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3 years ago

Examine the following list of questions.

Chemistry

2 answers:

mina [271]3 years ago

4 0

Answer:

because the hundreds of ghosts could kill them.no.no.yes

emmasim [6.3K]3 years ago

3 0

Answer:

1. Because ghosts are terrifying

2. Yes because they get hungry too and they look cute when there chunky

3. depending on the region let's say in the desert a brown mouse will be more likely to survive because it will blend in with the surrounds better then say a white mouse would

4. I mean it says she dose in the nursery rhymes so I would say that she loves them. :)

Explanation:

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SOMEONE PLEASE HELP

Zinaida [17]

Answer:

6. 7870 kg/m³ (3 s.f.)

7. 33.4 g (3 s.f.)

8. 12600 kg/m³ (3 s.f.)

Explanation:

6. The SI unit for density is kg/m³. Thus convert the mass to Kg and volume to m³ first.

1 kg= 1000g

1m³= 1 ×10⁶ cm³

Mass of iron bar

= 64.2g

= 64.2 ÷1000 kg

= 0.0642 kg

Volume of iron bar

= 8.16 cm³

= 8.16 ÷ 10⁶

$= 8.16 \times 10^{ - 6} \: kg$

$\boxed{density = \frac{mass}{volume} }$

Density of iron bar

$= \frac{0.0642}{8.16 \times 10^{ - 6} }$

= 7870 kg/m³ (3 s.f.)

$\boxed{mass = density \: \times volume}$

Mass

= 1.16 ×28.8

= 33.408 g

= 33.4 g (3 s.f.)

8. Volume of brick

= 12 cm³

$= 12 \times 10^{ - 6} \: m^{3} \\ = 1.2 \times 10^{ - 5} \: m ^{3}$

Mass of brick

= 151 g

= 151 ÷ 1000 kg

= 0.151 kg

Density of brick

= mass ÷ volume

$= \frac{0.151} {1.25 \times 10^{ - 5} } \\ = 12600 \: kg/ {m}^{3}$

(3 s.f.)

6 0

3 years ago

The motion of atoms and molecules that most affects temperature is

Oliga [24]

A solid to a liquid, the boiling of water, solid the water molecules vibrate condensed but as a liquid they are still isolated in a controlled area and also reflect off one another more, liquid to a gas they do not and move freely until condensation occurs

3 0

4 years ago

When a chemical reaction is run in aqueous solution inside a calorimeter, the temperature change of the water (and Ccal) can be

Yakvenalex [24]

Answer:

The total change in enthalpy for the reaction is - 81533.6 J/mol

Explanation:

Given the data in the question;

Reaction;

HCl + NaOH → NaCl + H₂O

Where initial temperature is 21.2 °C and final temperature is 28.0 °C. Ccal is 1234.28 J

Moles of NaOH = 50.mL × 1.00 M = 50.0 mmol = 0.0500 mol

Moles of HCl = 50.mL × 1.00 M = 50.0 mmol = 0.0500 mol

so, 0.0500 moles of H₂O produced

Volume of solution = 50.mL + 50.mL = 100.0 mL

Mass of solution m = volume × density = 100.0mL × 1.0 g/mL = 100 g

now ,

Heat energy of Solution q= (mass × specific heat capacity × temp Δ) + Cal

we know that; The specific heat of water(H₂O) is 4.18 J/g°C.

so we substitute

q_soln = (100g × 4.18 × ( 28.0 °C - 21.2 °C) ) + 1234.28

q_soln = 2842.4 + 1234.28

q_soln = 4076.68 J

Enthalpy change for the neutralization is ΔH $_{neutralization}$

ΔH $_{neutralization}$ = -q_soln / mole of water produced

so we substitute

ΔH $_{neutralization}$ = -( 4076.68 J ) / 0.0500 mol

ΔH $_{neutralization}$ = - 81533.6 J/mol

Therefore, the total change in enthalpy for the reaction is - 81533.6 J/mol

6 0

3 years ago

What does one mole of oxygen and one mole of carbon dioxide have in common?

arsen [322]

Answer:

Equal number of moles

Explanation:

Thats life

5 0

3 years ago

A gas has a volume of 240 mL and a pressure of 0.99 atm. If the pressure is decreased to 0.951 atm, what is the new volume of th

irakobra [83]

V2 = 250 ml

Explanation:

Given:

P1 = 0.99 atm. V1 = 240 ml

P2 = 0.951 atm. V2 = ?

We can use Boyle's law to solve for V2

P1V1 = P2V2

V2 = (P1/P2)V1

= (0.99 atm/0.951 atm)(240 ml)

= 250. ml

6 0

3 years ago