Ka mālama ʻana i ka ikehu no ka hoʻoili wela - nā pilikia a me nā hoʻonā

1. 1-kg wai ma 100 ^o C i hui pū ʻia me 1-kg wai ma 10 ^o C i loko o kahi ʻōnaehana i hoʻokaʻawale ʻia. ʻO ka wela kikoʻī o ka wai he 4200 J/kg ^o C. E hoʻoholo i ka mahana hope loa o ka hui ʻana!

ʻIke ʻia:

Ka nui o ka wai wela (m1 ₎ = 1 kg

Mahana o ka wai wela (T ₁ ) = 100 ^o C

Ka nuipa o ka wai anuanu (m2 ₎ = 1 kg

Mahana o ka wai anuanu (T ₂ ) = 10 ^o C

Makemake ʻia: ʻO ka mahana hope loa (T)

Lōlā:

Wela i nalowale = Wela i loaʻa (ʻōnaehana kaʻawale)

mc ΔT = mc ΔT​​​

m ΔT = m ΔT

m1 ₍ T1 – _T ) = m2 ₍ T – _T2 )

(1)(100 – T) = (1)(T – 10)

100 – T = T – 10

100 + 10 = T + T

110 = 2T

T = 110 / 2

T = 55

ʻO ka mahana hope loa he 55 ^o C.

ʻAʻole maopopo

2. He poloka kēpau 3 kg ma 80^o i kau ʻia i loko o 10 kg o ka wai. ʻO ka wela kikoʻī o ke kēpau he 1400 J.kg^-1C^-1 a ʻo ka wela kikoʻī o ka wai he 4200 J.kg^-1C^-1ʻO ka mahana hope loa ma ke kaulike wela 20^oC. E hoʻoholo i ka mahana mua o ka wai!

ʻIke ʻia:

Nuipaʻa (m1 ₎ = 3 kg

ʻO ka wela kikoʻī o ke kēpau (c ₁ ) = 1400 J.kg ^-1 C ^-1

ʻO ka mahana o ke kēpau (T ₁ ) = 80 ^o C

Ka nui o ka wai (m2 ₎ = 10 kg

ʻO ka wela kikoʻī o ka wai (c ₂ ) = 4200 J.kg ^-1 C ^-1

ʻO ka mahana o ke kaulike wela (T) = 20 ^o C

Makemake ʻia: ʻO ka mahana mua o ka wai (T ₂ )

Lōlā:

Wela i nalowale = Wela i loaʻa

Q kēpau = Q wai

m ₁ c ₁ ΔT = m ₂ c ₂ ΔT

(3)(1400)(80-20) = (10)(4200)(20-T)

(4200)(60) = (42,000)(20-T)

252,000 = 840,000 – 42,000 T

42,000 T = 840,000 – 252,000

42,000 T = 588,000

T = 588,000 / 42,000

T = 14

ʻO ka mahana mua o ka wai he 14 ^° C.

ʻAʻole maopopo

3. He poloka keleawe ma 100^oC i hoʻokomo ʻia i loko o 128 grams o ka wai ma 30 ^oC. ʻO ka wela kikoʻī o ka wai 1 cal.g^-1oC^-1 a ʻo ka wela kikoʻī o ke keleawe 0.1 cal.g^-1oC^-1. Inā ʻo ka mahana o ke kaulike wela 36 ^oC, e hoʻoholo i ka nui o ke keleawe!

ʻIke ʻia:

ʻO ka mahana o ke keleawe (T ₁ ) = 100 ^o C

ʻO ka wela kikoʻī o ke keleawe (c ₁ ) = 0.1 c al.g ^-1o C ^-1

Ka nui o ka wai (m2 ₎ = 128 grams

Mahana o ka wai (T ₂ ) = 30 ^o C

ʻO ka wela kikoʻī o ka wai (c ₂ ) = 1 c al.g ^-1o C ^-1

ʻO ka mahana o ke kaulike wela (T) = 36 ^o C

Makemake ʻia: Nui o ke keleawe ( _m1 )

Lōlā:

Wela i nalowale = Wela i loaʻa

Q keleawe = Q wai

m ₁ c ₁ ΔT = m ₂ c ₂ ΔT

(m ₁ )(0.1)(100-36) = (128)(1)(36-30)

(m ₁ )(0.1)(64) = (128)(1)(6)

(m ₁ )(6.4) = 768

m ₁ = 768 / 6.4

m1 = ₁₂₀

ʻO ke kaumaha o ke keleawe he 120 grams.

ʻAʻole maopopo

4. He poloka hau M-kg ma 0^oC i hoʻokomo ʻia i loko o 340 grams o ka wai ma 20^oC i loko o kahi pahu wai. Inā ʻo ka wela o ka hoʻoheheʻe ʻana no ka wai = 80 kal g^-1, ʻo ka wela kikoʻī o ka wai 1 kal g^{-1 o}C^-1. Hoʻoheheʻe ʻia nā hau a pau a me ka mahana o ke kaulike wela is 5^oC, e hoʻoholo i ka nui o ka hau!

ʻIke ʻia:

Ka nuipa o ka wai (m) = 340 grams

ʻO ka mahana o ka hau (T _hau ) = 0 ^o C

ʻO ka mahana o ka wai (T _wai ) = 20 ^o C

ʻO ka mahana o ke kaulike wela (T) = 5 ^o C

ʻO ka wela o ka fusion no ka wai ( L ) = 80 c al g ^-1

ʻO ka wela kikoʻī o ka wai (c _wai ) = 1 cal g ^{-1 o} C ^-1

Makemake ʻia: Nui o ka hau (M)

Lōlā:

Wela i nalowale = Wela i loaʻa

Wai Q = hau Q

m c ( ΔT) = m _es L _es + m c ( Δ T)

(340)(1)(20-5) = M (80) + M (1)(5-0)

(340)(15) = 80M + 5M

5100 = 85M

M = 5100/85

M = 60 grams

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1. Ke hoʻololi nei i nā unahi mahana
2. Hoʻonui laina
3. Hoʻonui ʻāina
4. Hoʻonui leo
5. wela
6. ʻO ke kūlike mechanical o ka wela
7. Ka wela kikoʻī a me ka mana wela
8. Wela huna, wela o ka hoʻoheheʻe ʻana, wela o ka mahu
9. Ka mālama ʻana i ka ikehu no ka hoʻoili wela