The question is incomplete, the complete question is;
Which statement describes a difference between electromagnetic and mechanical waves?
A. Mechanical waves cannot be longitudinal, but electromagnetic waves can.
B. Electromagnetic waves cannot move particles, but mechanical waves can.
C. Electromagnetic waves do not require a medium, but mechanical waves do.
D. Mechanical waves do not transfer energy, but electromagnetic waves do.
Answer:
Electromagnetic waves do not require a medium, but mechanical waves do.
Explanation:
A wave is defined as a disturbance along a medium which transfers energy. Waves may be classified as mechanical waves or electromagnetic waves based on their medium of propagation.
A mechanical wave requires a material medium for propagation. An example of a mechanical wave is sound waves. Sound waves are propagated in air.
Electromagnetic waves do not require a material medium for propagation. They can travel through space. An example of electromagnetic waves is light waves.
Answer:
29% is the final concentration
Explanation:
To solve this question we must find the volume of ethanol added and the volume of the whole solution. The concentration will be:
Volume ethanol / Total volume * 100
<em>Volume ethanol:</em>
10mL * 70% = 7mL ethanol
+
20mL * 80% = 16mL ethanol
= 23mL ethanol
<em>Total volume:</em>
10mL + 20mL + 50mL = 80mL
<em>Concentration:</em>
23mL / 80mL * 100
= 29% is the final concentration
Answer:
163.940671 grams
Explanation:
You can view more details on each measurement unit: molecular weight of Na3PO4 or grams This compound is also known as Trisodium Phosphate. The SI base unit for amount of substance is the mole. 1 mole is equal to 1 moles Na3PO4, or 163.940671 grams.
Answer:
0.48g
Explanation:
Given parameters:
Mass of zinc = 15g
Unknown:
Mass of hydrogen gas = ?
Solution:
To solve this problem, we need to state the balanced reaction expression first;
Zn + 2HCl → ZnCl₂ + H₂
Find the number of moles of Zn;
Number of moles = 
= 
= 0.24mol
From the balanced reaction expression;
1 mole of Zn will produce 1 mole of H₂
0.24mole of Zn will produce 0.24mole of hydrogen gas
Mass of hydrogen gas = number of moles x molar mass
= 0.24 x (2 x 1)
= 0.48g
