Need help in these 2 questions

1 = 7.5m/s and 2 = 8m/s

Explanation:

For question no. 1

Given

wavelength = 5 m

Frequency = 1.5 Hz

Velocity =?

We have the formula that

Velocity = wavelength * frequency

= 5 * 1.5

= 7.5 m/s

For question no. 2

Frequency = 2 Hz

Wavelength = 4 m

Velocity = ?

We have the formula that

Velocity = wavelength * frequency

= 4* 2

= 8 m/s

Hope it will help :)

1. 7.5m/s

2. 8m/s

Explanation: velocity = Wavelength x Frequency so 5m*1.5Hz=7.5m/s and 2Hz*4m=8m/s

c. heat could easily travel through the molecules in the air and escape/enter the flask. removing the air slows down the heat transfer.  

1. for the first question, we must find the mass of the anhydrous salt, mgso₄. the molar mass for mgso₄·7h₂o is 246.47 g/mol, while that of mgso₄ is 120.37 g/mol.7.834 g mgso₄·7h₂o * 1 mol mgso₄·7h₂o/246.47 g * 1 mol mgso₄/1 mol mgso₄·7h₂o * 20.37 g mgso₄/mol = 0.647 g mgso₄

2. mass of water = mass of sample - mass of anhydrous salemass of water = 7.834 - 0.647 = 7.19 gpercent water in hydrate = 7.19/7.834 * 100 = 91.74%