Answer:
41. False
42. True
43. False
44. False
45. True
46 - 48. Unsure (I don't take Biology, sorry.)
Explanation:
41.
FeS and HCl are the reactants of the chemical equation. Hence, false.
42.
It is common knowledge that HCl and H₂SO₄ are acids. Hence, true.
43.
Vinegar contains acetic acid CH₃COOH, which isn't a base. Hence, false.
44.
Fluorescence is actually the emittance of light by <em>any substance</em> due to radiation. Hence, false.
45.
Yes, the image produced by a plane mirror is laterally inverted. Hence, true.
Answer:
2.4 g
Explanation:
Step 1: Given data
- Initial pressure (P₁): 755 torr
- Final pressure (P₂): 1.87 atm
Step 2: Convert "P₁" to atm
We will use the conversion factor 1 atm = 760 torr.
755 torr × 1 atm/760 torr = 0.993 atm
Step 3: Convert "T" to K
We will use the following expression.
K = °C + 273.15
K = 25°C + 273.15 = 298 K
Step 4: Calculate the initial number of moles of He
We will use the ideal gas equation.
P₁ × V = n₁ × R × T
n₁ = P₁ × V/R × T
n₁ = 0.993 atm × 16.8 L/(0.0821 atm.L/mol.K) × 298 K
n₁ = 0.682 mol
Step 5: Calculate the final number of moles of He
We will use the ideal gas equation.
P₂ × V = n₂ × R × T
n₂ = P₂ × V/R × T
n₂ = 1.87 atm × 16.8 L/(0.0821 atm.L/mol.K) × 298 K
n₂ = 1.28 mol
Step 6: Calculate the moles of He added
n = n₂ - n₁
n = 1.28 mol - 0.682 mol
n = 0.60 mol
Step 7: Convert "n" to mass
The molar mass of He is 4.00 g/mol
0.60 mol × 4.00 g/mol = 2.4 g
The chemical property deals with the ability of a substance being able to burn is called combustibility [ option b ] .
<u>More</u><u> to</u><u> know</u><u> </u><u>:</u><u>-</u>
<em>1</em><em>)</em><em> </em><em>Combustion</em><em> </em><em>:</em><em>-</em>
Combustion is a chemical process in which a substance reacts rapidly with oxygen and gives out heat.
The fuel can be any one of the 3 states of matter that is - solid , liquid & gases .
Examples of combustible substances :-
Solid - Coal
Liquid - Petrol , Disel , etc.
Gas - Hydrogen , Oxygen , etc .
A non-sandblasted rock could be rough or smooth depending on how it was formed.
A sandblasted rock should be much smoother, since the sand blasts away any rough edges. It will, however, be slightly smaller due to losing those edges.
It is expressed in inches,feet,and pounds, centimeters,meters and kilograms in the metric system.(I hope this helps)
