The percentage by mass of oxygen in the compound
find the total mass=( 1.900+ 0250 +0.850) = 3
the percentage mass mass of oxgyen/total mass x100
that is (0.850/3) x100=28.33%
Answer:
6. 7870 kg/m³ (3 s.f.)
7. 33.4 g (3 s.f.)
8. 12600 kg/m³ (3 s.f.)
Explanation:
6. The SI unit for density is kg/m³. Thus convert the mass to Kg and volume to m³ first.
1 kg= 1000g
1m³= 1 ×10⁶ cm³
Mass of iron bar
= 64.2g
= 64.2 ÷1000 kg
= 0.0642 kg
Volume of iron bar
= 8.16 cm³
= 8.16 ÷ 10⁶
Density of iron bar
= 7870 kg/m³ (3 s.f.)
7.
Mass
= 1.16 ×28.8
= 33.408 g
= 33.4 g (3 s.f.)
8. Volume of brick
= 12 cm³
Mass of brick
= 151 g
= 151 ÷ 1000 kg
= 0.151 kg
Density of brick
= mass ÷ volume
(3 s.f.)
Answer:
Explanation:
As per Boltzman equation, <em>kinetic energy (KE)</em> is in direct relation to the <em>temperature</em>, measured in absolute scale Kelvin.
Then, <em>the temperature at which the molecules of an ideal gas have 3 times the kinetic energy they have at any given temperature will be </em><em>3 times</em><em> such temperature.</em>
So, you must just convert the given temperature, 32°F, to kelvin scale.
You can do that in two stages.
- First, convert 32°F to °C. Since, 32°F is the freezing temperature of water, you may remember that is 0°C. You can also use the conversion formula: T (°C) = [T (°F) - 32] / 1.80
- Second, convert 0°C to kelvin:
T (K) = T(°C) + 273.15 K= 273.15 K
Then, <u>3 times</u> gives you: 3 × 273.15 K = 819.45 K
Since, 32°F has two significant figures, you must report your answer with the same number of significan figures. That is 820 K.
<span>1.86 moles of hydrogen gas.
Since what the HCl is reacting with hasn't been mentioned, I'll assume zine. In that case, the balanced reaction is
Zn + 2HCl ==> ZnCl2 + H2
So for every 2 moles of HCl used, 1 mole of hydrogen gas will be generated. So let's figure out how many moles of HCl we have and then divide by 2.
Molarity is defined as moles/liter. So a 2.75 M HCl solution has 2.75 moles of HCl per liter. So the total number of moles we have is:
2.75 mole/L * 1.35 L = 3.7125 mol
And since we get 1 mole H2 per mole of HCl, we get:
3.7125 mol / 2 = 1.85625 mol
Rounding to 3 significant figures gives us 1.86 moles of hydrogen gas.</span>
Answer:
Fertilizers play an important role in providing crops with the nutrients they need to grow and be harvested for nutritious food. Fertilizers help deliver enough food to feed the world's population. ...
For example, micronutrients such as zinc are important to human nutrition, especially children.
Explanation:
Hope it is helpful.....
