Answer:
28
Explanation:
it states that the atom is neutral, meaning the number of electrons and protons are the same. so if there are 13 electrons, there are 13 protons. And the mass number is neutrons plus protons. So 13+15 is 28
The absorbance reported by the defective instrument was 0.3933.
Absorbance A = - log₁₀ T
Tm = transmittance measured by spectrophotometer
Tm = 0.44
Absorbance reported in this equipment = -log₁₀ (0.44) = 0.35654
True absorbance can be calculated by true transmittance, Tm = T+S(α-T)
S = fraction of stray light = 6%= 6/100 = 0.06
α= 1, ideal case
T = true transmittance of the sample
Tm = T+S(α-T)
now, T= Tm-S/ 1-S = 0.44-0.06/ 1-0.06 = 0.404233
therefore, actual reading measured is A = -log₁₀ T = -log₁₀ (0.404233)
i.e; 0.3933
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Answer:
Enzyme
Explanation:
An enzyme is an organic catalyst that speeds up a reaction but can be recovered unchanged.
Human lactase consists of 4092 amino acid groups and has a molar mass of about 280 000 u, so it has a complex structure.
The noble gas is Xenon and its molar mass is 131 g/mol.
<h3>What is the molar mass of the noble gas?</h3>
The molar mass of the noble gas is determined as follows;
Let molar mass of unknown gas be M, and mass of gas be m
Density of the noble gas, ρ = 5.8 g/dm³
density = m/V
At STP;
- temperature, T = 273.15 K
- pressure, P = 1 atm
- molar gas constant, R = 0.0821 L.atmK⁻¹mol⁻¹
From ideal gas equation:
PV = nRT
where n = m/M
PV = mRT/M
M = mRT/PV
M = 0.0821 * 273.15 * 5.84/1
Molar mass of the noble gas = 131 g/mol
The noble gas is Xenon which has molar mass approximately equal to 131 g/mol.
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