Answer:
13) 3.9
14) 12000
15) 6800
16) 110
17) 0.00049
18) 120
Explanation:
First we will look at the second digit of given values.
we will draw a line after second digit then we will look the digit after line.
It the digit after line which is 3rd digit is 5 or more than 5 then one will be added to the second digit.
It it is less than five then second digit remain same.
After this we will add zeros to the right till decimal point.
13) 3.948
Round to two significant figures = 3.9
14) 11561.06
Round to two significant figures = 12000
15) 6789.2
Round to two significant figures = 6800
16) 112.6
Round to two significant figures = 110
17) 0.00048888
Round to two significant figures = 0.00049
18) 119.999
Round to two significant figures = 120
Answer:
hydrogen, carbon, nitrogen, oxygen, phosphorus, and sulfur
Explanation:
6 elemants,those are the most improtant ones that make up living organisms.
We are going to use Avogadro's constant to calculate how many molecules of
carbons dioxide exist in lungs:
when 1 mole of CO2 has 6.02 x 10^23 molecules, so how many molecules in
CO2 when the number of moles is 5 x 10^-2
number of molecules = moles of CO2 * Avogadro's number
= 5 x 10^-2 * 6.02 x 10^23
= 3 x 10^22 molecules
∴ There are 3 x 10^22 molecules in CO2 exist in lungs
Answer:
450.0 L.
Explanation:
- We can use the general law of ideal gas: <em>PV = nRT.</em>
where, P is the pressure of the gas in atm.
V is the volume of the gas in L.
n is the no. of moles of the gas in mol.
R is the general gas constant,
T is the temperature of the gas in K.
- If n and T are constant, and have different values of P and V:
<em>(P₁V₁) = (P₂V₂).</em>
<em></em>
V₁ = 760.0 L, P₁ = 450.0 mm Hg,
V₂ = ??? L, P₂ = 760.0 mm Hg (standard pressure = 1.0 atm = 760 mm Hg).
∴ V₂ = (P₁V₁)/(P₂) = (760.0 L)(450.0 mm Hg)/(760.0 mm Hg) = 450.0 L.
It is a less reactive metal then sodium and magnesium