Answer:
40% of the energy release by the peanut is 3500 calories
Explanation:
One calorie is defined as the amount of energy required to increase the temperature of one gram of water for one degree Celsius (or one Kelvin)
Equation for energy gain by water is
Q = mcΔT
where, m is the mass of the object
c is the specific heat capacity
ΔT is the change in temperature
c = 1.0 cal/g?°C.
m = 50 g
ΔT = 50°C - 22°C
= 28°C
Q = (50)× (1)× (28)
= 1400calories
The peanut contain 1400calories of energy .
amount that 40% of energy is released to water ,
so,
Q = 1400 calories / 0.4
= 3500 calories
Therefore, 40% of the energy release by the peanut is 3500 calories
Since a percentage is out of 100, do the % / 100
Divide the percent by 100
Answer:
8.0356 * 10^-5 moles of NaHCO3
Explanation:
Sulphuric acid = H2SO4
Sodium bicarbonate = NaHCO3
The reaction between both compounds is given by;
2NaHCO3(aq) + H2SO4(aq) → Na2SO4(aq) + 2CO2(g) + 2H2O(l)
In the reactin above;
2 mol of NaHCO3 neutralizes 1 mol of H2SO4
At stp, 1 mol occupies 22.4 L;
1 mol = 22.4 L = 22400 mL
x mol = 0.9 mL
x = 0.9 / 22400 = 4.0178 * 10^-5 moles of H2SO4
Since 2 mol = 1 mol from the equation;
x mol = 4.0178 * 10^-5
x mol = 2 * 4.0178 * 10^-5
x = 8.0356 * 10^-5 moles of NaHCO3
X-rays are found in the given region.
Answer: Option B
<u>Explanation:</u>
The wavelengths of different waves are studied carefully, and their range is determined according to the frequency they exhibited. And based upon the studies, the electromagnetic waves are classified into eight different categories such as gamma, X-, UV, visible, near IR, middle IR, far IR, micro and radio waves.
And each category has different wavelengths and the given radiation falls under X-rays. The wavelength range of X-rays varies from 1 nm to 1 pm. Here, “nm” stands for nano meter and “pm” stands for “pico meter”.
Answer: 167 g
Explanation:
1) The depression of the freezing point of a solution is a colligative property ruled by this equation:
ΔTf = i × m × Kf
Where:
ΔTf is the decrease of the freezing point of the solvent due to the presence of the solute.
i is the Van't Hoof factor and is equal to the number of ions per each mole of solute. It is only valid for ionic compounds. Here the solute is not ionice, so you take i = 1
Kf is the molal freezing constant and is different for each solvent. For water it is 1.86 m/°C
2) Calculate the molality (m) of the solution
ΔTf = i × m × Kf ⇒ m = ΔTf / ( i × Kf) = 5.00°C / 1.86°C/m = 2.69 m
3) Calculate the number of moles from the molality definition
m = moles of solute / kg of solvent ⇒ moles of solute = m × kg of solvent
moles of solute = 2.69 m × 1.00 kg = 2.69 moles
4) Convert moles to grams using the molar mass
molar mass of C₂H₆O₂ = 62.07 g/mol
mass in grams = number of moles × molar mass = 2.69 moles × 62.07 g/mol = 166.97 g ≈ 167 g
