Which of the following is an acid? (3 points) Be(OH)2 HCI LiBr NH3

When a 0.245-g sample of benzoic acid is combusted in a bomb calorimeter, the temperature rises 1.643 ∘C . When a 0.260-g sample

sveticcg [70]

Answer:

The heat of combustion per moles of caffeine is 4220 kJ/mol

Explanation:

Step 1: Data given

⇒ When benzoic acid sample of 0.245 grams is burned the temperature rise is 1.643 °C

⇒ When 0.260 gram of caffeine is burned, the temperature rise is 1.436 °C

⇒ Heat of combustion of benzoic acid = 26.38 kJ/g

Step 2: Calculate the heat released: for combustion of benzoic acid

0.245 g benzoic acid * 26.38 kJ/g = 6.4631 kJ

Step 3: Calculate the heat capacity of the calorimeter:

c = Q/ΔT

Q = 6.4631 kJ / 1.643°C = 3.934 kJ/ °C

Step 4: Calculate moles of a 0.260 g sample of caffeine:

Moles caffeine = Mass caffeine / Molar mass caffeine

0.260 grams/ 194.19 g/mol = 0.0013389 moles

Step 5: Calculate heat released: for combustion of caffeine

Q = c * ΔT

Q = 3.934 kJ/°C * 1.436 °C = 5.65 kJ

Step 6: Calculate the heat of combustion per mole of caffeine

5.65 kJ / 0.0013389 moles = 4219.9 kJ/mol ≈ 4220 kJ/mol

The heat of combustion per moles of caffeine is 4220 kJ/mol

4 0

3 years ago

I need to find the orbit notation 1. Ne - 1s 2s 2p 3s 3p 4s 3d 4p 5s

weeeeeb [17]

Answer:

1s*2 2s*2 2p*6

Explanation:

atomic number of neon is 10 so the s-shell contains 2 electron and p-shell contains 6

3 0

3 years ago

How much faster does ethane (C2H6) gas travel compared to chlorine gas?

zimovet [89]

Answer:

$\large \boxed{\text{54 $\, \%$ faster }}$

Explanation:

$v_{\text{rms}} \propto \sqrt{\dfrac{3RT}{M}$

if temperature is constant.

$v_{\text{rms}} \propto \sqrt{\dfrac{1}{M}$

if we are comparing two gases,

$\dfrac{v_{2}}{v_{1}} = \sqrt{\dfrac{M_{1}}{M_{2}}}$

Let chlorine be Gas 1 and ethane be Gas 2

Data:

M₁ = 70.91 g/mol

M₂ = 30.07 g/mol

Calculation

$\begin{array}{rcl}\dfrac{v_{2}}{v_{1}} & = & \sqrt{\dfrac{M_{1}}{M_{2}}}\\\\& = & \sqrt{\dfrac{70.91}{30.07}}\\\\& = & \sqrt{2.358}\\\\& = & \mathbf{1.54}\\\end{array}\\\text{Ethane molecules travel at 1.54 times the speed of chlorine molecules}\\\text{or $\large \boxed{\textbf{54 $\%$ faster }}$ than chlorine molecules}$