The initial mass of sodium hydroxide is 3.3 g (answer C)
<u><em>calculation</em></u>
Step 1 : find the moles of iron (ii) hydroxide ( Fe(OH)₂
moles = mass÷ molar mass
from periodic table the molar mass of Fe(OH)₂ = 56 + [16 +1]2 = 90 g/mol
moles is therefore = 3.70 g÷ 90 g/mol = 0.041 moles
Step 2: use the mole ratio to calculate the moles of sodium hydroxide (NaOH)
from given equation NaOH : Fe(OH)₂ is 2 :1
therefore the moles of NaOH = 0.041 x 2 = 0.082 moles
Step 3: find mass of NaOH
mass = moles x molar mass
from the periodic table the molar mass of NaOH = 23 +16 +1 = 40 g/mol
mass = 0.082 moles x 40 g/mol = 3.3 g ( answer C)
Explanation:
First, we will calculate fuel consumption is as follows.
= 4526 g/s
Now, we will calculate the power as follows.
Power = Fuel consumption rate × -enthalpy of combustion
= 
= 
kW
Thus, we can conclude that maximum power (in units of kilowatts) that can be produced by this spacecraft is kW.
Answer: Volume of gas in the stomach, V = 0.0318L or 31.8mL
Explanation:
The number of moles of oxygen will remain constant even though the liquid oxygen will undergo a change of state to gaseous inside the person's stomach due to an increase in temperature.
<em>Number of moles of oxygen gas = mass/molar mass</em>
molar mass of oxygen gas = 32 g/mol
mass of oxygen gas = density * volume
mass of oxygen gas = 1.149 g/ml * 0.035 ml
mass of oxygen gas = 0.040215 g
Number of moles of oxygen gas = 0.0402 g/(32 g/mol)
Number of moles of oxygen gas = 0.00125 moles
<em>Using the ideal gas equation, PV=nRT</em>
where P = 1.0 atm, V = ?, n = 0.00125 moles, R = 0.082 L*atm/K*mol, T = (37 + 273)K = 310 K
<em>V = nRT/P</em>
V = (0.00125moles) * (0.082 L*atm/K*mol) * (310 K) / 1 atm
V = 0.0318L or 31.8mL
A study assessing the effect of anxiety (low vs. high) and stress (low vs. moderate vs. high) on test.
Everyone experiences anxiety occasionally, but persistent anxiety can reduce your quality of life. Though likely best known for altering behavior, worry can have negative effects on our physical health. Anxiety speeds up our heartbeat and breathing, concentrating blood flow to the parts of our brains that need it. You are getting ready for a challenging situation by having this extremely bodily reaction. Test performance may be impacted by anxiety. According to studies, pupils with low levels of test anxiety perform better on multiple-choice question (MCQ) exams than pupils with high levels of anxiety. Studies have indicated that female students have greater levels of test anxiety than male students.
Learn more about anxiety here:
brainly.com/question/4913240
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The correct answer is:
A positively charged nucleus is surrounded by one or more negatively charged electrons
The explanation:
when:
proton is a positively charged elementary particle that is a fundamental constituent of all atomic nuclei.
neutron is a subatomic particle found in the nucleus of every atom except that of simple hydrogen. The particle derives its name from the fact that it has no electrical charge
electron is a negatively charged subatomic particle. It can be either free (not attached to any atom), or bound to the nucleus of an atom .
so, , there are positively charged protons and zero-charged neutrons in the nucleus of an atom. Therefore, the nucleus is positively charged, Surrounding the nucleus, the electrons have negative charge.
Thus, the correct answer is (3): A positively charged nucleus is surrounded by one or more negatively charged electrons is correct.
