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2 years ago

Formulate a sample scientific hypothesis

Chemistry

2 answers:

Ann [662]2 years ago

8 0

Answer:

Explanation:

A hypothesis can be define as a presumed statement or prediction that is required to be tested using a suitable scientific methodology. A hypothesis is required to be tested. It includes the facts or evidences which are required to be verified by the experimentation procedures.

Drinking sugary drinks daily leads to obesity. is the example of sample scientific hypothesis it can be tested using experimentation procedures.

Andrei [34K]2 years ago

3 0

<span>If the water faucet is opened, then the amount of water flowing will increase. </span>

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if an object has a mass of 60 grams in a volume of 120 cm3 then calculate the density would this object sink or float

Ivanshal [37]

Answer: 0.5 g/cm^3

Density equals mass divided by volume so..

60/120 is 0.5 g/cm^3

7 0

2 years ago

What is the molar mass of a gas which has a density of 0.00249 g/mL at 20.0 degrees celcius and 744.0 mm Hg?

creativ13 [48]

61.24 is the molar mass of a gas which has a density of 0.00249 g/mL at 20.0 degrees celcius and 744.0 mm Hg.

Explanation:

given that:

density = 0.00249 g/ml ( $\frac{mass}{volume}$ ) or 2.49 grams/litre

P = 744 mm Hg OR 0.978 atm

T = 20 Degrees or 293.15 Kelvin

R = 0.08206 Litre atm/mole K

molar mass =?

Formula used/

PV = nRT equation 1

here n is number of moles:

n = $\frac{mass}{atomic mass}$

putting the value of n and value of density in the equation 1:

PV = $\frac{mass}{molar mass}$ x RT

molar mass = $\frac{mass}{volume}$ x $\frac{RT}{P}$

= density x $\frac{RT}{P}$

= $\frac{2.49 x 0.08276 x 293.15}{0.978}$

= 61.24 is the molar mass of the gas.

8 0

2 years ago

The average lung capacity of a human is 6.0L.

Darya [45]

Answer:

(a) 0.25 mol

(b) 0.11 mol

Explanation:

(a)

We use the equation given by ideal gas which follows:

$PV=nRT$

where,

P = pressure of the gas = 1.00 atm

V = Volume of the gas = 6.0 L

T = Temperature of the gas = 298 K

R = Gas constant = $0.0821\text{ L.atm }mol^{-1}K^{-1}$

n = number of moles = ?

Putting values in above equation, we get:

$1.00 atm\times 6.0L=n\times 0.0821\text{ L.atm }mol^{-1}K^{-1}\times 298K\\\\n=\frac{1.00\times 6.0}{0.0821\times 298}=0.25mol$

(b)

We use the equation given by ideal gas which follows:

$PV=nRT$

where,

P = pressure of the gas = 0.296 atm

V = Volume of the gas = 6.0 L

T = Temperature of the gas = 200 K

R = Gas constant = $0.0821\text{ L.atm }mol^{-1}K^{-1}$

n = number of moles = ?

Putting values in above equation, we get:

$0.296 atm\times 6.0L=n\times 0.0821\text{ L.atm }mol^{-1}K^{-1}\times 200K\\\\n=\frac{0.296\times 6.0}{0.0821\times 200}=0.11mol$

(c)

We use the equation given by ideal gas which follows:

$PV=nRT$

where,

P = pressure of the gas = 30 atm

V = Volume of the gas = 6.0 L

T = Temperature of the gas = 250 K

R = Gas constant = $0.0821\text{ L.atm }mol^{-1}K^{-1}$

n = number of moles = ?

Putting values in above equation, we get:

$30 atm\times 6.0L=n\times 0.0821\text{ L.atm }mol^{-1}K^{-1}\times 250K\\\\n=\frac{30\times 6.0}{0.0821\times 250}=8.77mol$

8 0

3 years ago

Consider a galvanic cell in which Al 3 + Al3+ is reduced to elemental aluminum and magnesium metal is oxidized to Mg 2 + Mg2+ .

olga nikolaevna [1]

Answer:

Anode:

3Mg(s) ----------> 3Mg2+(aq) + 6e

Cathode:

2Al3+(aq) +6e ---------> 2Al(s)

Explanation:

Anode:

3Mg(s) ----------> 3Mg2+(aq) + 6e

Cathode:

2Al3+(aq) +6e ---------> 2Al(s)

Magnesium is more electro positive than aluminum hence it functions as the anode. Six electrons are lost/gained in the redox process as shown in the oxidation and reduction half reaction equations above. Magnesium is oxidized to magnesium ion while aluminum is reduced to elemental aluminum.

5 0

3 years ago

Read 2 more answers

3. Which change of state involves adding thermal energy to a substance!

MakcuM [25]

Answer:

A) Melting

Explanation:

The three changes of phase described in this problem are:

Melting: melting occurs when a substance in solid state turns into liquid state. Since molecules in liquid state have more energy than molecules in solid state (because in liquids, molecules can slide past each other, while in solids they can't move, but only vibrate), thermal energy must be added in order to melt a substance

Freezing: freezing occurs when a liquid substance turns into solid state (the opposite of melting). Since molecules in liquid state have more energy than molecules in solid state, thermal energy must be removed from the substance in order to cause freezing
Condensation: condensation occurs when a gaseous substance turns into liquid state. Since molecules in gaseous state have more energy than molecules in liquid state, thermal energy must be removed from the substance in order to cause condensation

So the correct option is

A) melting

5 0

3 years ago