In evaporation due to internal heat, kinetic energy of molecules increases and they come to the top and take out that heat with them when they evaporate thus causes cooling
in boiling as heat is given to the molecules so their kinetic energy increases and they start vibrating with great energy and thus causes heating
Answer:
Volume of the sulfuric acid (25cm³), same mass of each metal (1g)
Explanation:
In an experiment, the CONTROL VARIABLE also known as constant is the variable that is kept unchanged for all groups in an experiment. This is done in order not to influence the outcome of the experiment.
In this case, students are trying to investigate the reactivity of four different metals. They added 1 g of each metal to 25cm³ of sulfuric acid and recorded the temperature change. Based on the explanation of control variable above, the VOLUME OF SULFURIC ACID (25cm³) and the MASS OF EACH METAL (1g) are the CONTROL VARIABLES because they are the same or unchanged in this experiment.
Answer: 120N
Explanation:
Given variables are:
force needed = ?
mass of object = 60 kg
acceleration = 2.0 m/s²
Since the magnitude of force depends on the mass of the object and the acceleration by which it moves.
i.e Force = mass x acceleration
Force = 60 kg x 2.0 m/s²
Force = 120 N
Thus, 120 Newton of force is needed to make 60 kg object accelerate at a rate of 2.0 m/s²
Answer is:<span>the yield is 50%.
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Chemical reaction: C + O₂ → CO₂.
n(C) = 0.3 mol; amount of substance.
n(O₂) = 0.3 mol.
From chemical reaction: n(C) : n(CO₂) = 1 : 1.
n(CO₂) = 0.3 mol.
M(CO₂) = 44 g/mol; molar mass of caron(IV) oxide.
m(CO₂) = n(CO₂) · M(CO₂).
m(CO₂) =0.3 mol · 44 g/mol.
m(CO₂) = 13.2 g; mass of carbon(IV) oxide.
the yield = 6.6 g ÷ 13.2 g · 100%.
the yield = 50%.
Sand is because the other ones are liquid
