Answer:
the ratio of the universe's helium to hydrogen by mass is 2:5 approximately.
Explanation:
To solve this question, we assign arbitrary values to these elements in tandem to the data given in the question.
nH, Number of Hydrogen atoms = X = 100
nHe, Number of Helium atoms = 0.1X = Y = 10
From the data given, by mass:
if the mass of Hydrogen atom = 1g = 100g
therefore, the mass of a Helium atom = 4g (1*4) = 40g
Mass ratio of Helium to Hydrogen = 40:100 = 4:10 = 2:5 approximately
Answer:
Heating a certain substance causes molecules to speed up and spread slightly further apart, having a larger volume that results in a decrease in the density. Cooling a substance causes molecules to slow down and get closer together, occupying a smaller volume that results in the increase in density.
Explanation:
A heterogenous mixture is one which does not have uniform properties throughout. This is likely to happen in a mixture of sand and water because sand does not dissolve in matter and will settle down.
C - Move into the cell, and the cell will shrivel.
Answer:
La réponse ce trouve en bas
Explanation:
13 a) Oui, ce possible parce la solubilité du sel dans l'eau a 60° est majeur que 50g du sel en 150 ml d'eau (333.3 g/L). Dans la graphique la solubilité est de 370 g/L.
b) Jusqu'au 30°C, (30°, 360g(L), ce trouvent ces points dans la ligne rouge.
