State Hess' law of constant heat summation.

This means that the steel bar lost 14900 J of thermal energy. What is the change in temperature of the steel bar? Recall that th

stiv31 [10]

Answer:

ΔT=-747,13°C

Explanation:

Sensible heat is the amount of thermal energy that is required to change the temperature of an object, the equation for calculating the heat change is given by:

Q=msΔT

where:

Q, heat that has been absorbed or realeased by the substance [J]
m, mass of the substance [g]
s, specific heat capacity [J/g°C] (
ΔT, changes in the substance temperature [°C]

To solve the problem, we clear ΔT of the equation and then replace our data:

Q=msΔT

ΔT=Q/ms

Δ $T=\frac{-14900 J}{40,7g*0,49\frac{J}{gC} }=-747,13$ °C

(Note that Q=-14900 J because there is a LOST of thermal energy)

Thus, the change in temperature of the steel bar is -747,13°C, meaning that the temperature of the bar decreases.

5 0

2 years ago

Read 2 more answers

a.) The diameter of a uranium atom is 3.50 Å . Express the radius of a uranium atom in both meters and nanometers. b.) How many

Svetradugi [14.3K]

Answer:

Th answer to your question is:

a) 3.5 x10⁻¹⁰ meters; 0.35 nm

b) 6857142.86 atoms

c) Volume = 2.06 x 10⁻²³ cm³

Explanation:

a) data

Uranium atoms = 3.5A°

meters

1 A° ---------------- 1 x 10 ⁻¹⁰ m

3.5A° --------------- x

x = 3.5(1 x10⁻¹⁰)/ 1 = 3.5 x10⁻¹⁰ meters

1 A° ------------------ 0.1 nm

3.5 A° ---------------- 0.35 nm

b) 2.4 mm

Divide 2,40 mm / uranium diameter

But, first convert 3,5A° to mm = 3.5 x 10⁻⁷ mm

# of uranium atoms = 2.4 / 3.5 x 10⁻⁷ = 6857142.86

c) volume in cubic cm

Convert 3.5A° to cm = 3.5 x 10⁻⁸

Volume = 4/3 πr³ = (4/3) (3.14)(1.7 x10⁻⁸)³

Volume = 2.06 x 10⁻²³ cm³

6 0

2 years ago

Compare and contrast the functions of each of the following types of flasks: filter, Erlenmeyer, volumetric.

harkovskaia [24]

The Erlenmeyer Flask was introduced in 1861 by German chemist Emil Erlenmeyer and is shaped like a cone. This has a triangular shape and mouth wide for it to be easier to pour and store liquids. The Volumetric flask is used for preparing liquids with volumes of high precision. It has a pear-shaped body and a long neck with a circumferential fill line. The Filter Flask is also known as the A Büchner flask. It is like the Erlenmeyer but this one is thick-walled and has a special arm in the side. It is used for filtering liquid.

4 0

2 years ago

Rank the following from highest to lowest priority according to the Cahn-Ingold-Prelog system: -CH2CH3, -CHCH2, -CCH, -CH3.

mario62 [17]

Answer:

The order will be:

CCH > CHCH₂ > CH₂CH₃> CH₃

Explanation:

According to Cahn-Ingold-Prelog system we rank the groups based on the atomic number of directly attached atom with the chiral carbon.

For example: between C and H, we rank Carbon first.

If the same atoms are attached for different groups then we prioritized based on the second element with highest atomic number.

For example:

Among CH₃ and C₂H₅, the priority will be given to C₂H₅.

If an atom is double or triple bonded to the directly attached atom then each pi bond is considered to be a new atom.

Hence CH=CH₂ means, that there are two carbons attached to CH carbon.

So the order based on above selection rules will be:

CCH > CHCH₂ > CH₂CH₃> CH₃

7 0

2 years ago

In chemistry we did a lab examining iron nails corroding in agar. One of the nails was wrapped in zinc, and the nail did not rus

forsale [732]

Answer:

Zn(OH)₂

Explanation:

Zn is above Fe in the activity series, so it is more readily oxidized:

Zn(s) ⟶ Zn²⁺(aq) + 2e⁻

The zinc ions go into solution.

The electrons travel from the Zn to the surface of the iron nail, where they reduce the water to hydrogen and hydroxide ions.

2H₂O(ℓ) + 2e⁻ ⟶ H₂(g) + 2OH⁻(aq)

Neither the zinc ions nor the hydroxide ions can move far through the gel.

Their concentration builds up around the hail. The ions find each other and form a precipitate.

Zn²⁺(aq) + 2OH⁻(aq) ⟶ Zn(OH)₂(s)

4 0

2 years ago