On temperature 25°C (298,15K) and pressure of 1 atm each gas has same amount of substance:
n(gas) = p·V ÷ R·T = 1 atm · 20L ÷ <span>0,082 L</span>·<span>atm/K</span>·<span>mol </span>· 298,15 K
n(gas) = 0,82 mol.
1) m(He) = 0,82 mol · 4 g/mol = 3,28 g.
d(He) = 10 g + 3,28 g ÷ 20 L = 0,664 g/L.
2) m(Ne) = 0,82 mol · 20,17 g/mol = 16,53 g.
d(Ne) = 26,53 g ÷ 20 L = 1,27 g/L.
3) m(CO) = 0,82 mol ·28 g/mol = 22,96 g.
d(CO) = 32,96 g ÷ 20L = 1,648 g/L.
4) m(NO) = 0,82 mol ·30 g/mol = 24,6 g.
d(NO) = 34,6 g ÷ 20 L = 1,73 g/L.
Answer:
The mass is recorded as 32.075 g
Explanation:
"The first digit of uncertainty is taken as the last significant digit", this is the rule for significant figures in the analysis. The balance measures the mass up to three decimal places, so it makes the most sense to note the whole figure.
Using charles law
v1/t1=v2/t2
v1=49ml
v2=74
t1=7+273=280k
t2=?
49/280=74/t2
0.175=74/t2 cross multiply
0.175t2=74
t2=74/0.175
t2=422k or 149celcius
The temperature reached after four hours of cooling is 140 F (or) 42 C.
Explanation:
A food worker cooled a cup of soup for two hours,
step 1: The temperature reached in <u>two hours</u>= 70 F (or) 21 C
step 2: Then for <u>four hours</u>, <u>it is twice the value</u>
∴ The temperature reached in four hours= 2(70)= 140 F (or) 2(21)= 42 C
Answer:
9.69g
Explanation:
To obtain the desired result, first let us calculate the number of mole of N2 in 7.744L of the gas.
1mole of a gas occupies 22.4L at stp.
Therefore, Xmol of nitrogen gas(N2) will occupy 7.744L i.e
Xmol of N2 = 7.744/22.4 = 0.346 mole
Now let us convert 0.346 mole of N2 to gram in order to obtain the desired result. This is illustrated below:
Molar Mass of N2 = 2x14 = 28g/mol
Number of mole N2 = 0.346 mole
Mass of N2 =?
Mass = number of mole x molar Mass
Mass of N2 = 0.346 x 28
Mass of N2 = 9.69g
Therefore, 7.744L of N2 contains 9.69g of N2
