Answer:
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Explanation:
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Answer:
D =Average atomic mass = 10.801 amu.
5) True
Explanation:
Abundance of B¹⁰= 19.9%
Abundance of B¹¹ = 80.1%
Atomic mass of B¹⁰ = 10 amu
Atomic mass of B¹¹ = 11 amu
Average atomic mass = ?
Solution:
Average atomic mass = (abundance of 1st isotope × its atomic mass) +(abundance of 2nd isotope × its atomic mass) / 100
Average atomic mass = (10×19.9)+(11×80.1) /100
Average atomic mass = 199 + 881.1 / 100
Average atomic mass = 1080.1 / 100
Average atomic mass = 10.801 amu.
2)A chemical reaction is one in which a new elements is created
True
False
Answer:
In chemical reaction new substances are created.
For example:
Photosynthesis:
It is the process in which in the presence of sun light and chlorophyll by using carbon dioxide and water plants produce the oxygen and glucose.
Carbon dioxide + water + energy → glucose + oxygen
water is supplied through the roots, carbon dioxide collected through stomata and sun light is capture by chloroplast.
Chemical equation:
6H₂O + 6CO₂ + energy → C₆H₁₂O₆ + 6O₂
it is known from balanced chemical equation that 6 moles of carbon dioxide react with the six moles of water and created one mole of glucose and six mole of oxygen.
Answer: The amount of carbon-14 left after 10 years is 25 g
Explanation:
Formula used :
where,
a = amount of reactant left after n-half lives = ?
= Initial amount of the reactant = 100 g
n = number of half lives =
Putting values in above equation, we get:
Therefore, the amount of carbon-14 left after 10 years is 25 g
The question in English is "<span>Determine the mass, in kg, of a material that is contained in a volume of 18L. It is known that the material density is 0.9 g/cm 3"
Answer:
</span>
We can use a simple
equation to solve this problem. <span>
d =
m/v</span><span>
<span>Where </span>d <span>is
the density, </span>m <span>is
the mass and </span>v is the volume.
d = </span>0.9<span> g/cm³
m = ?
v = </span>18 L = 18 x 10³ cm³<span>
By applying the equation,
<span> 0.9 g/cm³ = m / </span></span>18 x 10³ cm³<span>
m = 0.9 g/cm³ x </span>18 x 10³ cm³<span>
<span>
</span>m = 16200 g
m = 16.2 kg
Hence, the mass of
18 L of material is 16.2 kg.</span>
