Answer:
1. 3.70 g Na₂CO₃·10H₂O
2. 50.0 mL of the first solution
Explanation:
1. Prepare the solution
(a) Calculate the molar mass of Na₂CO₃·10H₂O

The molar mass of Na₂CO₃·10H₂O is 286.15 g/mol.
(b) Calculate the moles of Na₂CO₃·10H₂O

(c) Calculate the mass of Na₂CO₃·10H₂O

2. Dilute the solution
We can use the dilution formula to calculate the volume needed.
V₁c₁ = V₂c₂
Data:
V₁ = ?; c₁ = 0.0500 mol·L⁻¹
V₂ = 100 mL; c₂ = 0.0250 mol·L⁻¹
Calculation:

Explanation:
<u>The first one is a base</u>
<u>The second one is an acid</u>
A base has a pH above 7
An acid has a pH below 7
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Answer:
atomic mass of X is 48.0 amu
Explanation:
Let y be the atomic mass of X
Molar mass of O_2 is = 2×16 = 32 g / mol
X + O2 -----> XO_2
According to the equation ,
y g of X reacts with 32 g of O_2
24 g of X reacts with Z g of O_2
Z = ( 32×24) / y
But given that 24.0 g of X exactly reacts with 16.0 g of O_2
So Z = 16.0
⇒ (32×24) / y = 16.0
⇒ y = (32×24) / 16
y= 48.0
So atomic mass of X is 48.0 amu
Explanation:
While both developed and developing countries have contributed to global environmental problems, developed countries with 85% percent of the gross world product and 23% of its population account for the largest part of mineral and fossil-fuel consumption, resulting in significant environmental impacts
The correct answer is option B, that is, the pitch changes from low to high.
The Doppler shift or the Doppler Effect refers to the variation in the wavelength or frequency of a wave in association with an observer who is traveling comparative to the source of the wave. A prime illustration of Doppler shift is the modification of the pitch heard when a vehicle sounding a horn comes towards and move away from an observer.
In comparison to the frequency emitted, the obtained frequency is greater at the time of approach, similar at the instant of passing by, and lower at the time of recession.