What is the total number of oxygen atoms on the left-hand side of this chemical equation?

A 40.27 g sample of a substance is initially at 24.8 °c. after absorbing 2099 j of heat, the temperature of the substance is 148

Darina [25.2K]

Q = mCΔT
Q is heat in joules, m is mass, C is specific heat, and delta T is change in temp

2099 J = (40.27g)(C)(148.5 - 24.8) = .421 J / gram K

6 0

3 years ago

What are the limitations of bohr's model of atom

nataly862011 [7]

Answer:

The Bohr Model is very limited in terms of size. Poor spectral predictions are obtained when larger atoms are in question. It cannot predict the relative intensities of spectral lines. It does not explain the Zeeman Effect, when the spectral line is split into several components in the presence of a magnetic field.

Explanation:

7 0

3 years ago

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If you have a pitcher of lemonade and the recipe calls for 2 lemons and you decided to use 4, would this be considered diluted o

pantera1 [17]

Answer: This would be considered concentrated because if you're upping the recipe on your own accord, it would be way more sour, causing the lemonade to be more concentrated. It would be diluted if you added less than 2 lemons.

7 0

3 years ago

Gallium is produced by the electrolysis of a solution made by dissolving gallium oxide in concentrated NaOH ( aq ) . Calculate t

Sedbober [7]

Answer:

Approximately $6.30\times 10^{-3}\;\rm mol$ .

Explanation:

The gallium here is likely to be produced from a $\rm NaGaO_2\, (aq)$ solution using electrolysis. However, the problem did not provide a chemical equation for that process. How many electrons will it take to produce one mole of gallium?

Note the Roman Numeral " $\mathtt{(III)}$ " next to $\rm Ga$ . This numeral indicates that the oxidation state of the gallium in this solution is equal to $+3$ . In other words, each gallium atom is three electrons short from being neutral. It would take three electrons to reduce one of these atoms to its neutral, metallic state in the form of $\rm Ga\, (s)$ .

As a result, it would take three moles of electrons to deposit one mole of gallium atoms from this gallium $\mathtt{(III)}$ solution.

How many electrons are supplied? Start by finding the charge on all the electrons in the unit coulomb. Make sure all values are in their standard units.

$t = \rm 80.0\; min = 80.0\; min \times 60\;s \cdot min^{-1} = 4800\; s$ .

$Q = I \cdot t = \rm 0.380 \; A \times 4800 \; s = 1.824\times 10^3\; C$ .

Calculate the number of electrons in moles using the Faraday's constant. This constant gives the size of the charge (in coulombs) on each mole of electrons.

$\begin{aligned} n(\text{electrons}) &= \frac{Q}{F} \cr &= \rm \dfrac{1.824\times 10^3\; C}{96485.332\; C \cdot mol^{-1}}\cr &\approx \rm 1.89\times 10^{-2}\; mol \end{aligned}$ .

It takes three moles of electrons to deposit one mole of gallium atoms $\rm Ga\, (s)$ . As a result, $\rm 1.89\times 10^{-2}\; mol$ of electrons would deposit $\displaystyle \rm \frac{1}{3}\times 1.89\times 10^{-2}\; mol \approx 6.30\times 10^{-3}\; mol$ of gallium atoms $\rm Ga\, (s)$ .

8 0

3 years ago

how many moles of water are in 1.23 x 10^18 water molecules? I need the answer in scientific notation ?

Ann [662]

Answer:

Moles=2.04×10^(-6)

Explanation:

No. Of moles=no. Of particles/ Avogadro's no

(Where no. Of particles may be atoms molecules or compounds)

Moles=1.23×10^18/6.022×10^23

Moles=0.204×10^(-5)

Moles=2.04×10^(-6)

8 0

3 years ago