Answer: oxygen, hydrogen, sodium, chlorine, lead, iron. Examples of compounds include water ( or hydrogen oxide ) H2O; and Sodium Chloride, NaCl.
Explanation: plz mark brainest
I believe the correct answer from the choices listed above is the third option. The ion would be Al+3. It is obvious because among the options, this is the only substance that has a charge. <span>An </span>ion<span> is an atom or a molecule in which the total number of electrons is not equal to the total number of protons, giving the atom or molecule a net positive or negative electrical charge. </span>
Answer:
45 °C.
Explanation:
From the question given above, the following data were obtained:
Heat (Q) = 1125 J
Mass (M) = 250 g
Final temperature (T₂) = 55 °C
Specific heat capacity (C) = 0.45 J/gºC
Initial temperature (T₁) =?
The initial temperature of the iron can be obtained as illustrated below:
Q = MC(T₂ – T₁)
1125 = 250 × 0.45 (55 – T₁)
1125 = 112.5 (55 – T₁)
Divide both side by 112.5
1125/112.5 = 55 – T₁
10 = 55 – T₁
Collect like terms
10 – 55 = –T₁
–45 = –T₁
Multiply through by –1
45 = T₁
T₁ = 45 °C
Therefore, the initial temperature of the iron is 45 °C
If there is a close container with some water, the following procedures take place.
Initially, the system contains only liquid, and air above it. As evaporation starts (the rate of evaporation is constant for the specific temperature of the water), the molecules from the surface of the liquid escape into vapour state, in the confined space above. Therefore, the level of liquid falls.
Then starts the process of condensation. This is the conversion of vapour into liquid. Initially, escaped molecules (from liquid state) move randomly in all directions and collide with one another. As more and more molecules enter the confined space, some slow-moving molecules are pushed back. They collide with the surface of the liquid to reconvert into liquid.
In the initial stages, the rate of evaporation (constant) is more than the rate of condensation because only small number of molecules are present in the gaseous state. The rate of condensation thereafter gradually increases as the number of molecules in the gaseous phase increases. Finally, a stage is reached when the rate of the two opposing processes is the same.
The state where the rate of evaporation becomes equal to the rate of condensation is called a state of dynamic equilibrium. In such a state, although the amount of liquid level in the container does not change, evaporation has not stopped and the system is not at rest. In fact, the number of molecules, which escape from the liquid to the gaseous phase (due to evaporation), becomes equal to the number of vapour molecules that return to the liquid
Precise is the close proximity of repeated measurements. In order to be precise, you need two or more measurements.
Accurate is the close proximity to the real (or expected) measurement.
<u>For Example: </u>
You are at the grocery store buying watermelons. The sign says that the watermelons all weigh 2 lbs. You weigh 3 of them on the scale next to the watermelon display. Their weights are 1.77, 1.80, and 1.82.
→ The <u>scale is precise</u> because it weighs all 3 of them at nearly the same value.
→ The <u>scale is not accurate </u> because their weights are not close to the expected value of 2.0
You take one of the watermelons to the cashier. The scale at the checkout counter weighs it as 1.99. The scale at the checkout counter is accurate. You cannot determine the precision of the scale at the checkout counter because you have no other values to compare it to.
Answer: Precise CANNOT be determined by one measurement.
Accurate CAN be determined by one measurement.
