Answer: b. Fiona is correct because the diagram shows two individual simple machines.
Explanation:
A mechanical device using which we can change the direction or magnitude of force applied is known as simple machine.
For example, in the given diagram there are two individual simple machines.
The machine helps in changing the direction or magnitude of force applied by the man. As a result, it becomes easy for him to carry different things easily from one place to another.
Thus, we can conclude that the statement Fiona is correct because the diagram shows two individual simple machines, is correct.
A positive reaction for Molisch's test is given by almost all carbohydrates (exceptions include tetroses & trioses). It can be noted that even some glycoproteins and nucleic acids give positive results for this test (since they tend to undergo hydrolysis when exposed to strong mineral acids and form monosaccharides).
Answer: 25 g
Explanation: Given:
Original amount (N₀) = 100 g
Number of half-lives (n) = 11460/5730 = 2
Amount remaining (N) = ?
N = 1/2ⁿ × N₀
N = 1/2^2 × 100
N = 0.25 × 100
N = 25 g
Answer: 7.8125 g
Explanation: Given:
Original amount (N₀) = 500 g
Number of half-lives (n) = 9612/1602 = 6
Amount remaining (N) = ?
N = 1/2ⁿ × N₀
N = 1/2^6 × 500
N = 0.015625 × 500
N = 7.8125 g
Answer: B. carbon tetrachloride, CCI4
Explanation: The other options are incorrect. Let's write the correct formulas:
A. Diarsenic pentoxide - As2O5
C. Sodium dichromate - Na2Cr2O7
D. magnesium phosphide - Mg3P2
Explanation: Acids and bases can be classified in terms of hydrogen ions or hydroxide ions, or in terms of electron pairs. (look at the picture)
Let us note that from the pH scale, a pH of;
0 - 6.9 is acidic
7 is neutral
8 - 14 is basic
a. [H+] = 6.0 x 10-10M
pH= 9.22 is basic
b. [OH-] = 30 × 10-2M
pH = 13.5 is basic
C. IH+1 = 20× 10-7M
pH = 0.56 is acidic
d. [OH-] = 1.0 x 10-7M
pH = 7 is neutral
Answer: 306 L
Explanation: Using the ideal gas law,
PV = nRT
where R = 0.08206 L•atm/(mol•°K), solving for n gives
n = PV/(RT)
n = (845 mmHg) (270 L) / ((0.08206 L•atm/(mol•°K)) (24 °C))
Convert the given temperature to °K and the given pressure to atm:
24 °C = (273.15 + 24) °K ≈ 297.2 °K
(845 mmHg) × (1/760 atm/mmHg) ≈ 1.11 atm
Then the balloon contains
n = (1.11 atm) (270 L) / ((0.08206 L•atm/(mol•°K)) (297.2 °K))
n ≈ 12.3 mol
of He.
Solve the same equation for V :
V = nRT/P
Convert the target temperature to °K:
-50 °C = (273.15 - 50) °K = 223.15 °K
Then the volume under the new set of conditions is
V = (12.3 mol) (0.08206 L•atm/(mol•°K)) (223.15 °K) / (0.735 atm)
V ≈ 306 L
Answer: -166.67 degrees Celsius.
Explanation: The equation of state of an ideal gas, also called the Mendeleev-Clapeyron equation, has the form: PV = nRT, where P is the density of the gas, V is the volume of the gas, n is the molar mass of the gas, T is the temperature of the gas, R is the universal gas constant = 8.314 J/(mol*K)
The gas temperature at a pressure of P = 978 mm. mercury column, molar mass n = 3.7 mol, and volume V = 25.12 liters is -166.67 degrees Celsius.
Answer: B. 7.2 x 10(23rd power)
Explanation:
Avogadro's number is defined as the number of particles found in an amount of substance per mole. It is the factor that relates the moles of a substance to the mass of that substance. We will use Avogadro's number to calculate the number of moles of water. as follows:
Avogadro's number = 1 mol = 6.022 x 10^23 particles.
we will use the conversion factor to calculate the number of moles of water:
1.20 = N x (1mol/6.022x10^23 particles)
N = 1.20/(1mol/6.022x10^23 particles)
N = 7.2 x 10(23rd power)
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