What is the mass in grams of 0.40 moles of sodium borohydride

The mass in grams of 0.40 moles of sodium borohydride is; 15.124g

The chemical formula of sodium borohydride is; NaBH4.

The molar mass of sodium borohydride, NaBH4 is;

From Mass = no. of moles × molar mass.

The mass of 0.40 moles of sodium borohydride is therefore;

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The mass of 0.40 moles NaBH4 is 15.14 grams

Explanation:

Step 1: Data given

sodium borohydride = NaBH4

Number of moles sodium borohydride = 0.40 moles

Atomic mass of Na = 22.99 g/mol

Atomic mass of B = 10.81 g/mol

Atomic mass of H = 1.01 g/mol

Step 2: Calculate the molar mass of NaBH4

Molar mass = 22.99 g/mol + 10.81 g/mol + 4*1.01 g/mol

Molar mass NaBH4 = 37.84 g/mol

Step 3: Calculate mass of NaBH4

Mass NaBH4 = moles NaBH4 * molar mass NaBH4

Mass NaBH4 = 0.40 moles NaBH4 * 37.84 g/mol

Mass NaBH4 = 15.136 grams  ≈ 15.14 grams of NaBH4

The mass of 0.40 moles NaBH4 is 15.14 grams

the dissociation of nickel hydroxide is follows:

the concentration of hydroxide ion is

the equilibrium constant value of nickel hydroxide is = 6.1 * 10^-^1^6 and thus equilibrium equation can be written as:

thus, concentration of ni is 0.23 * 10^-^4 mol /l

the correct answer would be b) volume versus temperature, because they are also directly proportional.