What is the average atomic mass of element X: X- 10 98%
X - 11 1.5%
X - 12 0.5%
The answers to pick from are 10.025 amu or 11 amu or 10,565 amu or 12.05 amu.

The average atomic mass of element X is 10.025 amu

The average atomic mass of element X = atomic mass of 10 isotope × relative abundance of 10 isotope + atomic mass of 11 isotope × relative abundance of 11 isotope + atomic mass of 12 isotope × relative abundance of 12 isotope

= 10 × 98% + 11 × 1.5 % + 12 × 0.5 %

= 10 × 0.98 + 11 × 0.015 + 12 × 0.005

= 9.8 + 0.165 + 0.06

= 10.025 amu

So, the average atomic mass of element X is 10.025 amu

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the equation that correctly represent the reaction for formation of ammonia is

n2+ 3h2 → 2nh3 (answer d)

1 mole of nitrogen gas (n2) react with 3 moles of hydrogen gas (h2) to form 2 moles of ammonia ( nh3). this is in a process known as haber process were iron is used as a catalyst and reaction take place that a higher temperature and pressure. the process is exothermic hence energy is released.

d: the voltage of the secondary coil is less than that of the primary coil.

im not suree sorry if wrong