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27 tháng 12 2023

Câu 2.

Nhiệt lượng bếp tỏa ra trong thời gian \(t=3min=180s\) là:

\(Q=UIt=RI^2t=60\cdot2,5^2\cdot180=675000J\)

Câu 3.

\(I_{Đ1}=\dfrac{U_{Đ1}}{R_{Đ1}}=\dfrac{6}{6}=1A\)

\(I_{Đ2}=\dfrac{U_{Đ2}}{R_{Đ2}}=\dfrac{1,5}{8}=\dfrac{3}{16}A\)

\(I_b=I_{Đ1}-I_{Đ2}=1-\dfrac{3}{16}=\dfrac{13}{16}A\)

\(R_b=\dfrac{U_b}{I_b}=\dfrac{1,5}{\dfrac{13}{16}}=\dfrac{24}{13}\Omega\)

31 tháng 12 2024

1 Kai is tired because he stayed up late watching TV

2 Since I have a broken leg, I fell over while I was playing basketball

3 Sehun is going to be late for school as the bus is late

4 Because Lisa was careless, she broke the cup

5 Rose wants to go home since she feels sick

31 tháng 12 2024

6 Jimin is hungry as he hasn't eaten all day

7 Since plastic bags are very hard to dissolve, they will cause pollution

8 People reuse and recycle bottles and cans as they want to reduce garbage

9 The sea is becoming increasingly polluted since people drop garbage into the sea

10 We shouldn't throw trash onto the water as polluted water can directly do harm to people's health and kill fish

17 tháng 4 2022

\(n_{CaCO_3}=\dfrac{6}{100}=0,06mol\)

\(n_{CH_3COOH}=\dfrac{200}{60}=3,33mol\)

\(2CH_3COOH+CaCO_3\rightarrow\left(CH_3COO\right)_2Ca+CO_2+H_2O\)

       3,33        >     0,06                                                          ( mol )

                              0,06            0,06                     0,06             ( mol )

\(V_{CO_2}=0,06.22,4=1,344l\)

\(m_{\left(CH_3COO\right)_2Ca}=0,06.158=9,48g\)

\(m_{ddspứ}=200+6-0,06.12=205,28g\)

\(C\%_{\left(CH_3COO\right)_2Ca}=\dfrac{9,48}{205,28}.100=4,61\%\)

17 tháng 4 2022

\(n_{CaCO_3}=\dfrac{6}{100}=0,06\left(mol\right)\\ n_{CH_3C\text{OO}H}=\dfrac{200}{60}=3,3\left(G\right)\\ pthh:CaCO_3+2CH_3C\text{OO}H\rightarrow Ca\left(CH_3C\text{OO}\right)_2+H_2O+CO_2\) 
LTL : \(\dfrac{0,06}{1}< \dfrac{3,3}{2}\) 
=> CaCO3 hết 
theo pthh : \(n_{CO_2}=n_{CaCO_3}=0,06\left(mol\right)\) 
\(\Rightarrow V_{CO_2}=0,06.22,4=1,344\left(l\right)\) 
\(\Rightarrow C\%=\dfrac{6}{200}.100\%=3\%\dfrac{\dfrac{ }{ }C\dfrac{ }{ }\dfrac{ }{ }\dfrac{ }{ }\dfrac{ }{ }}{ }\%\)

bài 1: 

\(\left\{{}\begin{matrix}x+y=57\\4x-2y=6\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}4x+4y=228\\4x-2y=6\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}6y=234\\x+y=57\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}y=39\\x=18\end{matrix}\right.\)

27 tháng 10 2019

sao có ai 

sai đề à

27 tháng 10 2019

ai=ab đó

12 tháng 11 2021

a: \(\Leftrightarrow\left\{{}\begin{matrix}3x+6y=4\\x+4y=2\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}y=\dfrac{1}{3}\\x=\dfrac{2}{3}\end{matrix}\right.\)