Mass of ZnO added=1.765 g
<h3>
Further explanation:</h3>
Given
30gms of 10%ZnO(Zinc oxide)
15% ZnO
Required
mass of ZnO added
Solution
Amount of ZnO in 30 gms of 10% ZnO =3 gms
For 15% ZnO : x= ZnO added
New solution = 30+x = 15%, so the equation :

an electromagnet wave can go through objects
Answer : The correct answer is 74.83 m/s .
The kinetic energy is energy possessed by any mass which is moving or have some speed . It is product of mass and velocity . It is expressed as :

Where KE = kinetic energy in J or
m = mass in Kg v = speed in m/s²
Unit of KE is Joules (J) .
Givne : KE = 2100 J mass = 0.75 kg v = ?
Plugging value in KE formula =>


Dividing both side by 0.375 kg =>



<span>Nitrogen gas is converted to nitrate compounds by nitrogen-fixing bacteria in soil turns nitrogen gas into root nodules. Nitrogen is the most commonly limiting nutrient in plants. Legumes use nitrogen fixing bacteria, specifically symbiotic rhizobia bacteria, within their root nodules to counter the limitation.</span>
B) 40%
The balanced equation indicates that for every 3 moles of H2 used, 2 moles of NH3 will be produced. So the reaction if it had 100% yield would produce (2.00 / 3) * 2 = 1.333333333 moles of NH3. But only 0.54 moles were produced. So the percent yield is 0.54 / 1.3333 = 0.405 = 40.5%. This is a close enough match to option "b" to be considered correct.