Can someone help please?

Chemistry

2 answers:

weeeeeb [17]3 years ago

8 0

Answer: 63.55

Explanation:

The attached chart shows the calculation. The orange line points to the % abundance of Cu-65, which is the difference of 100% less the % Abundance of Cu-65 (since there are only 2 isotopes).

The weighted average contribution of each istope is calculated (blue arrow) and then summed to find the atomic mass of copper.

attashe74 [19]3 years ago

4 0

<h3>Take the weighted average of the individual isotopes.</h3><h3 /><h3>Explanation:</h3><h3>63</h3><h3>C</h3><h3>u</h3><h3> has </h3><h3>69.2</h3><h3>%</h3><h3> abundance.</h3><h3 /><h3>65</h3><h3>C</h3><h3>u</h3><h3> has </h3><h3>30.8</h3><h3>%</h3><h3> abundance.</h3><h3 /><h3>So, the weighted average is </h3><h3>62.93</h3><h3>×</h3><h3>69.2</h3><h3>%</h3><h3> </h3><h3>+</h3><h3> </h3><h3>64.93</h3><h3>×</h3><h3>30.8</h3><h3>%</h3><h3> </h3><h3>=</h3><h3> </h3><h3>63.55</h3><h3> </h3><h3>amu</h3><h3> .</h3><h3 /><h3>If we look at the Periodic Table, copper metal (a mixture of isotopes but </h3><h3>63</h3><h3>C</h3><h3>u</h3><h3> and </h3><h3>65</h3><h3>C</h3><h3>u</h3><h3> predominate) has an approximate atomic mass of </h3><h3>63.55</h3><h3> </h3><h3>g</h3><h3>⋅</h3><h3>m</h3><h3>o</h3><h3>l</h3><h3>−</h3><h3>1</h3><h3> , so we know we are right.</h3>

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Tems11 [23]

Answer:

None of the options are correct.

The correct answer is 1.10g

Explanation:

First, we'll begin by balancing the equation given above. This is illustrated below:

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Next, let us calculate the mass of HCl that reacted and the mass of H2 produced from the balanced equation. This is illustrated below:

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Mass of HCl from the balanced equation = 2 x 36.5 = 73g

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Now we can easily find the mass of H2 produced when 40g of HCl reacted as shown below:

From the balanced equation,

73g of HCl produced 2g of H2.

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From the calculations made above,

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3 years ago

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ehidna [41]

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