Answer:
a) 
2 moles of Zinc sulphide in solid form reacts with 3 moles of Oxygen in gaseous form to give 2 moles of Zinc oxide in solid form and 2 moles of sulphur dioxide in gaseous form.
b) 
1 mole of calcium hydride in solid form reacts with 2 moles of liquid water to give 1 mole of calcium hydroxide dissolved in water and 2 moles of hydrogen in gaseous form.
The chemical reactions are written by writing the chemical formula of the reactants on left side of the arrow followed by chemical formula of the products. The number of atoms of each element must be balanced to follow the law of conservation of mass.
The solution to the polynomial expression since the power of the variable is in the second degree is 6.29 × 10² cm
<h3>What is the power of a variable?</h3>
The power of a variable refers to the exponent of the variable and the highest power of a variable is the degree to which the variable is being raised. From the information given, the highest power of the variable is a polynomial.
Given that:

So, since the exponents are in the same power we are going to add them all together multiplied by their exponent.
i.e.


Learn more about the power of a variable here:
brainly.com/question/2495761
<span>I would say D because the Br is bonded to a tertiary carbon (a carbon bonded to three other carbon atoms). This makes the bond more stable compared to if the Br was bonded to a primary or secondary carbon, and so it is unlikely for spontaneous substitution of Br for OH to occur. Hydrolysis occurs through reaction intermediates that make the making and breaking of C-OH and C-Br bonds respectively more favourable.</span>
Answer:
The bottle is labeled pure so it probably is pure.
Explanation:
When an atom or molecule accepts or looses an electron or electrons it gets either negative charge (when electrons gained) or a positive charge (when looses electron). The negative ion is called Anion and positve ion is called the Cation. An Ion can be Atomic or Polyatomic.
Example:
Sodium when looses one electron forms a cation i.e. Na⁺
Chlorine when gains one electron forms an Anion i.e. Cl⁻
Result:
<span>A negative ion (Anion) differ from an uncharged atom of the same element in the number of electrons. An anion contains more electrons than its corresponding Neutral Element.</span>