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2 years ago

Calculate the energy in joules and calories required to heat 25.0 g of water from 12.5C to 25.7C

1 answer:

8 0

The heat (Q) required to raise the temp of a substance is:Q=m∗Cp∗ΔT where m is the mass of the object (25.0g in this case), Cp is the specific heat capacity of the substance (for water Cp = 1.00cal/gC, or 4.18J/gC,
and Dt is the change in temp.
You'll have to solve this twice, once with the Cp in calories, and once with the Cp in joules.
1380.72 Joules

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. A bright violet line occurs at 435.8 nm in the emission spectrum of mercury vapor. What amount of energy, in joules, must be r

Tom [10]

Answer : The energy released by an electron in a mercury atom to produce a photon of this light must be, $4.56\times 10^{-19}J$

Explanation : Given,

Wavelength = $435.8nm=435.8\times 10^{-9}m$

conversion used : $1nm=10^{-9}m$

Formula used :

$E=h\times \nu$

As, $\nu=\frac{c}{\lambda}$

So, $E=h\times \frac{c}{\lambda}$

where,

$\nu$ = frequency

h = Planck's constant = $6.626\times 10^{-34}Js$

$\lambda$ = wavelength = $435.8\times 10^{-9}m$

c = speed of light = $3\times 10^8m/s$

Now put all the given values in the above formula, we get:

$E=(6.626\times 10^{-34}Js)\times \frac{(3\times 10^{8}m/s)}{(435.8\times 10^{-9}m)}$

$E=4.56\times 10^{-19}J$

Therefore, the energy released by an electron in a mercury atom to produce a photon of this light must be, $4.56\times 10^{-19}J$

3 0

3 years ago

A solution of HCl has a concentration of 1.20 x 10-2 M. What is the pH of this solution?

Westkost [7]

-log (1.2x10^-2) = 1.92 so C

3 0

2 years ago

Read 2 more answers

What are the n, l, and possible ml values for the 2p and 5f sublevels?

elixir [45]

Answer:

1. 2p sublevels, n = 2, orbital p, l = 1, ml = 0, ±1

2. 5f sublevels n = 5, orbital f, l = 3, ml = 0, ±1, ±2, ±3

Explanation:

The rules for electron quantum numbers are:

1. Shell number, 1 ≤ n

2. Subshell number, 0 ≤ l ≤ n − 1

3. Orbital energy shift, -l ≤ ml ≤ l

4. Spin, either -1/2 or +1/2

So,

1. 2p sublevels,

n = 2, orbital p, so l = 1, ml = 0, ±1

2. 5f sublevels

n = 5, orbital f, so l = 3, ml = 0, ±1, ±2, ±3

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2 years ago

The law of conservation of matter states that matter cannot be created or destroyed. This law applies when a chemical change occ

lora16 [44]

It says it will never change. So whatever it was before the change, it will be the same after the change. So, 200 should be correct.

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2 years ago

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Sergeu [11.5K]

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