Answer:
One: <u>Selenium</u> is Paramagnetic
Explanation:
Those compounds which have unpaired electrons are attracted towards magnet. This property is called as paramagnetism. Lets see why remaining are not paramagnetic.
Electronic configuration of Scandium;
Sc = 21 = 1s², 2s², 2p⁶, 3s², 3p⁶, 4s², 3d¹
Sc³⁺ = 1s², 2s², 2p⁶, 3s², 3p⁶
Hence in Sc³⁺ there is no unpaired electron.
Electronic configuration of Bromine;
Br = 35 = 1s², 2s², 2p⁶, 3s², 3p⁶, 4s², 3d¹⁰, 4p⁵
Br⁻ = 1s², 2s², 2p⁶, 3s², 3p⁶, 4s², 3d¹⁰, 4p⁶
Hence in Br⁻ there is no unpaired electron.
Electronic configuration of Magnesium;
Mg = 12 = 1s², 2s², 2p⁶, 3s²
Mg²⁺ = 1s², 2s², 2p⁶
Hence in Mg²⁺ there is no unpaired electron.
Electronic configuration of selenium;
Se = 34 = 1s², 2s², 2p⁶, 3s², 3p⁶, 4s², 3d¹⁰, 4p⁴
Or,
Se = 34 = 1s², 2s², 2p⁶, 3s², 3p⁶, 4s², 3d¹⁰, 4px², 4py¹, 4pz¹
Hence in Se there are two unpaired electrons hence it is paramagnetic in nature.
Here are the answers in order:
1. During a physical change the substance changes physically.
2. The law of conservation of mass is a law stating the conservation of mass cannot be higher than 46mg or lower than 32mg.
3. A hypothesis is a guess that you make before completing a science experiment, it can be considered a law because it is important to know why you are making the guess.
4. During a chemical change the mass is changing colors. This is a representation of a chemical change.
5. Oil is a non-renewable resource, so it cannot demonstrate the conservation of mass.
6. When the color of the substance has changed or when it explodes.
7. Reactants are the objects that react when in a chemical change.
8. If you follow the rule of not going higher than 46mg and not lower than 32mg then it will automatically follow this law.
Chemical Reactions Part One Video:
1. mass
2. erupt-ant
3. reactant
4. object
5. mixtures
6. molecules
7. color changed
Questions again:
1. A chemical reaction
2. A physical change
3. Because if it is no higher than 46mg and no lower than 32mg then it will follow on it's own.
Answer:
1.03 M
Explanation:
Step 1: Write the balanced equation
NaOH + HCl ⇒ NaCl + H₂O
Step 2: Calculate the reacting moles of HCl
30.0 mL (0.0300 L) of 0.500 M HCl react.
0.0300 L × 0.500 mol/L = 0.0150 mol
Step 3: Calculate the moles of NaOH that react with 0.0150 moles of HCl
The molar ratio of NaOH to HCl is 1:1. The moles of NaOH that react are 1/1 × 0.0150 mol = 0.0150 mol.
Step 4: Calculate the molar concentration of NaOH
0.0150 moles of NaOH are in 14.5 mL (0.0145 L).
M = 0.0150 mol/0.0145 L = 1.03 M
Answer:
Explanation:
The wavelength is the distance between two adjacent wavefronts. ... If the wave crosses to the new medium at an angle (not 90 degrees), the change ... When light enters a more optically dense medium, it is refracted closer to the normal. the same as the critical angle, light will travel along the boundary of the 2 mediums.
