a) The least number of decimal points is 0 so you should round the answer to 43.
b) The least number of significant figures is 2 so round to 7.3
c)The least number of decimal places is 1 so round to 225.7
d) The least number of significant figures is 3 so round to 92.0
e) The least number of significant figures is 3 so round to 32.4
f) The least number of decimal places is 0 so round to 104m^3
Basically, for addition and subtraction round to the least number of decimal places found in the factors, and for multiplication and division round to the least number of significant figures found in the factors.
Answer: 1.Stars are born in clouds of gas and dust called nebulas.
2.The gas and dust are pulled together by gravity.
3.Heat and pressure cause nuclear fusion, which signals the birth of a star.
Explanation:
Answer:
Solubility indicates the maximum amount of a substance that can be dissolved in a solvent at a given temperature. Such a solution is called saturated,it is calculated by dividing the mass of the compound by mass of the solvent then multiply by the molar concentration.
molar mass of solvent (Agl)= 107.8682 + 126.90447 = 234.77267g/mol
For 0.038M of Nal
molar mass of Nal compound= 22.99 + 126.90447 = 149.89447g/mol
solubility = [ 149.89447 / 234.77267] * 0.038 = 0.024
For 0.05M of AgNO3
molar mass of AgNO3 compound = 107.8682 + 14.01 + 3(16) = 169.8782g/mol
solubility = [169.8782 / 234.77267] * 0.05 = 0.036
For 0.025M of KI
molar mass of KI compound = 39.0983 + 253.8089 = 292.9072g/mol
solublity = [292.9072 / 234.77267] * 0.025 = 0.031
For 0.0125M of Lil
molar mass of Lil compound = 6.941 + 253.8089 = 260.7499g/mol
solubility = [260.7499 / 234.77267] * 0.0125 = 0.014
Therefore the solution with the highest solubility is 0.05M of AgNO3
<span>When two electrical charges, of
opposite sign and equal magnitude, are separated by a distance, a dipole is
established. The size of a dipole is measured by its dipole moment (</span>μμ). Dipole moment is measured in Debye
units, which is equal to the distance between the charges multiplied by the
charge (1 Debye equals 3.34×10−30Cm3.34×10−30Cm). The dipole moment
of a molecule can be calculated by Equation 1.11.1:
μ = qr
where
<span>
<span>μ⃗ μ→ is the dipole moment vector</span>
<span>qiqi is the magnitude of the ithith charge, and</span>
<span>r⃗ ir→i is the vector representing the position
of ithith charge.</span>
</span>
r = μ/q
<span>r = [0.838D(3.34×10−30 C⋅m/ 1D)]/ (1.6×10−19
C) *0.124
</span>
r = 1.41 x10^-10 m
Answer:
Net ionic equation for the reaction between MgCl₂ and NaOH in water:
.
Net ionic equation for the reaction between MgSO₄ and BaCl₂ in water:
.
Explanation:
Start by finding the chemical equations for each reaction:
MgCl₂ reacts with NaOH to form Mg(OH)₂ and NaCl. This reaction is a double decomposition reaction (a.k.a. double replacement reaction, salt metathesis reaction.) This reaction is feasible because one of the products, Mg(OH)₂, is weakly soluble in water and exists as a solid precipitate.
.
MgSO₄ reacts with BaCl₂ in a double decomposition reaction to produce BaSO₄ and MgCl₂. Similarly, the solid product BaSO₄ makes this reaction is feasible.
.
How to rewrite a chemical equation to produce a net ionic equation?
- Rewrite all reactants and products that ionizes completely in the solution as ions.
- Eliminate ions that exist on both sides of the equation to produce a net ionic equation.
Typical classes of chemicals that ionize completely in water:
- Soluble salts,
- Strong acids, and
- Strong bases.
Keep the formula of salts that are not soluble in water, weak acids, weak bases, and water unchanged.
Take the first reaction as an example, note the coefficients:
- MgCl₂ is a salt and is soluble in water. Each unit of MgCl₂ can be written as
and 
. - NaOH is a strong base. Each unit of NaOH can be written as
and 
. - Mg(OH)₂ is a weak base and should not be written.
- NaCl is a salt and is soluble in water. Each unit of NaCl can be written as and
.
.
Ions on both sides of the equation:
- , and
.
Add the state symbols:
.
For the second reaction:
.
.
.
