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2 years ago

Please help is for today

Chemistry

1 answer:

love history [14]2 years ago

5 0

Answer:

Our bodies are designed to regulate our temperature. When it's cold outside, your body makes sure to keep the blood flowing to your core and vital organs to keep them warm. This can change the amount of blood flow to your hands and feet, making them feel cold

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30PTS EASY QUESTION

irga5000 [103]

Thermal, electrical, chemical, nuclear, and electromagnetic energy. (just gave you more than two just incase)

4 0

2 years ago

Read 2 more answers

When 21.45 g of KNO3 was dissolved in water in a calorimeter, the temperature fell from 25.00°C to 14.14 °C. If the heat capacit

pashok25 [27]

25.9 kJ/mol. (3 sig. fig. as in the heat capacity.)

<h3>Explanation</h3>

The process:

$\text{KNO}_3\;(s) \to \text{KNO}_3\;(aq)$ .

How many moles of this process?

Relative atomic mass from a modern periodic table:

K: 39.098;
N: 14.007;
O: 15.999.

Molar mass of $\text{KNO}_3$ :

$M(\text{KNO}_3) = 39.098 + 14.007 + 3\times 15.999 = 101.102\;\text{g}\cdot\text{mol}^{-1}$ .

Number of moles of the process = Number of moles of $\text{KNO}_3$ dissolved:

$\displaystyle n = \frac{m}{M} = \frac{21.45}{101.102} = 0.212162\;\text{mol}$ .

What's the enthalpy change of this process?

$Q = C\cdot \Delta T = 0.505 \times (25.00 - 14.14) = 5.4843\;\text{kJ}$ for $0.212162\;\text{mol}$ . By convention, the enthalpy change $\Delta H$ measures the energy change for each mole of a process.

$\displaystyle \Delta H = \frac{Q}{n} = \frac{5.4843\text{kJ}}{0.212162\;\text{mol}} = 25.8\;\text{kJ}\cdot\text{mol}^{-1}$ .

The heat capacity is the least accurate number in these calculation. It comes with three significant figures. As a result, round the final result to three significant figures. However, make sure you keep at least one additional figure to minimize the risk of rounding errors during the calculation.

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2 years ago

KBr + AgNO3 → AgBr + KNO3<br><br><br> Which two chemicals are products in the chemical reaction?

iragen [17]

Answer:

Products are AgBr and KNO3

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2 years ago

Among the following options, a valid Lewis structure of __________ cannot be drawn without violating the octet rule.

Murrr4er [49]

Answer:

d. IF3

Explanation:

The Octet rule posits that atoms gain, atom lose, or share electrons in order to have a full valence shell of 8 electrons. This statement occurs when atoms also combine to form molecules until they attain or share eight valence electrons either by losing or gaining eletrons.

From the given options, a valid Lewis structure that cannot be drawn without violating the octet rule is IF3

8 0

2 years ago

An atom (not a hydrogen atom) absorbs a photon whose associated wavelength is 300 nm and then immediately emits photon whose ass

KIM [24]

Answer:

The net energy is 2.196 eV

Explanation:

Basically, the energy of an atom increases when it absorbs a photon. In addition, the wavelength of the emitted photon is longer such that the atom absorbed a net energy in the process.

Using:

ΔE = h*c*(1/λ $_{1}$ - 1/λ $_{2}$ )