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lubasha [3.4K]
2 years ago
11

A sample of substance x that has a mass of 326.0 g releases 4325.8 cal when it freezes at its freezing point. if substance x has

a molar mass of 58.45 g/mol, what is the molar heat of fusion for substance x? use q equals n delta h.. 13.31 cal/mol 74.00 cal/mol 775.6 cal/mol 19054.7 cal/mol
Mathematics
1 answer:
zysi [14]2 years ago
7 0

The molar heat of fusion for substance X , given the data is 775.6 cal/mol

<h3>How to determine the mole of the substance X</h3>
  • Mass = 326 g
  • Molar mass = 58.45 g/mol
  • Mole = ?

Mole = mass / molar mass

Mole = (326 / 58.45) moles

<h3>How to determine the heat of fussion</h3>
  • Mole (n) = (326 / 58.45) moles
  • Heat (Q) = 4325.8 cal
  • Heat of fusion (ΔHf) = ?

Q = n × ΔHf

4325.8 = (326 / 58.45) × ΔHf

4325.8 = (326 × ΔHf ) / 58.45

Cross multiply

326 × ΔHf = 4325.8 × 58.45

Divide both sides by 326

ΔHf = (4325.8 × 58.45) / 326

ΔHf = 775.6 cal/mol

Learn more about heat transfer:

brainly.com/question/6363778

#SPJ1

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Bob bought a broken motor scooter, repaired it, and sold the scooter for $130. That was $50 less than 1.5 times what he paid for
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Answer: $120

Step-by-step explanation:

Assume the original price is x.

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Ten years ago 53% of American families owned stocks or stock funds. Sample data collected by the Investment Company Institute in
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Answer:

a) The null and alternative hypothesis are:

H_0: \pi=0.53\\\\H_a:\pi

b) If 300 families were sampled, for a significance level of 5%, there is enough evidence to support the claim that a smaller proportion of American families own stocks or stock funds this year than 10 years ago (P-value = 0.001).

 

Step-by-step explanation:

The claim that we want to have evidence to support is that a smaller proportion of American families own stocks or stock funds this year than 10 years ago.

The hypothesis for this test should state:

- For the null hypothesis, that the population proportion is not significantly different from 53%.

H_0:\pi=0.53

- For the alternative hypothesis, that the population proportion is significantly less than 53%.

H_a: \pi

If 300 families are sampled, we can perform a hypothesis test for a proportion.

The claim is that a smaller proportion of American families own stocks or stock funds this year than 10 years ago.

Then, the null and alternative hypothesis are:

H_0: \pi=0.53\\\\H_a:\pi

The significance level is 0.05.

The sample has a size n=300.

The sample proportion is p=0.44.

The standard error of the proportion is:

\sigma_p=\sqrt{\dfrac{\pi(1-\pi)}{n}}=\sqrt{\dfrac{0.53*0.47}{300}}\\\\\\ \sigma_p=\sqrt{0.00083}=0.029

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z=\dfrac{p-\pi+0.5/n}{\sigma_p}=\dfrac{0.44-0.53+0.5/300}{0.029}=\dfrac{-0.088}{0.029}=-3.065

This test is a left-tailed test, so the P-value for this test is calculated as:

\text{P-value}=P(z

As the P-value (0.001) is smaller than the significance level (0.05), the effect is  significant.

The null hypothesis is rejected.

There is enough evidence to support the claim that a smaller proportion of American families own stocks or stock funds this year than 10 years ago.

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