3 years ago

Which of these is an accurate source of evidence for an investigation?

Chemistry

1 answer:

Feliz [49]3 years ago

4 0

Answer:

observations

Explanation:

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A lead–tin alloy of composition 30 wt% Sn–70 wt% Pb is slowly heated from a temperature of 150°C (300°F).(a) At what temperature

Novay_Z [31]

Answer:

a) 231.9 °C

b) 100% Sn

c) 327.5 °C

d) 100% Pb

Explanation:

This is a mixture of two solids with different fusion point:

$Tf_{Pb}=327.5 C$

$Tf_{Sn}=231.9 C$

<u>Given that Sn has a lower fusion temperature it will start to melt first at that temperature. </u>

So the first liquid phase forms at 231.9 °C and because Pb starts melting at a higher temperature, that phase's composition will be 100% Sn.

The mixture will be completely melted when you are a the higher melting temperature of all components (in this case Pb), so it will all in liquid phase at 327.5 °C.

At that temperature all Sn was already in liquid state and, therefore, the last solid's composition will be 100% Pb.

3 0

3 years ago

Agustina was standing on the edge of a cliff of unknown height holding a bowling ball. She wanted to find the height of the clif

nlexa [21]

Answer:

433 m

Explanation:

Since the fall represents motion under gravity, we use the equation

s = ut - 1/2gt² where s = height of cliff or distance bowling ball falls through, u = initial velocity of bowling ball = 0 m/s(since it starts from rest), t = time = 9.4 s and g = acceleration due to gravity = -9.8 m/s².

So, substituting the values of the variables into the equation, we have

s = 0 m/s × 9.4 s - 1/2 × 9.8 m/s² × (9.4 s)²

s = 0 m - 1/2 × -9.8 m/s² × 88.36 s²

s = 1/2(865.928 m)

s = 432.964

s ≅ 433 m

5 0

3 years ago

A reaction where Oxygen is a reactant.

Goryan [66]

Answer:

chemical