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3 years ago

10

Use the ruler to determine the length of this object. Record your answer to the nearest tenth. The object is ____ long.

1 answer:

VLD [36.1K]3 years ago

7 0

The object is 2.7 cm long

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The chemical equation of photosynthesis includes 6O2. What does the small number after the O represent?

blondinia [14]

Its the number of Oxygen molecules

3 0

3 years ago

When a variable is determined by a factor outside of the function or model being evaluated, it is said to be A. statistically i

inna [77]

Answer:

The correct answer is B. exogenous

Explanation:

Let us try to describe exogenous and endogenous variables an exogenous variable value is influenced only by factors outside a model or system and is forced onto the model, while a change in an exogenous variable is known as an exogenous change. Also an endogenous variable is one whose value is influenced only by the system or model under study.

4 0

3 years ago

1. An electric power plant uses energy from burning coal to generate steam at 450 °C. The plant is cooled by 20 °C water

kap26 [50]

Answer:

Explanation:

Efficiency of the electric power plant is $e=1-\frac{T_{2}}{T_{1}}$

Here Temperature of hot source $T_{1} = 450^{o}C=450+273=723 K$

and Temperature of sink $T_{1} = 20^{o}C=20+273=293 K$

Hence the efficiency is $e=1-\frac{293}{723}=0.5947=59.47%$

Now another formula for thermal efficiency Is

$e_{therm}=\frac{Q_{1}-Q_{2}}{Q_{1}}=\frac{W}{Q_{1}}$

Here QI is the of heat taken from source 100 MJ ; Q2 of heat transferred to the sink (river) to be found

W is the of work done and W = QI -Q2

Hence From $e_{therm}=\frac{Q_{1}-Q_{2}}{Q_{1}}=\frac{W}{Q_{1}}$

$W=e(Q_{1})=(0.5947)(100)=59.47MJ$

Hence the of heat transferred to the river Is $Q_{2} -W = (100 -59.47=40.53$

6 0

3 years ago

Which statement defines specific heat capacity for given sample?

Aleks04 [339]

Answer:

D. the quantity of heat that is required to raise 1 g of the sample by 1*C (kelvin) at a constant pressure.

6 0

2 years ago

Read 2 more answers

If 5g of H2 are reacted with excess CO, how many grams of CH3OH are produced, based on a yield of 86%?

Cerrena [4.2K]

Answer: 34.4 g

Explanation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$

$\text{Number of moles of hydrogen}=\frac{5g}{2g/mol}=2.5moles$

As $CO$ is in excess, $H_2$ is the limiting reagent and thus it will limit the formation of products.

$CO+2H_2\rightarrow CH_3OH$

According to stoichiometry:

2 moles of hydrogen produce = 1 mole of $CH_3OH$

2.5 moles of hydrogen produce = $\frac{1}{2}\times 2.5=1.25 moles$ of $CH_3OH$

Mass of $CH_3OH=moles\times {\text {Molar mass}}=1.25\times 32=40g$

But as % yield is 86%, mass of $CH_3OH$ produded is $\frac{86}{100}\times 40=34.4g$

Thus 34.4 g of $CH_3OH$ is produced.

6 0

3 years ago