Kinetic energy=Ek
Ek=(1/2)mv²
Ek=480 J
v=8 m/s
mass=?
Ek=(1/2)mv²
480 J=(1/2)m(8 m/s)²
480 J=(32 m²/s²) m
m=(480 J)/(32 m²/s²)=15 kg
answer: the mass of the object is 15 kilograms.
Answer: 1. C. polar covalent: electrons shared between silicon and sulfur but attracted more to the sulfur
2. B) 
3. B) Fluorine
Explanation:
1. A polar covalent bond is defined as the bond which is formed when there is a difference of electronegativities between the atoms.
Electronegativity difference = electronegativity of sulphur- electronegativity of silicon = 2.5 -1.8 = 0.7
Thus as electronegativity difference is less than 1.7 , the cond is polar covalent and as electronegativity of sulphur is more , the electrons will be more towards sulphur.
2. A molecular compound is usually composed of two or more nonmetal elements. Example:
Ionic compound is formed by the transfer of electrons from metals to non metals. Example:
,
and 
3. For formation of a neutral ionic compound, the charges on cation and anion must be balanced. The cation is formed by loss of electrons by metals and anions are formed by gain of electrons by non metals.
Here K is having an oxidation state of +1 and as the compound formed is KZ, the oxidation state of non metallic element Z should be -1. Thus the element Z is flourine which exists as diatomic gas 
The ideal gas law is P1V1/T1 = P2V2/T2. STP means the temperature is 273 K and pressure is 101.3 kPa. According to this formula, the new volume V2=2.15*58*273/(298*101.3) = 1.13 L.
Assuming you are asking for the names of the elements in that formula , the answer is
carbon
hydrogen
chlorine
fluorine
sodium
oxygen
Answer:
The best practices officers should use when securing a crime scene is option D
D. They should secure a larger area than the actual crime scene
Explanation:
Officers should secure the scene by limiting access to the scene and movement within the scene
Three layers of secure perimeter should be used by officers to secure a crime scene, with the smallest inside perimeter being the actual crime scene
Next to the crime scene, is an inner perimeter which is the designated meeting point/command post
The outer perimeter, which is the third outer layer is to keep onlookers, passerby, and nonessential personnel at safety and out of the actual crime scene.