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2 years ago

How many calories are needed to raise the temperature of 25 grams of water form 50°C to 70°C. The specific heat of water is

Chemistry

2 answers:

Papessa [141]2 years ago

7 0

Answer:

500 cal

Explanation:

Gala2k [10]2 years ago

4 0

Answer:

500 cal

Explanation:

m=25g,c=1cal/g, change in temperature=70-50,20 degree Celsius Q=?

using formula Q=mxcx change in theta

Q=25x1x20

Q=500cal

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1. A sample of gas has an initial volume of 25 L and an initial pressure of 123.5 kPa. If the pressure changes to

sveta [45]

Answer:

$\large \boxed{\text{17.mL}}$

Explanation:

The temperature and amount of gas are constant, so we can use Boyle’s Law.

$p_{1}V_{1} = p_{2}V_{2}$

Data:

$\begin{array}{rcrrcl}p_{1}& =& \text{123.5 kPa}\qquad & V_{1} &= & \text{25 L} \\p_{2}& =& \text{179.9 kPa}\qquad & V_{2} &= & ?\\\end{array}$

Calculations:

$\begin{array}{rcl}123.5 \times 25 & =& 179.9V_{2}\\3088 & = & 179.9V_{2}\\V_{2} & = &\dfrac{3088}{179.9}\\\\& = &\textbf{17 L}\\\end{array}\\\text{The new volume of the gas is } \large \boxed{\textbf{17 L}}$

6 0

2 years ago

The reaction 2PH3(g)+As2(g)⇌2AsH3(g)+P2(g) has Kp=2.9×10−5 at 873 K. At the same temperature, what is Kp for each of the followi

slavikrds [6]

Answer:

Part A

Kp = 3.4 x 10⁴

Part B

Kp = 2.4 x 10⁻¹⁴

Part C

Kp = 1.2 x 10⁹

Explanation:

2PH₃(g) + As₂(g) ⇌ 2 AsH₃(g) + P₂(g) Kp = 2.9 x 10⁻⁵

Kp = [AsH₃]²[P₂]/[PH₃]²[As] = 2.9 x 10⁻⁵

Part A

it is the inverse of the equilibrium given

Kp(A) = 1/ Kp = 1 / 2.9 x 10⁻⁵ = 3.4 x 10⁴

Part B

Is the equilibrium where the coefficients have been multiplied by 3,

Kp(B) = ( Kp )³ = ( 2.9 x 10⁻⁵ )³ = 2.4 x 10⁻¹⁴

Part C

This is the reverse equilibrium multipled by 2.

Kp(C) = ( 1/Kp)² = ( 1/ 2.9 x 10⁻⁵ )² = 1.2 x 10⁹

8 0

2 years ago

I need help with the question in the photo!!

Y_Kistochka [10]

Answer:

a semi-crystalline structure is formed, which holds the water molecules apart, making ice less dense than liquid water, such that it floats. This means that it insulates the water beneath, allowing organisms in the liquid water to survive. Cohesion is the tendency of molecules within a substance to ‘ stick together

explanation:

4 0

3 years ago

Read 2 more answers

Which bonds form in the reaction shown in the diagram?

lesya692 [45]

Explanation:

The bond between C and O in CO₂ and O and H in H₂O

Therefore,

Option C is correct✔

7 0

2 years ago

Read 2 more answers

What is the % dissociation of a solution of acetic acid if at equilibrium the solution has a pH = 4.74 and a pKa = 4.74?

Ymorist [56]

Answer:

$\% diss = 50\%$

Explanation:

Hello there!

In this case, when considering weak acids which have an associated percent dissociation, we first need to set up the ionization reaction and the equilibrium expression:

$HA\rightleftharpoons H^++A^-\\\\Ka=\frac{[H^+][A^-]}{[HA]}$