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-BARSIC- [3]
3 years ago
7

If the temperature of 15 grams of water changes from 21C to 24C, how many joules of heat were involved? Show work

Chemistry
1 answer:
goblinko [34]3 years ago
6 0

Answer:

189 Joules

Explanation:

Applying,

Q = cm(t₂-t₁)............. equation 1

Where Q = Heat, c = specific heat capacity of water, m = mass of water, t₁ = Initial Temperature, t₂ = Final temperature.

From the question,

Given: m = 15 grams = 0.015 kg, t₁ = 21 °C, t₂ = 24 °C

Constant: c = 4200J/kg.°C

Substitute these values into equation 1

Q = 0.015×4200×(24-21)

Q = 0.015×4200×3

Q = 189 Joules

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The iupac name this compound​
MrRa [10]

Answer:

It's <em>HYDROXIDE</em><em> </em>

Explanation:

You do not call it as hydroxide <em>ion</em><em> </em>because ion always have + or -

I hope this helps

HAVE A GOOD DAY!

5 0
3 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.

4 0
3 years ago
10 points! Please help if you know the answer I need to get 100% on this test :)
miskamm [114]

Answer:

Metal has an high capacity, which allows it to heat up faster and transfer the heat to the contents of the pot or pan.

Explanation:

Because metal pots are made from a narrow range of metals because pots and pans need to conduct heat well.

7 0
3 years ago
Bob measured out 1.60 grams of sodium. He calculates that 1.60 g of
saul85 [17]

Answer:

84.8%

Explanation:

Step 1: Given data

Bob measured out 1.60 g of Na. He forms NaCl according to the following equation.

Na + 1/2 Cl₂ ⇒ NaCl

According to this equation, he calculates that 1.60 g of sodium should produce 4.07 g of NaCl, which is the theoretical yield. However, he carries out the experiment and only makes 3.45 g of NaCl, which is the real yield.

Step 2: Calculate the percent yield.

We will use the following expression.

%yield = real yield / theoretical yield × 100%

%yield = 3.45 g / 4.07 g × 100% = 84.8%

6 0
3 years ago
Which of the following is not present in skeletal structures?
cupoosta [38]

Answer:

cartilage or soft tissue? you didn't give options :/

Explanation:

6 0
3 years ago
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