Question

when a solid is converted directly to a gas, the change of state is called freezing. boiling. condensation. melting. sublimation. question 8 (5 points) saved which of the following numbers is the smallest? 4.0×10^(-8) 4.0×10^(15) 4.0×10^(-2) 4.0×10^(-12) 4.0×10^(-6) question 9 (5 points) saved how many calories are required to raise the temperature of a 35.0 g sample of iron from 25 °c to 35 °c? iron has a specific heat of 0.108 cal/g °c. 93 cal

Explanation:

Step1: Recall change - of - state definitions

Freezing is liquid to solid, boiling is liquid to gas, condensation is gas to liquid, melting is solid to liquid, and sublimation is solid to gas. So the answer to the first question is sublimation.

Step2: Compare scientific - notation numbers

For numbers in scientific notation \(a\times10^{n}\), when \(a\) is the same (\(a = 4.0\) here), the smaller the exponent \(n\), the smaller the number. Among \(- 8\), \(15\), \(-2\), \(-12\), \(-6\), \(-12\) is the smallest exponent for negative exponents. So the smallest number is \(4.0\times10^{-12}\).

Step3: Use heat - calculation formula

The formula for heat \(Q=mc\Delta T\), where \(m = 35.0\ g\), \(c=0.108\ cal/g^{\circ}C\), and \(\Delta T=T_{2}-T_{1}=35^{\circ}C - 25^{\circ}C = 10^{\circ}C\). Then \(Q=(35.0\ g)\times(0.108\ cal/g^{\circ}C)\times(10^{\circ}C)=37.8\ cal\).

Answer:

Question 7: sublimation
Question 8: \(4.0\times10^{-12}\)
Question 9: \(37.8\ cal\)