Gasses is the one because gas and gasses
volume of Ni = 25 nL = 25 x 10⁻⁹ L
mol Ni = 25 x 10⁻⁹ L x 1.25 mol/L = 3.125 x 10⁻⁸
mass = mol x Ar Ni
mass = 3.125 x 10⁻⁸ x 59 g/mol
mass = 1.84 x 10⁻⁶ g = 1.84 μg
Answer : Right
Explanation : The direction of reaction tends to proceed on right side under standard conditions; If the change in standard free energy ΔG for a particular reaction is negative. Also if the elements in their most stable forms as they exist under standard conditions. Then ΔG determines the direction and extent of chemical change. But under standard conditions the direction of the reaction will be to right.
<u>Answer:</u> The mass of solid NaOH required is 80 g
<u>Explanation:</u>
Equivalent weight is calculated by dividing the molecular weight by n factor. The equation used is:

where,
n = acidity for bases = 1 (For NaOH)
Molar mass of NaOH = 40 g/mol
Putting values in above equation, we get:

Normality is defined as the umber of gram equivalents dissolved per liter of the solution.
Mathematically,

Or,
......(1)
We are given:
Given mass of NaOH = ?
Equivalent mass of NaOH = 40 g/eq
Volume of solution = 400 mL
Normality of solution = 5 eq/L
Putting values in equation 1, we get:

Hence, the mass of solid NaOH required is 80 g
the value represented by 4.5x10-6 g is 0.0000045 g it is a representation in standard notation
To express enormous figures which are in standard notation like 1,300,000 or exceedingly minuscule quantities like 0.0000000000045, scientists use scientific notation. Scientific notation, also referred to as exponential form, is one of the earliest mathematical techniques. It is well regarded by practitioners. People use scientific notation to handle situations where numbers are too large or too small to be calculated easily. Scientists, engineers, and mathematicians all use this technique. where as standard notation is way writing numbers in normal decimal form. The scientific method id most convenient denoting numbers as the numbers will be either too big or too small.
To learn more about standard notation:
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