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1 year ago

Scientific method practice hypothesis construction & experimental design

1 answer:

3 0

A supposition or proposed explanation made on the basis of limited evidence as a starting point for further investigation

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If my primary DNA strand is ATACCGCAA a write the complimentary DNA strand

Liula [17]

Answer:

TATGGCGTT

Explanation:

Complimentary base pairs:

A-T

C-G

Use the other letter for complimentary strands

6 0

3 years ago

Read 2 more answers

The complete combustion of propane (C3H8) in the presence of oxygen yields CO2 and H2O: C3H8 (g) + 5O2 (g) 3CO2 (g) + 4H2O (g) a

mixas84 [53]

Answer:

26.9 L is the volume of CO₂, we obtained

Explanation:

The reaction is: C₃H₈(g) + 5O₂(g) → 3CO₂ (g) + 4H₂O (g)

Let's determine the reactants moles:

27.5 g . 1mol / 44 g = 0.625 moles

We need density of O₂ to determine mass and then, the moles.

O₂ density = O₂ mass / O₂ volume

O₂ density . O₂ volume = O₂ mass

1.429 g/L . 45L = O₂ mass → 64.3 g

Moles of O₂ → 64.3 g . 1mol/32g = 2.009 moles

Let's find out the limiting reactant:

1 mol of propane needs 5 moles of oxygen to react

Then, 0.625 moles will react with (0.625 . 5)/1 = 3.125 moles of O₂

Oxygen is the limiting reactant, we need 3.125 moles but we only have 2.009 moles

Ratio is 5:3. 5 moles of O₂ produce 3 moles of CO₂

Therefore, 2.009 moles of O₂ must produce (2.009 .3) /5 = 1.21 moles of CO₂. Let's find out the volume, by Ideal Gases Law (STP are 1 atm and 273K, the standard conditions)

1 atm . V = 1.21 moles . 0.082 . 273K

V = (1.21 moles . 0.082 . 273K) / 1atm = 26.9 L

3 0

3 years ago

What is the significance of "Er" in the diagram?

Drupady [299]

Answer:

The significance of "Er" in the diagram is :

B.) Threshold energy for reaction

Explanation:

Threshold energy : It is total amount of energy required by the reactant molecule to reach the transition state .

Activation energy : It is the excess energy absorbed by the molecules to reach the transition state.

Activation Energy = Threshold Energy - Average Kinetic Energy

This means Activation energy decreases on increasing kinetic energy

On increasing Temperature average kinetic energy of the molecule increases which reduces the activation energy and the reaction occur faster in that case.

Catalyst also reduces the Activation energy.

Er = Threshshold energy for reaction at 30 degree

Ea = Activation Energy

The given figure shows that the threshold energy decreases on increasing the temperature

Only the molecule having energy greater than Er can react to form product