromatic compound with the formula C7H6O2.

4. it is soluble into benzene, alcohol and ether.

5. its molar mass is 122.12 g/mol.

Properties of sodium benzoate:

1. Sodium benzoate is white odorless chemical compound.

2. It is aromatic compound and molecular formula is C7H5NaO2.

3. Its molecular weight is 144.11 g/mol.

4. it is sweet in taste and soluble in water.

5. it is used as preservative because of its antimicrobial properties.

Properties of Sodium hydroxide:

1. it is colorless solid and inorganic compound.

2. it is crystalline in nature.

3. its molar mass is 40 g/mol.

4. its molecular formula is NaOH.

5. its melting point is 318 °C.

6 0

3 years ago