Answer:
Solids can hold their shape because their molecules are tightly packed together. ... Atoms and molecules in liquids and gases are bouncing and floating around, free to move where they want. The molecules in a solid are stuck in a specific structure or arrangement of atoms.
<em>Hope it helps...</em>
 
        
             
        
        
        
Answer:
SeF4 is a polar molecule
Explanation:
SeF4 is a polar molecule because a polar molecule is any molecule that have lone pairs of electrons in the central atom or have atoms that are electronegative and the electrons between that are covalently bonded are not evenly distributed.
The electronegative atoms of flourine in SeF4 are not evenly distributed and kind pairs of electrons are on the central atom.
 
        
             
        
        
        
Answer:
λ = 0.0167 m = 16.7 mm
Explanation:
The wavelength of these radio waves can be found out by using the formula for the speed of radio waves:
v = fλ
where,
v = speed of radio waves = speed of light = 3 x 10⁸ m/s
f = frequency of radio waves = 18 GHz = 18 x 10⁹ Hz
λ = Wavelength = ?
Therefore,
3 x 10⁸ m/s = (18 x 10⁹ Hz)λ
λ = (3 x 10⁸ m/s)/(18 x 10⁹ Hz)
<u>λ = 0.0167 m = 16.7 mm</u>
 
        
             
        
        
        
Answer:
Q = 8.8 kJ 
Explanation:
Step 1: Data given
The specific heat of a solution = 4.18 J/g°C
Volume = 296 mL 
Density = 1.03 g/mL
The temperature increases with 6.9 °C
Step 2: Calculate the mass of the solution
mass = density * volume
mass = 1.03 g/mL * 296 mL
mass = 304.88 grams
Step 3: Calculate the heat 
Q = m*c*ΔT
⇒ with Q = the heat in Joules = TO BE DETERMINED
⇒ with m = the mass of the solution = 304.88 grams
⇒ with c = the specific heat of the solution = 4.18 J/g°C
⇒ with ΔT = the change in temperature = 6.9 °C
Q = 304.88 g * 4.18 J/g°c * 6.9 °C
Q = 8793.3 J = 8.8 kJ
Q = 8.8 kJ 
 
        
             
        
        
        
The first molecule is a sensible molecule having complete octet of each atom such as C, H and O whereas the second molecule having hydrogen present between the aldehyde and methyl group and thus showing hydrogen is making bond with aldehyde and methyl as well which is not possible because hydrogen only having one electron in its octet due to which it can only form a single bond by sharing its valence electron.