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3 years ago

Which is sign that work is being done

Chemistry

2 answers:

madreJ [45]3 years ago

7 0

Answer:

If it is positive energy it enters the system.If it is negative it leaves the system.Therefore if work is done on the system it's a sign of positive & if work is done by the system its a sign or negative.

Explanation:

hope this helps!

Mrac [35]3 years ago

3 0

An$$$$$$$$$$$

Explanation:

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Im found a tool in his father’s toolbox and was curious about what it is used for. What does this tool do?

uranmaximum [27]

It measures the length

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4 years ago

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How many dm3 of hydrogen are released when 3 g of potassium is reacted with hydroiodic acid?

nlexa [21]

Answer:

V = 0.0859dm³

Explanation:

Hydroiodic acid, HI, reacts with potassium, K, to produce potassium iodide, KI, and hydrogen, as follows:

2HI + 2K → 2KI + H₂(g)

To solve this question we have to find the moles of hydrogen produced knowing that 2 moles of K produce 1 mole of H₂. With the moles of hydrogen we can find the volume of hydrogen assuming there are STP conditions:

Moles K -Molar mass: 39.0983g/mol-

3g * (1mol / 39.0983g) = 0.0767 moles of K

Moles H₂:

0.0767 moles of K * (1mol H₂ / 2mol K) = 0.03836 moles H₂

Using: PV = nRT; V = nRT / P

Where V is volume in dm³,

n are moles of gas: 0.03836 moles,

R is gas constant = 0.082atm*dm³/molK

T is absolute temperature = 273.15K at STP

and P is pressure = 1atm

The volume of the gas is:

V = 0.03836mol*0.082atm*dm³/molK*273.15K / 1atm

8 0

3 years ago

1. What does a chemical change always result in?

Naddika [18.5K]

Answer:

1)New substance

2)Exothermic reaction(reaction which releases heat or light to the environment)

3)donate

4)buffers

5)salt(base)

6)NAOH

7)neutralisation reaction

8)It decreases

9)It is neutral

8 0

3 years ago

A certain flexible weather balloon contains 3.5 L of helium gas. Initially, the balloon is in WP at 8500ft, where the temperatur

Advocard [28]

Answer:

$\large \boxed{\text{3.9 L}}$

Explanation:

We can use the Combined Gas Laws to solve this problem

$\dfrac{p_{1}V_{1} }{T_{1}} = \dfrac{p_{2}V_{2}}{T_{2}}$

Data

p₁ = 571.2 Torr; p₂ = 400 Torr

V₁ = 3.5 L; V₂ = ?

T₁ = 21.5 °C; T₂ = 6.8 °C

Calculations

(a) Convert the temperatures to kelvins

T₁ = (21.55 + 273.15) K = 294.70 K

T₂ = (6.8 + 273.15) K = 279.95 K

(b) Calculate the new volume

$\begin{array}{rcl}\dfrac{p_{1}V_{1} }{T_{1}} & = & \dfrac{p_{2}V_{2}}{T_{2}}\\\\\dfrac{\text{571.2 Torr $\times$ 3.5 L}}{\text{294.65 K}} & = & \dfrac{\text{400 Torr} \times V_{2}}{\text{279.95 K}}\\\\\text{6.78 L} & = & \text{1.429V}_{2}\\\\V_{2} & = & \textbf{4.7 L}\\\end{array}\\\text{The new volume of the balloon is $\large \boxed{\textbf{4.7 L}}$}$