The dependent variable is plant height.
The <em>dependent variable</em> (plant height) is the <em>property that changes</em> as a result something the scientist does.
The <em>independent variable</em> is the <em>property that the scientist changes</em> systematically (the amount of CO_2) to see its effect.
The <em>number of plants</em> and the <em>types of plants</em> are <em>uncontrolled variables</em>. They may or may not affect the heights of the plants.
Answer:
History of composition
Years Material Weight (grains)
1944–1946 gilding metal (95% copper, 5% zinc) 48 grains
1947–1962 bronze (95% copper, 5% tin and zinc) 48 grains
1962 – September 1982 gilding metal (95% copper, 5% zinc) 48 grains
October 1982 – present copper-plated zinc (97.5% zinc, 2.5% copper) 38.6 grains
Answer:
B
Explanation:
It is important to only test one variable at a time because you need to be able to disprove or prove a problem with just one independent variable. When you have several variables in the experiment, it would be impossible to know which variable honestly caused the end result.
Answer:
81°C.
Explanation:
To solve this problem, we can use the relation:
<em>Q = m.c.ΔT,</em>
where, Q is the amount of heat released from water (Q = - 1200 J).
m is the mass of the water (m = 20.0 g).
c is the specific heat capacity of water (c of water = 4.186 J/g.°C).
ΔT is the difference between the initial and final temperature (ΔT = final T - initial T = final T - 95.0°C).
∵ Q = m.c.ΔT
∴ (- 1200 J) = (20.0 g)(4.186 J/g.°C)(final T - 95.0°C ).
(- 1200 J) = 83.72 final T - 7953.
∴ final T = (- 1200 J + 7953)/83.72 = 80.67°C ≅ 81.0°C.
<em>So, the right choice is: 81°C.</em>
