Answer:b.CaCl2
Explanation:
A compound is a substance resulting when two or more elements are are chemically bonded together either ionically or covalently in a fixed ratio.
From the given options we can see that the only compound there is CaCl2 which is an ionic compound in the fixed ratio of one calcium ion to two chloride ions.
Other options , Cu,Na and Nd are merely pure substance---Elements
Reaction of sodium with water
Sodium metal reacts rapidly with water to form a colourless solution of sodium hydroxide (NaOH) and hydrogen gas (H2). The resulting solution is basic because of the dissolved hydroxide. The reaction is exothermic. During the reaction, the sodium metal may well become so hot that it catches fire and burns with a characteristic orange colour. The reaction is slower than that of potassium (immediately below sodium in the periodic table), but faster than that of lithium (immediately above sodium in the periodic table).
2Na(s) + 2H2O → 2NaOH(aq) + H2(g)
Hello
The word is "pollution"
Hope this helps and have a great day!
Answer:
The density of copper is 0.5 g/mL
Explanation:
Given data:
Mass of copper = 6 g
Volume of copper = 12 mL
Density of copper = ?
Solution:
Formula:
d = m/v
d = density
m = mass
v = volume
d = 6 g/ 12 mL
d = 0.5 g/mL
Thus, the density of copper is 0.5 g/mL
Mass atomic of Ne=20.18 u
Therefore:
molar mass=20.18 g/1 mol
1 mole=6.022*10²³ particles (atoms or molecules)
Then: 6.022*10²³ atoms are contained in 20.18g
Now, We can solve this problem by the three rule.
6.022*10²³ atoms-------------------20.18 g
x------------------------------------------32 g
x=(6.022*10²³ atoms * 32 g)/20.18 g=9.55*10²³ atoms.
Answer: 9.55*10²³ Ne atoms are contained in 32 g of the element.
